|
|
|
|||||||
|
|||||||||
J Biol Chem, Vol. 275, Issue 19, 14501-14508, May 12, 2000
From the We used muscle contraction, which increases fatty
acid oxidation, as a model to determine whether fatty acid transport is acutely regulated by fatty acid translocase (FAT/CD36). Palmitate uptake by giant vesicles, obtained from skeletal muscle, was increased by muscle contraction. Kinetic studies indicated that muscle
contraction increased Vmax, but
Km remained unaltered.
Sulfo-N-succinimidyl oleate, a specific inhibitor of
FAT/CD36, fully blocked the contraction-induced increase in palmitate
uptake. In giant vesicles from contracting muscles, plasma membrane
FAT/CD36 was also increased in parallel with the increase in long chain
fatty acid uptake. Further studies showed that like GLUT-4, FAT/CD36 is
located in both the plasma membrane and intracellularly (endosomally).
With muscle contraction, FAT/CD36 at the surface of the muscle was
increased, while concomitantly, FAT/CD36 in the intracellular pool was
reduced. Similar responses were observed for GLUT-4. We conclude that
fatty acid uptake is subject to short term regulation by muscle
contraction and involves the translocation of FAT/CD36 from
intracellular stores to the sarcolemma, analogous to the regulation of
glucose uptake by GLUT-4.
Long chain fatty acids
(LCFAs)1 are an important
substrate in many tissues for a diversity of cellular processes such as
membrane synthesis, protein modification, regulation of transcription, and intracellular signaling (1-5). In addition, LCFAs represent an
important source of energy for tissues such as skeletal muscle and the
heart (for review, see Refs. 6 and 7).
LCFAs can enter cells via both passive diffusion and a protein-mediated
mechanism (for review, see Ref. 8). In the past few years a number of
putative LCFA transporter proteins have also been identified. Fatty
acid translocase, the rat homolog of human glycoprotein IV or CD36
(FAT/CD36) (9), and fatty acid transport protein (FATP) (5) are
integral membrane proteins, whereas the plasma membrane-bound fatty
acid-binding protein (FABPpm) (10) is a peripheral membrane protein.
Each of these proteins can increase LCFA uptake when expressed in
various cell lines (5, 10, 11). FABPpm and FAT/CD36 are expressed
ubiquitously among many tissues (for review, see Ref. 12), with the
notable exception that FAT/CD36 is not expressed in liver (9).
The physiologic function and regulation of these putative fatty acid
transporters remain largely unknown. A recent study has shown that FATP
mRNA and mitochondrial aspartate aminotransferase mRNA
(identical to FABPpm; see Ref. 10), but not FAT mRNA, increase in
parallel with increases in fatty acid uptake in adipocytes (9-13-fold)
in Zucker rats with genetic obesity (fa/fa) or
non-insulin-dependent diabetes mellitus (ZDF) (13). But no
changes in fatty acid uptake were observed in hepatocytes in these
animals (13). We have shown recently that chronic muscle contraction (7 days) results in the overexpression of FAT/CD36 along with a
concomitant increase in LCFA uptake into giant sarcolemmal vesicles
(14). In addition, in transgenic mice that overexpress FAT/CD36, LCFA
oxidation is increased (15). These studies (13-15) indicate that fatty
acid uptake is a physiologically regulatable process involving
tissue-specific and LCFA transporter-specific responses.
Whether LCFA uptake can also be regulated acutely (i.e.
within minutes) by LCFA transport proteins is not known. However, this
can be examined in skeletal muscle. LCFAs are a key oxidizable substrate for skeletal muscle (see Ref. 7), and because of its mass
(40% of body weight) and highly variable metabolic rate, skeletal
muscle is a principal site for the removal of LCFAs from the
circulation. Moreover, LCFA uptake and metabolism can be increased rapidly in contracting muscle (16, 17). This is unlikely to be caused
by an increased rate of diffusion because the LCFA gradient across the
plasma membrane is very high, even in resting muscles (18). It would
seem therefore that a rapid increase in LCFA uptake may be mediated, in
an unknown manner, by one or more of the LCFA transporters.
It is well known that glucose uptake is increased when GLUT-4 is
translocated to the plasma membrane. Whether a similar mechanism can
promote LCFA uptake is not known. However, it is possible that FAT/CD36
can be translocated because this protein was present in the plasma
membrane as well as in high and low density microsomal fractions in
Ob17PY fibroblasts that overexpressed FAT/CD36 (11). Therefore, we
hypothesized that the rapid, contraction-induced increase in LCFA
uptake by intact muscle (17) may have been mediated by the
translocation of FAT/CD36, analogous to the contraction-stimulated translocation of GLUT-4 to the surface of this tissue (19, 20). Therefore, we have examined the acute (1-30 min) contraction-induced uptake of palmitate by giant sarcolemmal vesicles, a preparation that
divorces LCFA uptake from its metabolism and is suitable for the study
of LCFA transport across the sarcolemma (20, 21). In addition, we have
used a muscle fractionation procedure to detect surface and
intracellular pools of FAT/CD36. These studies have shown, for the
first time, that LCFA uptake in muscle tissue is subject to short term
regulation by muscle contraction and involves the translocation of
FAT/CD36 from intracellular stores to the sarcolemma, analogous to the
regulation of glucose uptake by GLUT-4.
Female Harlan Sprague-Dawley rats were used in all experiments
(200-250 g). Animals were housed in a controlled environment on a 12-h
light/12-h dark cycle and fed Purina rat chow ad libitum. All procedures were approved by the animal care committee at the University of Waterloo. Animals were anesthetized with an
intraperitoneal injection of sodium pentobarbital (6 mg/100 g of body
mass) prior to all experimental procedures.
Design of Palmitate Uptake Studies by Giant Sarcolemmal
Vesicles--
To examine the transport of fatty acids across the
plasma membranes, giant sarcolemmal vesicles were obtained from resting and contracting rat hind limb skeletal muscles. While the animal was
under anesthesia a small incision was made in one hind limb, and
stimulating electrodes were placed on the exposed sciatic nerve. The
contralateral muscles in the same animal served as resting controls in
all experiments. Muscle contraction consisted of stimulating the
sciatic nerve in one hind limb (10-20 V; 100 Hz, 100-ms trains, 20 tetani/min for 30 min (unless otherwise noted). Immediately after the
contraction (unless otherwise noted) the contracting muscles and the
contralateral resting muscles were removed for the preparation of giant
sarcolemmal vesicles (see below).
Several different experiments were performed. In one series of
experiments we examined palmitate uptake into giant sarcolemmal vesicles at selected times during muscle contraction (min 1, 5, and 30)
as well as 20 and 45 min after the muscle contraction had ceased. In
other experiments we examined the effects of different rates of muscle
contraction (0, 20, and 40 tetani/min) on palmitate uptake by giant
sarcolemmal vesicles. We also examined the effects of muscle
contraction (20 tetani/min) on the kinetics of palmitate uptake into
giant sarcolemmal vesicles. Finally, we examined whether the
contraction-induced increases in vesicular palmitate uptake were
altered by sulfo-N-succinimidyl oleate (SSO), a nonpermeable sulfosuccinimidyl derivative of LCFA which binds covalently to FAT/CD36
(11, 23) (purity > 90%, gift from Dr. N. A. Abumrad, SUNY Stony
Brook, Stony Brook, NY).
Giant Sarcolemmal Vesicle Preparation--
Vesicles from resting
and contracting muscles were prepared as we have described recently
(21, 22). Briefly, rat hind limb muscles were cut into thin layers
(~1-3 mm thick) and incubated for 1 h at 34 °C in 140 mM KCl and 10 mM MOPS (pH 7.4), 150 units/ml collagenase, and 0.01 g/ml aprotinin. The muscle was then washed with
KCl/MOPS and 10 mM EDTA, and the supernatant was collected. Percoll (final concentration 16%) and aprotinin were added to the
supernatant. This supernatant was placed at the bottom of a density
gradient consisting of a 3-ml middle layer of 4% Nycodenz (w/v) and a
1-ml KCl/MOPS upper layer. The samples were spun at 60 × g for 45 min at room temperature. After centrifugation the vesicles were harvested from the interface of the two upper solutions. The vesicles were diluted in KCl/MOPS and recentrifuged at 800 × g for 30 min. Vesicles were used immediately for transport
experiments. Vesicles were also prepared and stored at Fatty Acid Transport--
Palmitate uptake was measured by the
addition of unlabeled palmitate (Sigma) and 0.3 µCi of
[3H]palmitate (Amersham Pharmacia Biotech), and 0.06 µCi of [14C]mannitol (Amersham Pharmacia Biotech) in a
0.1% bovine serum albumin KCl/MOPS solution to 40 µl of vesicles
(~80 µg of protein). Mannitol served as an extracellular space
marker. The reaction was carried out at room temperature for 15 s
unless otherwise noted. Palmitate uptake was terminated by the addition
of 1.4 ml of ice-cold KCl/MOPS containing 2.5 mM HgCl and
0.1% bovine serum albumin. The sample was centrifuged quickly at
maximal speed in a microcentrifuge for 1 min. The supernatant was
discarded, and radioactivity was determined in the tip of the tube.
Nonspecific uptake was measured by adding the stop solution to the
membrane before the addition of the isotopes. When we examined the
effects of the FAT/CD36 inhibitor SSO, vesicles were preincubated with optimal quantities of SSO (50 µg; see Ref. 22) for 30 min and low
concentrations of bovine serum albumin (0.05%). Thereafter, vesicles
were washed before palmitate uptake studies were performed.
Skeletal Muscle Fractionation--
To determine the subcellular
location of FAT/CD36 and its redistribution in contracting muscles we
fractionated resting and contracting (30 min) skeletal muscle
homogenates using procedures to separate surface and intracellular
compartments of this tissue (20, 24) as well as modification of a
continuous Percoll gradient procedure used previously (25). Briefly,
control and 30-min contracting hind limb muscles (1.2-1.5 g) were
minced for 5 min in 10 mM NaHCO3 (pH 7.0), 0.25 M sucrose, 5 mM NaN3, and 100 µM phenylmethylsulfonyl fluoride (buffer A). The minced
muscles were homogenized (1 g/15-ml dilution) using a Polytron
(Brinkmann Instruments) at a low setting of 3 for 5 × 1 s.
The resulting homogenate was centrifuged at 1,300 × g
for 10 min. The supernatant was saved, and the low speed pellets were
resuspended in buffer A (2 g/15 ml), homogenized, and centrifuged
again. Both supernatant fractions were pooled. The low-speed pellet was
resuspended in 0.5 M LiBr, 50 mM Tris (pH 8.5),
and 100 µM phenylmethylsulfonyl fluoride (buffer B) at a
ratio of 1 g of tissue/25 ml and stirred for 4 h. The pooled
1,300 × g supernatant fractions were centrifuged at
9,000 × g for 10 min. The 9,000 × g
pellet was saved, and the supernatant was spun at 190,000 × g for 1 h. The 190,000 × g pellet was
resuspended in 800 µl of buffer A by five strokes using a tightly
fitting Potter-Elvehjem glass homogenizer and subjected to a continuous
Percoll gradient as described below. The LiBr-treated membranes were
centrifuged first at 1,200 × g for 5 min and then at
10,000 × g for 30 min. The LiBr-10,000 × g pellet was saved. The supernatant fraction was centrifuged
at 190,000 × g for 1 h. The LiBr-190,000 × g pellet was resuspended in 1.2 ml of buffer A by 40 strokes
using a tightly fitting Potter-Elvehjem glass homogenizer. 500 µl of
both the 190,000 × g pellet and the LiBr-190,000 × g pellet were layered on top of a 7-ml Percoll suspension
(60%) in 120 mM KCl, 25 mM Hepes (pH 7.0), 5 mM NaN3, and 0.5 mM EGTA (initial
density 1.12 g/ml), resting on a cushion of 1 ml of 1.25 M
sucrose. The resulting gradients were centrifuged at 62,000 × g for 1 h. After centrifugation, 0.5-ml fractions were
collected starting from the top of the tubes. All procedures were
performed at 0 °C. The fractions were stored at Western Blotting--
We examined the effects of muscle
contraction and the recovery from muscle contraction on the appearance
of the fatty acid transport protein FAT/CD36 in the plasma membrane of
the giant sarcolemmal vesicles. For these purposes we separated
proteins using SDS-polyacrylamide gel electrophoresis and Western
blotting as we have described recently (21, 22). To detect FAT/CD36 we
used MO-25 produced by one of our laboratories (26). We also used
antibodies to the monocarboxylate transporter protein 1 (MCT1) (a gift
from Dr. A. P. Halestrap, University of Bristol, Bristol, U. K.) (27,
28) and the glucose transporters GLUT-1 and GLUT-4 (East Acres
Biologicals) to ascertain that the modified fractionation procedures
could detect the well known contraction-induced GLUT-4 translocation
and the lack of GLUT-1 translocation, because GLUT-1 is confined to the
surface of the muscle (for review, see Refs. 29 and 30). MCT1 is also
confined to the plasma membrane and is not altered by muscle
contraction.2
Palmitate Uptake by Giant Sarcolemmal Vesicles
Palmitate Uptake during and after Muscle Contraction--
Uptake
of palmitate by giant vesicles prepared from contracting muscles was
increased (Fig. 1A,
p < 0.05). An increase was already apparent by 1 min
(+20%), and after 5 min the transport rate was increased significantly
(+29%) from that observed in control muscles (p < 0.05, Fig. 1A). By the end of the 30-min contraction period
the palmitate uptake had increased even further (+75%)
(p < 0.05). After muscle contraction was terminated
the rate of palmitate uptake was reduced in a
time-dependent manner (Fig. 1A)
(p < 0.05). 50 min after the contraction had ended, palmitate uptake had returned to levels observed at rest
(p > 0.05).
Rate of Muscle Contraction and Palmitate Uptake--
To examine
the relationship between the rate of muscle contraction and vesicular
palmitate uptake, muscles remained at rest, or they were stimulated to
contract at either 20 or 40 tetani/min. The increase in palmitate
uptake increased in direct proportion to the rate of muscle stimulation
(Fig. 1B). At 20 and 40 tetani/min the palmitate uptake
rates were increased 28% (p < 0.05) and +56% (p < 0.05), respectively, compared with the uptake
rates in resting control muscles (Fig. 1B).
Palmitate Kinetics during Muscle Contraction--
To examine the
effects of muscle contraction on the kinetics of palmitate uptake, rat
hind limb muscles remained at rest or were stimulated at 20 tetani/min.
Palmitate uptake (Vmax), by vesicles prepared
from contracting muscles, was increased ~40% (p < 0.05). The Km (~ 15 nM) was not
altered (Fig. 2).
Effects of Transporter Inhibitor on Contraction-induced Palmitate
Uptake
To determine if the contraction-induced increase in palmitate
uptake was protein-mediated we compared palmitate uptake at rest and at
the end of the 30-min contraction, either in the absence or presence of
SSO, which binds covalently (23, 31, 32) and specifically only to
FAT/CD36 (22). For these purposes vesicles were obtained from resting
and contracting muscles. The vesicles from each treatment were then
subdivided into two pools, those that were pretreated with SSO and
those that were not. In the absence of SSO there was a
contraction-induced increase in palmitate uptake (+47%,
p < 0.05) (Fig. 3). In
vesicles from resting muscles, SSO reduced vesicular palmitate uptake
by 30% (p < 0.05) (Fig. 3). In vesicles obtained from
contracting muscles, SSO reduced palmitate uptake by 58%
(p < 0.05). Palmitate uptake rates did not differ
(p > 0.05) in SSO-treated vesicles obtained from
resting and contracting muscles (Fig. 3). Thus, SSO was able to block completely the increase in the contraction-induced vesicular palmitate uptake (Fig. 3).
Acute Regulation of Fatty Acid Uptake Involves the Cellular
Redistribution of Fatty Acid Translocase*
§,¶
,, Department of Kinesiology, University of
Waterloo, Waterloo, Ontario N2L 3G1, Canada, the ¶ Department of
Physiology, Maastricht University, 6200 MD Maastricht, The Netherlands,
and the ** Thrombosis and Vascular Biology Laboratory, Otsuka America
Pharmaceutical, Inc., Rockville, Maryland 20850
ABSTRACT
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
INTRODUCTION
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
MATERIALS AND METHODS
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
80 °C for
protein and marker enzyme analysis.
80 °C and upon
thawing, used for enzyme assays (5'-nucleotidase) and for
SDS-polyacrylamide gel electrophoresis followed by Western blotting.
Prior to electrophoresis, Percoll particles were removed by
alkalinizing aliquots of the fractions to pH 12.0 by the addition of
NaOH, followed by centrifugation in a microcentrifuge for 2 min. The
supernatant was then neutralized to pH 7-8 by the addition of HCl. In
the resulting Percoll-free fraction samples, the protein content was
determined by the BCA method, and 5 µg of each fraction was subjected
to SDS-polyacrylamide gel electrophoresis and Western blotting.
RESULTS
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
View larger version (14K):
[in a new window]
Fig. 1.
Palmitate uptake by giant sarcolemmal
vesicles at selected time points during muscle contraction (panel
A) and at selected rates of muscle contraction (panel
B) (mean ± S.E.). Panel A, muscles
were electrically stimulated via the sciatic nerve to contract for 1, 5, and 30 min. Thereafter, muscles recovered from contraction for 20 and 45 min. The contralateral muscles from the same animal served
noncontracting controls at each time point. Giant sarcolemmal vesicles
were prepared at each time point, and palmitate uptake was determined
as described under "Materials and Methods." Noncontracting muscles
have been grouped at t = 0 (n = 22),
and sample sizes at min 1, 5, 30, 50, and 75 were 5, 4, 19, 6, and 4 ,respectively (p < 0.05, ANOVA). * significantly
different from rest, p < 0.05; ** significantly
different from min 5, p < 0.05; *** significantly
different from min 30, p < 0.05. Panel B,
muscles were electrically stimulated via the sciatic nerve to contract
for 30 min at 20 and 40 tetani/min. The contralateral muscles from the
same animal served as noncontracting controls at each intensity of
stimulation. Giant sarcolemmal vesicles were prepared at the end of
contraction, and palmitate uptake was determined as described under
"Materials and Methods." Noncontracting muscles have been grouped
at t = 0 (n = 33), and sample sizes at
20 and 40 tetani/min were 17 and 16, respectively. * p < 0.05 compared with rest; ** p < 0.05 compared with
rest and to 20 tetani/min.
View larger version (14K):
[in a new window]
Fig. 2.
Palmitate uptake in relation to unbound
palmitate concentrations in resting and contracting muscles (30 min at
20 tetani/min). Muscles were electrically stimulated via the
sciatic nerve to contract for 30 min at 20 tetani/min
(n = 6-7 at each concentration). The contralateral
muscles from the same animal served as noncontracting controls. Giant
sarcolemmal vesicles were prepared at the end of contraction, and
palmitate uptake was determined as described under "Materials and
Methods." The unbound palmitate was determined from the bovine serum
albumin/palmitate molar ratio according to equations of Richieri
et al. (49).
View larger version (31K):
[in a new window]
Fig. 3.
Effects of SSO on contraction-induced
palmitate uptake. Muscles were electrically stimulated via the
sciatic nerve to contract for 30 min at 40 tetani/min. The
contralateral muscles from the same animal served as noncontracting
control muscles. Giant sarcolemmal vesicles were prepared at the end of
contraction. Vesicles from both resting and contracting muscles were
separated into two pools; one was preincubated with SSO, and the other
pool was not (see "Materials and Methods"), after which palmitate
uptake was determined (see "Materials and Methods"). SSO is a
specific inhibitor of FAT/CD36. * p < 0.05 contraction
compared with rest. ** p < 0.05, SSO-treated vesicles
compared with untreated vesicles.
Palmitate Uptake and FAT/CD36 Protein in Giant Sarcolemmal Vesicles
To compare the changes in palmitate palmitate uptake with the
changes in FAT/CD36, each of these parameters was determined in giant
vesicles obtained from muscles at rest, at the end of 30-min
contraction, and after recovery from muscle contraction (Fig.
4). After 30 min of contraction there was
a marked increase in palmitate uptake (+65%, p < 0.05) and in FAT/CD36 (+40%, p < 0.05). At the end of
the recovery period palmitate uptake and FAT/CD36 had both returned to
levels observed in vesicles obtained from resting muscles (Fig. 4,
p > 0.05). During these experiments there were no
changes in the membrane-associated MCT1 (data not shown).
|
Subcellular Distribution of GLUT-1, GLUT-4, Transferrin, and FAT/CD36
Fractions of the muscle samples obtained by continuous Percoll density gradients were characterized immunologically and enzymatically (Table I and Fig. 5). GLUT-1, MCT1, and 5'-nucleotidase were most prominently present in the surface muscle fractions and not detected in the intracellular fractions (Table I). The transferrin receptor has been used as a marker of the light microsomal/endosomal compartment (33, 34). In the present studies, The transferrin receptor was present both in the intracellular fraction and at the surface of the membrane (Table I). GLUT-4 was present in greater quantities in the intracellular fraction than at the surface of the muscle (Fig. 5). As expected, insulin reduced the intracellular GLUT-4 and increased the surface GLUT-4 (Fig. 5). The fractions obtained from resting muscle showed a large pool of FAT/CD36 at the surface of the muscle as well as an intracellular pool of FAT/CD36 (Fig. 5).
|
|
Effects of Muscle Contraction on the Redistribution of FAT/CD36
Our primary aim was to examine the effects of muscle contraction on the subcellular redistribution of FAT/CD36. As a positive control for these studies we also examined the effects of electrically induced muscle contraction on GLUT-1, MCT1, transferrin receptor (Table I), and GLUT-4 (Fig. 5). The GLUT-1, MCT1, and transferrin receptor distributions were not altered by muscle contraction (Table I), whereas GLUT-4 was reduced in the intracellular pool (p < 0.05; Fig. 5) and was increased in muscle surface fractions (p < 0.05; Fig. 5). These results for GLUT-1 and GLUT-4 are consistent with previous reports (20, 29, 30).
With 30 min of electrically induced muscle contraction the
intracellular FAT/CD36 was reduced, and the surface FAT/CD36 was increased (Fig. 5). There was a significant reduction in intracellular FAT/CD36 and an increase in surface FAT/CD36 (p < 0.05; Fig. 5). This paralleled the responses of GLUT-4 (Fig. 5).
| |
DISCUSSION |
|---|
|
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
|
|---|
There are a number of novel observations in the present studies. First, by using a muscle contraction model we have shown, for the first time, that fatty acid uptake can be acutely regulated. Second, FAT/CD36, one of the fatty acid transport proteins, is present both at the plasma membrane and in an intracellular pool in skeletal muscle. Third, with muscle contraction FAT/CD36 is translocated from an intracellular pool to the cell surface. Finally, SSO, which binds covalently to FAT/CD36 (23), inhibited the contraction-induced increase in LCFA uptake. Thus, our studies have shown that the uptake of fatty acids across the plasma membrane is regulated acutely by muscle contraction, involving the translocation of FAT/CD36 from an intracellular pool to the surface of the muscle.
One of the strengths of our work is that we have used the giant sarcolemmal vesicle preparation to examine LCFA transport. It is well known that the determination of protein-mediated uptake of substrates across the plasma membrane requires a system in which transport and metabolism are necessarily divorced. To date, determinations of protein-mediated LCFA uptake in tissues such as adipocytes (13, 35), hepatocytes (36), and cardiac myocytes (13, 37) have always been confounded by the concurrent LCFA metabolism. This has been a severe limitation in these studies because it is not clear whether saturation of LCFA uptake is attributable to protein-mediated events at the plasma membrane or enzymatic steps in LCFA metabolism. The giant sarcolemmal vesicle preparation used in this study avoids entirely the problem of metabolism when determining substrate uptake (38, 39), including the uptake of fatty acids (21, 22). We (21, 22) have demonstrated previously that giant vesicles derived from skeletal muscle and heart are an ideal system for the study of protein-mediated fatty acid uptake. Briefly, we (21, 22) have shown that in these giant vesicles (a) initial rates of LCFA uptake can be determined (uptake is linear up to 25 s)3; (b) the giant vesicles contain, in great excess, cytosolic fatty acid-binding protein, which acts as an intravesicular fatty acid sink; (c) all of the palmitate taken up by the vesicles is fully recovered as palmitate from inside the vesicles; and (d) none of the palmitate taken up is esterified, oxidized, or associated with the plasma membrane. Thus, the giant vesicle preparation used in the present study is a well characterized, appropriate system for examining protein-mediated LCFA uptake across the plasma membrane.
In recent years the identification of a number of LCFA transport proteins has led to studies showing that LCFA transporters or their transcripts may be altered by chronic alterations in metabolism (diabetes (40), obesity (13), fasting (41)) or by chronically increased muscle activity (14, 42). Until the present studies there had been no evidence to indicate that LCFA uptake is regulated acutely by a fatty acid transport protein, although based on work in perfused, contracting muscle it was speculated that this might be the case (43).
We have shown previously that in muscle and heart, vesicular palmitate uptake is protein-mediated because it can be inhibited by trypsin and phloretin. Moreover, oleate competes with palmitate for uptake, whereas neither glucose nor octanoate competes with palmitate uptake (22). There are a number of candidate LCFA transporters (FAT/CD36, FATP1, FABPpm) that are implicated in LCFA uptake in a number of tissues (8, 12). Among these, FAT/CD36 appears to be a key LCFA transport protein in skeletal muscle. When FAT/CD36 was increased in chronically stimulated muscles (24 h/day, 7 days), palmitate uptake by giant sarcolemmal vesicles was increased (14). In transgenic mice that overexpress FAT/CD36, palmitate oxidation is increased, but only when muscles are contracting (15). A null mutation in FAT/CD36 reduced adipocyte LCFA uptake and increased circulating levels of fatty acids (44), indicating that LCFA uptake by peripheral tissues was impaired. Collectively, these studies have begun to show that FAT/CD36 is a key LCFA transport protein in adipocytes and skeletal muscle.
The inhibition of the contraction-induced increase in LCFA transport by SSO provides evidence that the fatty acid transport protein FAT/CD36 promoted the contraction-induced increase in vesicular fatty acid uptake. We have shown previously that SSO, a sulfosuccinimidyl derivative of oleate, inhibits LCFA uptake in muscle and heart, but not in liver, which does not express FAT/CD36 (22). The inhibition of LCFA uptake by SSO varies among tissues (8). Our studies suggest that this is attributable to differences in the surface availability of FAT/CD36. In giant vesicles from the heart, which contain more FAT/CD36 than giant vesicles obtained from skeletal muscles, SSO inhibits LCFA uptake more (70% inhibition) than in skeletal muscle vesicles (50% inhibition) (22). Similarly, in the present studies, SSO reduced vesicular LCFA uptake further in contracting muscles (58% inhibition) than in resting muscles (30% inhibition) because plasma membrane concentrations of FAT/CD36 were increased in contracting muscles. In our studies (22) and others (8) SSO does not fully suppress LCFA uptake, and this implies that other mechanisms such as LCFA diffusion and/or the role of other LCFA transport proteins are also important in taking up LCFAs across the plasma membrane. Nevertheless, the complete inhibition of the contraction-induced uptake of palmitate by SSO in the present studies indicates that the function of this transport protein is associated with a need to increase the uptake of LCFAs when the rate of their oxidation is increased (i.e. during muscle contraction). Support for this is also derived from our studies with transgenic mice that overexpress FAT/CD36. In muscles from these animals, skeletal muscle LCFA oxidation was increased, but only when muscles were contracting, not when muscles remained at rest (15).
Several lines of evidence pointed toward a translocation mechanism for increasing LCFA uptake by FAT/CD36. The kinetic studies demonstrated an increase in Vmax in vesicles derived from stimulated muscles, suggesting that muscle contraction increased the number of transport proteins at the surface of the muscle. This was confirmed because contraction increased the amount of vesicular FAT/CD36. This increase was not attributable to de novo protein synthesis because there was no increase in total FAT/CD36 during the 30-min contraction period (data not shown). Therefore, the increase in vesicular FAT/CD36 was most likely accounted for by a translocation of FAT/CD36 from an intracellular compartment(s) to the surface.
Although the translocation of GLUT-4 is a well recognized mechanism by which glucose flux into the muscle is increased (for review, see Ref. 29), it was not known previously that there was also an intracellular, translocatable FAT/CD36 pool in muscle. Our fractionation studies established that like GLUT-4, FAT/CD36 was present both at the surface of the muscle and in an intracellular pool. Consistent with other studies (29, 30), muscle contraction translocated GLUT-4, but not GLUT-1, to the muscle surface. The important new observation is that muscle contraction also translocated FAT/CD36.
The redistribution of GLUT-4 among subcellular compartments in muscle or fat cells has been taken, for many years, as evidence that this glucose transporter is translocated from intracellular sites to the surface of the tissue, thereby stimulating glucose uptake. A similar interpretation is therefore warranted in the present studies, namely that FAT/CD36 is translocated from an intracellular compartment to the the surface of the muscle, which then facilitates an increase in LCFA uptake. The changes in LCFA uptake and FAT/CD36 in contracting muscle are not simply correlative, but these are causally related. The evidence for this are the studies with SSO. SSO binds covalently to FAT/CD36 (23), and SSO inhibits LCFA transport in tissues that express FAT/CD36 (muscle and heart (22)), but not in tissues in which FAT/CD36 is not expressed (i.e. liver (22)). In the present studies SSO inhibited the contraction-induced palmitate transport. Because of this critical experiment and other studies (22, 23), the parallel changes in vesicular LCFA uptake and FAT/CD36 in the plasma membrane, during and after contraction, can be seen as being related in a causal manner. Presumably, there are also other physiologic stimuli that can also increase LCFA uptake via the translocation of FAT/CD36; these, however, remain to be identified.
The exact mechanism of protein-facilitated LCFA transport is not known. Besides FAT/CD36 there are several additional fatty acid transporter proteins (FABPpm (10) and FATP (5, 45)) that may also be involved in the transport process. A model involving their potential interactions has been presented (46), but experimental evidence is lacking for this model. Recently, we have shown that FATP expression in giant vesicles is correlated inversely with fatty acid uptake, whereas both FAT/CD36 and FABPpm are correlated positively with fatty acid uptake in giant vesicles obtained from heart and red and white muscles (22). We have also observed that FABPpm and FAT/CD36 may interact with each other to facilitate LCFA uptake across the sarcolemma (22). Thus, if FABPpm is present in excess at the plasma membrane, then the translocation of FAT/CD36, and its possible association with FABPpm, may augment the rate of LCFA transfer from FABPpm because of an increased number of FAT/CD36 proteins.
Our findings may also have clinical relevance. In animal models of metabolic diseases (obesity, diabetes) LCFA uptake is increased in adipocytes and cardiac myocytes (13). Although this may be associated with altered expression of LCFA transport proteins, it is also possible that the translocation of FAT/CD36 is altered. It is now well known that insulin resistance is often associated with postreceptor defects in the signaling pathway that stimulates GLUT-4 translocation to the cell's surface (29, 47). Moreover, it will also be important to determine how alterations in glucose and LCFA transport are related because LCFAs can impair insulin action (48).
In summary, we have shown that muscle contraction increases LCFA uptake
into giant sarcolemmal vesicles. Kinetic studies revealed that
contraction increased Vmax but not
Km of palmitate uptake. Inhibition of the
contraction-induced LCFA uptake by SSO, a specific inhibitor of
FAT/CD36, indicated that this transport protein was the key component
in augmenting LCFA uptake. The increase in Vmax
is consistent with the increase in FAT/CD36 in the plasma membrane of
giant sarcolemmal vesicles. Further studies have shown that FAT/CD36 is
redistributed from an intracellular location to the surface of the
muscle, indicating that this protein is being translocated in skeletal
muscle, when the need for LCFA metabolism is increased by muscle
contraction. This is similar to the contraction-induced translocation
of GLUT-4 from an intracellular compartment to the surface of the
muscle. Whether other physiologic stimuli can also translocate FAT/CD36
is not known. Thus, the present studies have identified an entirely new
mechanism regulating fatty uptake by contracting skeletal muscle.
Whether fatty acid transport represents the rate-limiting step in fatty
acid metabolism remains to be determined.
| |
ACKNOWLEDGEMENTS |
|---|
We thank Dr. A. P. Halestrap, University of Bristol, Bristol, U. K., for providing the MCT1 antibody, and Dr. N. A. Abumrad, SUNY, Stony Brook, N. Y., for providing the SSO. We also thank Dr. M. van Genderen, Technical University of Eindhoven, Eindhoven, The Netherlands, for performing the purity check of SSO.
| |
FOOTNOTES |
|---|
* This work was supported by a grant from the Medical Research Council of Canada.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
§ To whom correspondence should be addressed. Tel.: 1-519-888-1211 (ext. 5214); Fax: 1-519-746-6776; E-mail: abonen@healthy.uwaterloo.ca.
Dekker postdoctoral fellow of the Netherlands Heart Foundation.
2 A. Bonen, unpublished data.
3 A. Bonen, J. J. F. P. Luiken, Y. Arumugam, J. F. C. Glatz, and N. N. Tandon, unpublished data.
| |
ABBREVIATIONS |
|---|
The abbreviations used are: LCFA, long chain fatty acids; FAT/CD36, fatty acid translocase, the rat homolog of human glycoprotein IV or CD36; FATP, fatty acid transport protein; FABPpm, plasma membrane-bound fatty acid-binding protein; SSO, sulfo-N-succinimidyl oleate; MOPS, 4-morpholinepropanesulfonic acid; MCT1, monocarboxylate transporter protein 1.
| |
REFERENCES |
|---|
|
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
|
|---|
| 1. |
Amri, E. Z.,
Bonino, F.,
Ailhaud, G.,
Abumrad, N. A.,
and Grimaldi, P. A.
(1995)
J. Biol. Chem.
270,
2367-2371 |
| 2. |
Distel, R. J.,
Robinson, G. S.,
and Spiegelman, B. M.
(1992)
J. Biol. Chem.
267,
5937-5941 |
| 3. | Glatz, J. F., Borchers, T., Spener, F., and van der Vusse, G. (1995) Prostaglandins Leukotrienes Essent. Fatty Acids 52, 121-127[CrossRef][Medline] [Order article via Infotrieve] |
| 4. |
Newsholme, E. A.,
Calder, P.,
and Yaqoob, P.
(1993)
Am. J. Clin. Nutr.
57,
738S-751S |
| 5. | Schaffer, J. E., and Lodish, H. F. (1994) Cell 79, 427-436[CrossRef][Medline] [Order article via Infotrieve] |
| 6. |
van der Vusse, G. J.,
Glatz, J. F. C.,
Stam, H. C. G.,
and Reneman, R. S.
(1992)
Physiol. Rev.
72,
881-940 |
| 7. | van der Vusse, G. J., and Reneman, R. S. (1996) in Handbook of Physiology. Exercise: Regulation and Integration of Multiple Systems (Rowell, L. B. , and Shepherd, J. T., eds) , pp. 952-994, American Physiological Society, Bethesda, MD |
| 8. |
Abumrad, N. A.,
Harmon, C.,
and Ibrahimi, A.
(1998)
J. Lipid Res.
39,
2309-2318 |
| 9. |
Abumrad, N. A.,
El-Maghrabi, M. R.,
Amri, E.-Z.,
Lopez, E.,
and Grimaldi, P.
(1993)
J. Biol. Chem.
268,
17665-17668 |
| 10. |
Isola, L. M.,
Zhou, S. L.,
Kiang, C. L.,
Stump, D. D.,
Bradbury, M. W.,
and Berk, P. D.
(1995)
Proc. Natl. Acad. Sci. U. S. A.
92,
9866-9870 |
| 11. |
Ibrahimi, A.,
Sfeir, Z.,
Magharaine, H.,
Amri, E. Z.,
Grimaldi, P.,
and Abumrad, N. A.
(1996)
Proc. Natl. Acad. Sci. U. S. A.
93,
2646-2651 |
| 12. | Glatz, J. F. C., Van Nieuwenhoven, F. A., Luiken, J. J. F. P., Schaap, F. G., and van der Vusse, G. J. (1997) Prostaglandins Leukotrienes Essent. Fatty Acids 45, 373-378 |
| 13. |
Berk, P. D.,
Zhou, S.-L.,
Kiang, C.-L.,
Stump, D.,
Bradbury, M.,
and Isola, L. M.
(1997)
J. Biol. Chem.
272,
8830-8835 |
| 14. | Bonen, A., Dyck, D. J., Ibrahimi, A., and Abumrad, N. A. (1999) Am. J. Physiol. 276, E642-E649 |
| 15. |
Ibrahimi, A.,
Bonen, A.,
Blinn, W. D.,
Hajri, T.,
Li, X.,
Zhong, K.,
Cameron, R.,
and Abumrad, N. A.
(1999)
J. Biol. Chem.
274,
26761-26766 |
| 16. | Dyck, D. J., and Bonen, A. (1998) Am. J. Physiol. 275, E888-E896 |
| 17. | Gorski, J., and Bonen, A. (1997) Mol. Cell. Biochem. 166, 73-83[CrossRef][Medline] [Order article via Infotrieve] |
| 18. |
van der Vusse, G. J.,
and Roemen, T. H. M.
(1995)
J. Appl. Physiol.
78,
1839-1843 |
| 19. |
Goodyear, L. J.,
Hirshman, M. F.,
and Horton, E. S.
(1991)
Am. J. Physiol.
261,
E795-E799 |
| 20. |
Roy, D.,
Johannsson, E.,
Bonen, A.,
and Marette, A.
(1997)
Am. J. Physiol.
273,
E688-E694 |
| 21. | Bonen, A., Luiken, J. J. F. P., Lui, S., Dyck, D. J., Kiens, B., Kristiansen, S., Turcotte, L., van der Vusse, G. J., and Glatz, J. F. C. (1998) Am. J. Physiol. 275, E471-E478 |
| 22. |
Luiken, J. J. F. P.,
Turcotte, L. P.,
and Bonen, A.
(1999)
J. Lipid Res.
40,
1007-1016 |
| 23. | Harmon, C. M., Luce, P., Beth, A. H., and Abumrad, N. A. (1991) J. Membr. Biol. 121, 261-268[CrossRef][Medline] [Order article via Infotrieve] |
| 24. |
Dombrowski, L.,
Roy, D.,
Marcotte, B.,
and Marette, A.
(1996)
Am. J. Physiol.
270,
E667-E676 |
| 25. | Luiken, J. J. F. P., Aerts, J. M. F. G., and Meijer, A. J. (1996) Eur. J. Biochem. 235, 564-573[Medline] [Order article via Infotrieve] |
| 26. | Matsuno, K., Diaz-Ricard, M., Montgomery, R. R., Aster, T., Jamieson, G. A., and Tandon, N. N. (1996) Br. J. Haematol. 92, 960-967[CrossRef][Medline] [Order article via Infotrieve] |
| 27. |
McCullagh, K. J. A.,
Poole, R. C.,
Halestrap, A. P.,
O'Brien, M.,
and Bonen, A.
(1996)
Am. J. Physiol.
271,
E143-E150 |
| 28. |
McCullagh, K. J. A.,
Poole, R. C.,
Halestrap, A. P.,
Tipton, K. F.,
O'Brien, M.,
and Bonen, A.
(1997)
Am. J. Physiol.
273,
E239-E246 |
| 29. | Goodyear, L. J., and Kahn, B. B. (1998) Annu. Rev. Med. 49, 235-261[CrossRef][Medline] [Order article via Infotrieve] |
| 30. | Hayashi, T., Wojtaszewski, J. F. P., and Goodyear, L. J. (1997) Am. J. Physiol. 273, E1039-E1051 |
| 31. | Harmon, C. M., Luce, P., and Abumrad, N. A. (1992) Biochem. Soc. Trans. 20, 811-813[Medline] [Order article via Infotrieve] |
| 32. | Harmon, C. M., and Abumrad, N. A. (1993) J. Membr. Biol. 133, 43-49[Medline] [Order article via Infotrieve] |
| 33. |
Davis, R. J.,
Corvera, S.,
and Czech, M. P.
(1986)
J. Biol. Chem.
261,
8708-8711 |
| 34. | Tanner, L. I., and Lienhard, G. E. (1989) J. Biol. Chem. 264, 1537-1545 |
| 35. |
Abumrad, N. A.,
Perkins, R. C.,
Park, J. H.,
and Park, C. R.
(1981)
J. Biol. Chem.
256,
9183-9191 |
| 36. |
Stremmel, W.,
Strohmeyer, G.,
and Berk, P. D.
(1986)
Proc. Natl. Acad. Sci. U. S. A.
83,
3584-3588 |
| 37. | Stremmel, W. (1988) J. Clin. Invest. 81, 844-852 |
| 38. | McCullagh, K. J. A., Juel, C., O'Brien, M., and Bonen, A. (1996) Mol. Cell. Biochem. 156, 51-57[CrossRef][Medline] [Order article via Infotrieve] |
| 39. |
Ploug, T.,
Wojtaszewski, J.,
Kristiansen, S.,
Hespel, P.,
Galbo, H.,
and Richter, E. A.
(1993)
Am. J. Physiol.
264,
E270-E278 |
| 40. | Pelsers, M., Lutgerink, J. T., van Nieuwenhoven, F. A., Tandon, N. N., van der Vusse, G. J., Arends, J. W., Hoogenboom, H. R., and Glatz, J. F. C. (1999) Biochem. J. 337, 407-414 |
| 41. | Turcotte, L. P., Srivastava, A. K., and Chiasson, J.-L. (1997) Mol. Cell. Biochem. 166, 153-158[CrossRef][Medline] [Order article via Infotrieve] |
| 42. | Kiens, B., Kristiansen, S., Jensen, P., Richter, E. A., and Turcotte, L. P. (1997) Biochem. Biophys. Res. Commun. 231, 463-465[CrossRef][Medline] [Order article via Infotrieve] |
| 43. | Turcotte, L. P., Kiens, B., and Richter, E. A. (1991) FEBS Lett. 279, 327-329[CrossRef][Medline] [Order article via Infotrieve] |
| 44. |
Febbraio, M.,
Abumrad, N. A.,
Hajjar, D. P.,
Sharma, K.,
Cheng, W.,
Frieda, S.,
Pearce, A.,
and Silverstein, R. L.
(1999)
J. Biol. Chem.
274,
19055-19062 |
| 45. |
Hirsch, D.,
Stahl, A.,
and Lodish, H. F.
(1998)
Proc. Natl. Acad. Sci. U. S. A.
95,
8625-8629 |
| 46. | Glatz, J. F. C., and van der Vusse, G. J. (1996) Prog. Lipid Res. 35, 243-282[CrossRef][Medline] [Order article via Infotrieve] |
| 47. | White, M. F. (1997) Diabetologia 40, S2-S17 |
| 48. | Boden, G. (1996) Diabetes 45, 3-10 |
| 49. |
Richieri, G. V.,
Ogata, R. T.,
and Kleinfeld, A.
(1994)
J. Biol. Chem.
269,
23918-23930 |
Copyright © 2000 by The American Society for Biochemistry and Molecular Biology, Inc.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  G. R. Steinberg and B. E. Kemp AMPK in Health and Disease Physiol Rev, July 1, 2009; 89(3): 1025 - 1078. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. G. Nickerson, H. Alkhateeb, C. R. Benton, J. Lally, J. Nickerson, X.-X. Han, M. H. Wilson, S. S. Jain, L. A. Snook, J. F. C. Glatz, et al. Greater Transport Efficiencies of the Membrane Fatty Acid Transporters FAT/CD36 and FATP4 Compared with FABPpm and FATP1 and Differential Effects on Fatty Acid Esterification and Oxidation in Rat Skeletal Muscle J. Biol. Chem., June 12, 2009; 284(24): 16522 - 16530. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. J. Gurd, Y. Yoshida, J. Lally, G. P. Holloway, and A. Bonen The deacetylase enzyme SIRT1 is not associated with oxidative capacity in rat heart and skeletal muscle and its overexpression reduces mitochondrial biogenesis J. Physiol., April 15, 2009; 587(8): 1817 - 1828. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Bonen, X.-X. Han, N. N. Tandon, J. F. C. Glatz, J. Lally, L. A. Snook, and J. J. F. P. Luiken FAT/CD36 expression is not ablated in spontaneously hypertensive rats J. Lipid Res., April 1, 2009; 50(4): 740 - 748. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. P. Holloway, C. R. Benton, K. L. Mullen, Y. Yoshida, L. A. Snook, X.-X. Han, J. F. C. Glatz, J. J. F. P. Luiken, J. Lally, D. J. Dyck, et al. In obese rat muscle transport of palmitate is increased and is channeled to triacylglycerol storage despite an increase in mitochondrial palmitate oxidation Am J Physiol Endocrinol Metab, April 1, 2009; 296(4): E738 - E747. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Akki and A.-M. L. Seymour Western diet impairs metabolic remodelling and contractile efficiency in cardiac hypertrophy Cardiovasc Res, February 15, 2009; 81(3): 610 - 617. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. P Holloway, A. Bonen, and L. L Spriet Regulation of skeletal muscle mitochondrial fatty acid metabolism in lean and obese individuals Am. J. Clinical Nutrition, January 1, 2009; 89(1): 455S - 462S. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. P Turcotte and J. S Fisher Skeletal Muscle Insulin Resistance: Roles of Fatty Acid Metabolism and Exercise Physical Therapy, November 1, 2008; 88(11): 1279 - 1296. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. S. Mathai, A. Bonen, C. R. Benton, D. L. Robinson, and T. E. Graham Rapid exercise-induced changes in PGC-1{alpha} mRNA and protein in human skeletal muscle J Appl Physiol, October 1, 2008; 105(4): 1098 - 1105. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. W. Schwenk, J. J.F.P. Luiken, A. Bonen, and J. F.C. Glatz Regulation of sarcolemmal glucose and fatty acid transporters in cardiac disease Cardiovasc Res, July 15, 2008; 79(2): 249 - 258. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Smith, X. Su, R. El-Maghrabi, P. D. Stahl, and N. A. Abumrad Opposite Regulation of CD36 Ubiquitination by Fatty Acids and Insulin: EFFECTS ON FATTY ACID UPTAKE J. Biol. Chem., May 16, 2008; 283(20): 13578 - 13585. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. R. Benton, G. P. Holloway, S. E. Campbell, Y. Yoshida, N. N. Tandon, J. F. C. Glatz, J. J. J. F. P. Luiken, L. L. Spriet, and A. Bonen Rosiglitazone increases fatty acid oxidation and fatty acid translocase (FAT/CD36) but not carnitine palmitoyltransferase I in rat muscle mitochondria J. Physiol., March 15, 2008; 586(6): 1755 - 1766. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Pieter de Lange, M. Moreno, E. Silvestri, A. Lombardi, F. Goglia, and A. Lanni Fuel economy in food-deprived skeletal muscle: signaling pathways and regulatory mechanisms FASEB J, November 1, 2007; 21(13): 3431 - 3441. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. R. Soeters, H. P. Sauerwein, J. E. Groener, J. M. Aerts, M. T. Ackermans, J. F. C. Glatz, E. Fliers, and M. J. Serlie Gender-Related Differences in the Metabolic Response to Fasting J. Clin. Endocrinol. Metab., September 1, 2007; 92(9): 3646 - 3652. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X.-X. Han, A. Chabowski, N. N. Tandon, J. Calles-Escandon, J. F. C. Glatz, J. J. F. P. Luiken, and A. Bonen Metabolic challenges reveal impaired fatty acid metabolism and translocation of FAT/CD36 but not FABPpm in obese Zucker rat muscle Am J Physiol Endocrinol Metab, August 1, 2007; 293(2): E566 - E575. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Yoshida, G. P. Holloway, V. Ljubicic, H. Hatta, L. L. Spriet, D. A. Hood, and A. Bonen Negligible direct lactate oxidation in subsarcolemmal and intermyofibrillar mitochondria obtained from red and white rat skeletal muscle J. Physiol., August 1, 2007; 582(3): 1317 - 1335. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. P. Holloway, J. Lally, J. G. Nickerson, H. Alkhateeb, L. A. Snook, G. J. F. Heigenhauser, J. Calles-Escandon, J. F. C. Glatz, J. J. F. P. Luiken, L. L. Spriet, et al. Fatty acid binding protein facilitates sarcolemmal fatty acid transport but not mitochondrial oxidation in rat and human skeletal muscle J. Physiol., July 1, 2007; 582(1): 393 - 405. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Bonen, X.-X. Han, D. D. J. Habets, M. Febbraio, J. F. C. Glatz, and J. J. F. P. Luiken A null mutation in skeletal muscle FAT/CD36 reveals its essential role in insulin- and AICAR-stimulated fatty acid metabolism Am J Physiol Endocrinol Metab, June 1, 2007; 292(6): E1740 - E1749. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. P. Holloway, A. B. Thrush, G. J. F. Heigenhauser, N. N. Tandon, D. J. Dyck, A. Bonen, and L. L. Spriet Skeletal muscle mitochondrial FAT/CD36 content and palmitate oxidation are not decreased in obese women Am J Physiol Endocrinol Metab, June 1, 2007; 292(6): E1782 - E1789. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Fernstrom, L. Bakkman, M. Tonkonogi, I. G. Shabalina, Z. Rozhdestvenskaya, C. M. Mattsson, J. K. Enqvist, B. Ekblom, and K. Sahlin Reduced efficiency, but increased fat oxidation, in mitochondria from human skeletal muscle after 24-h ultraendurance exercise J Appl Physiol, May 1, 2007; 102(5): 1844 - 1849. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. L. Talanian, S. D. R. Galloway, G. J. F. Heigenhauser, A. Bonen, and L. L. Spriet Two weeks of high-intensity aerobic interval training increases the capacity for fat oxidation during exercise in women J Appl Physiol, April 1, 2007; 102(4): 1439 - 1447. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. S. Eyre, L. G. Cleland, N. N. Tandon, and G. Mayrhofer Importance of the carboxyl terminus of FAT/CD36 for plasma membrane localization and function in long-chain fatty acid uptake J. Lipid Res., March 1, 2007; 48(3): 528 - 542. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Bonen, A. Chabowski, J. J. F. P Luiken, and J. F. C. Glatz Mechanisms and Regulation of Protein-Mediated Cellular Fatty Acid Uptake: Molecular, Biochemical, and Physiological Evidence Physiology, February 1, 2007; 22(1): 15 - 28. [Full Text] [PDF]
|
|
|
|
|
|
D. Bishop, J. Edge, C. Thomas, and J. Mercier High-intensity exercise acutely decreases the membrane content of MCT1 and MCT4 and buffer capacity in human skeletal muscle J Appl Physiol, February 1, 2007; 102(2): 616 - 621. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Sahlin, M. Mogensen, M. Bagger, M. Fernstrom, and P. K. Pedersen The potential for mitochondrial fat oxidation in human skeletal muscle influences whole body fat oxidation during low-intensity exercise Am J Physiol Endocrinol Metab, January 1, 2007; 292(1): E223 - E230. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Enoki, Y. Yoshida, J. Lally, H. Hatta, and A. Bonen Testosterone increases lactate transport, monocarboxylate transporter (MCT) 1 and MCT4 in rat skeletal muscle J. Physiol., November 15, 2006; 577(1): 433 - 443. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Fosgerau, C. Fledelius, K. E Pedersen, J. B Kristensen, J. R Daugaard, M. A Iglesias, E. W Kraegen, and S. M Furler Oral administration of glucose promotes intracellular partitioning of fatty acid toward storage in white but not in red muscle. J. Endocrinol., September 1, 2006; 190(3): 651 - 658. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Chabowski, J. C. Chatham, N. N. Tandon, J. Calles-Escandon, J. F. C. Glatz, J. J. F. P. Luiken, and A. Bonen Fatty acid transport and FAT/CD36 are increased in red but not in white skeletal muscle of ZDF rats Am J Physiol Endocrinol Metab, September 1, 2006; 291(3): E675 - E682. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Schenk and J. F. Horowitz Coimmunoprecipitation of FAT/CD36 and CPT I in skeletal muscle increases proportionally with fat oxidation after endurance exercise training Am J Physiol Endocrinol Metab, August 1, 2006; 291(2): E254 - E260. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. B. Jorgensen, E. A. Richter, and J. F. P. Wojtaszewski Role of AMPK in skeletal muscle metabolic regulation and adaptation in relation to exercise J. Physiol., July 1, 2006; 574(1): 17 - 31. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. R. Benton, D. P. Y. Koonen, J. Calles-Escandon, N. N. Tandon, J. F. C. Glatz, J. J. F. P. Luiken, J. J. Heikkila, and A. Bonen Differential effects of contraction and PPAR agonists on the expression of fatty acid transporters in rat skeletal muscle J. Physiol., May 15, 2006; 573(1): 199 - 210. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Q. Wu, A. M. Ortegon, B. Tsang, H. Doege, K. R. Feingold, and A. Stahl FATP1 Is an Insulin-Sensitive Fatty Acid Transporter Involved in Diet-Induced Obesity. Mol. Cell. Biol., May 1, 2006; 26(9): 3455 - 3467. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. Bezaire, C. R. Bruce, G. J. F. Heigenhauser, N. N. Tandon, J. F. C. Glatz, J. J. J. F. Luiken, A. Bonen, and L. L. Spriet Identification of fatty acid translocase on human skeletal muscle mitochondrial membranes: essential role in fatty acid oxidation Am J Physiol Endocrinol Metab, March 1, 2006; 290(3): E509 - E515. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. P. Holloway, V. Bezaire, G. J. F. Heigenhauser, N. N. Tandon, J. F. C. Glatz, J. J. F. P. Luiken, A. Bonen, and L. L. Spriet Mitochondrial long chain fatty acid oxidation, fatty acid translocase/CD36 content and carnitine palmitoyltransferase I activity in human skeletal muscle during aerobic exercise J. Physiol., February 15, 2006; 571(1): 201 - 210. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. R. Benton, X.-X. Han, M. Febbraio, T. E. Graham, and A. Bonen Inverse relationship between PGC-1{alpha} protein expression and triacylglycerol accumulation in rodent skeletal muscle J Appl Physiol, February 1, 2006; 100(2): 377 - 383. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Kiens Skeletal Muscle Lipid Metabolism in Exercise and Insulin Resistance Physiol Rev, January 1, 2006; 86(1): 205 - 243. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. W. Zderic and M. T. Hamilton Physical inactivity amplifies the sensitivity of skeletal muscle to the lipid-induced downregulation of lipoprotein lipase activity J Appl Physiol, January 1, 2006; 100(1): 249 - 257. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. L. M. Coort, W. A. Coumans, A. Bonen, G. J. van der Vusse, J. F. C. Glatz, and J. J. F. P. Luiken Divergent effects of rosiglitazone on protein-mediated fatty acid uptake in adipose and in muscle tissues of Zucker rats J. Lipid Res., June 1, 2005; 46(6): 1295 - 1302. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Garcia-Martinez, M. Marotta, R. Moore-Carrasco, M. Guitart, M. Camps, S. Busquets, E. Montell, and A. M. Gomez-Foix Impact on fatty acid metabolism and differential localization of FATP1 and FAT/CD36 proteins delivered in cultured human muscle cells Am J Physiol Cell Physiol, June 1, 2005; 288(6): C1264 - C1272. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Schenk, J. N. Cook, A. E. Kaufman, and J. F. Horowitz Postexercise insulin sensitivity is not impaired after an overnight lipid infusion Am J Physiol Endocrinol Metab, March 1, 2005; 288(3): E519 - E525. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Raney, A. J. Yee, M. K. Todd, and L. P. Turcotte AMPK activation is not critical in the regulation of muscle FA uptake and oxidation during low-intensity muscle contraction Am J Physiol Endocrinol Metab, March 1, 2005; 288(3): E592 - E598. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Pohl, A. Ring, U. Korkmaz, R. Ehehalt, and W. Stremmel FAT/CD36-mediated Long-Chain Fatty Acid Uptake in Adipocytes Requires Plasma Membrane Rafts Mol. Biol. Cell, January 1, 2005; 16(1): 24 - 31. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Fink, L. Abildtrup, K. Fogd, B. M. Abdallah, M. Kassem, P. Ebbesen, and V. Zachar Induction of Adipocyte-Like Phenotype in Human Mesenchymal Stem Cells by Hypoxia Stem Cells, December 1, 2004; 22(7): 1346 - 1355. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Coles, J. Litt, H. Hatta, and A. Bonen Exercise rapidly increases expression of the monocarboxylate transporters MCT1 and MCT4 in rat muscle J. Physiol., November 15, 2004; 561(1): 253 - 261. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Kiens, C. Roepstorff, J. F. C. Glatz, A. Bonen, P. Schjerling, J. Knudsen, and J. N. Nielsen Lipid-binding proteins and lipoprotein lipase activity in human skeletal muscle: influence of physical activity and gender J Appl Physiol, October 1, 2004; 97(4): 1209 - 1218. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Heron-Milhavet, M. Haluzik, S. Yakar, O. Gavrilova, S. Pack, W. C. Jou, A. Ibrahimi, H. Kim, D. Hunt, D. Yau, et al. Muscle-Specific Overexpression of CD36 Reverses the Insulin Resistance and Diabetes of MKR Mice Endocrinology, October 1, 2004; 145(10): 4667 - 4676. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Roepstorff, B. Vistisen, K. Roepstorff, and B. Kiens Regulation of plasma long-chain fatty acid oxidation in relation to uptake in human skeletal muscle during exercise Am J Physiol Endocrinol Metab, October 1, 2004; 287(4): E696 - E705. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Chabowski, S. L. M. Coort, J. Calles-Escandon, N. N. Tandon, J. F. C. Glatz, J. J. F. P. Luiken, and A. Bonen Insulin stimulates fatty acid transport by regulating expression of FAT/CD36 but not FABPpm Am J Physiol Endocrinol Metab, October 1, 2004; 287(4): E781 - E789. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. E. Campbell, N. N. Tandon, G. Woldegiorgis, J. J. F. P. Luiken, J. F. C. Glatz, and A. Bonen A Novel Function for Fatty Acid Translocase (FAT)/CD36: INVOLVEMENT IN LONG CHAIN FATTY ACID TRANSFER INTO THE MITOCHONDRIA J. Biol. Chem., August 27, 2004; 279(35): 36235 - 36241. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. A. Iglesias, S. M. Furler, G. J. Cooney, E. W. Kraegen, and J.-M. Ye AMP-Activated Protein Kinase Activation by AICAR Increases Both Muscle Fatty Acid and Glucose Uptake in White Muscle of Insulin-Resistant Rats In Vivo Diabetes, July 1, 2004; 53(7): 1649 - 1654. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. L.M. Coort, D. M. Hasselbaink, D. P.Y. Koonen, J. Willems, W. A. Coumans, A. Chabowski, G. J. van der Vusse, A. Bonen, J. F.C. Glatz, and J. J.F.P. Luiken Enhanced Sarcolemmal FAT/CD36 Content and Triacylglycerol Storage in Cardiac Myocytes From Obese Zucker Rats Diabetes, July 1, 2004; 53(7): 1655 - 1663. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. P. Y. Koonen, C. R. Benton, Y. Arumugam, N. N. Tandon, J. Calles-Escandon, J. F. C. Glatz, J. J. F. P. Luiken, and A. Bonen Different mechanisms can alter fatty acid transport when muscle contractile activity is chronically altered Am J Physiol Endocrinol Metab, June 1, 2004; 286(6): E1042 - E1049. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Vistisen, K. Roepstorff, C. Roepstorff, A. Bonen, B. van Deurs, and B. Kiens Sarcolemmal FAT/CD36 in human skeletal muscle colocalizes with caveolin-3 and is more abundant in type 1 than in type 2 fibers J. Lipid Res., April 1, 2004; 45(4): 603 - 609. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. C. Clarke, D. Miskovic, X.-X. Han, J. Calles-Escandon, J. F. C. Glatz, J. J. F. P. Luiken, J. J. Heikkila, and A. Bonen Overexpression of membrane-associated fatty acid binding protein (FABPpm) in vivo increases fatty acid sarcolemmal transport and metabolism Physiol Genomics, March 12, 2004; 17(1): 31 - 37. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. G. Richards, A. Bonen, G. J. F. Heigenhauser, and C. M. Wood Palmitate movement across red and white muscle membranes of rainbow trout Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2004; 286(1): R46 - R53. [Abstract] [Full Text]
|
|
|
|
|
|
M. Z. Tucker and L. P. Turcotte Aging is associated with elevated muscle triglyceride content and increased insulin-stimulated fatty acid uptake Am J Physiol Endocrinol Metab, October 1, 2003; 285(4): E827 - E835. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. N. Black and C. C. DiRusso Transmembrane Movement of Exogenous Long-Chain Fatty Acids: Proteins, Enzymes, and Vectorial Esterification Microbiol. Mol. Biol. Rev., September 1, 2003; 67(3): 454 - 472. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Binas, X.-X. Han, E. Erol, J. J. F. P. Luiken, J. F. C. Glatz, D. J. Dyck, R. Motazavi, P. J. Adihetty, D. A. Hood, and A. Bonen A null mutation in H-FABP only partially inhibits skeletal muscle fatty acid metabolism Am J Physiol Endocrinol Metab, September 1, 2003; 285(3): E481 - E489. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Wang, M. Tonouchi, D. Miskovic, H. Hatta, and A. Bonen T3 increases lactate transport and the expression of MCT4, but not MCT1, in rat skeletal muscle Am J Physiol Endocrinol Metab, September 1, 2003; 285(3): E622 - E628. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J. Watt, G. R. Steinberg, G. J. F. Heigenhauser, L. L. Spriet, and D. J. Dyck Hormone-sensitive lipase activity and triacylglycerol hydrolysis are decreased in rat soleus muscle by cyclopiazonic acid Am J Physiol Endocrinol Metab, August 1, 2003; 285(2): E412 - E419. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J.F.P. Luiken, S. L.M. Coort, J. Willems, W. A. Coumans, A. Bonen, G. J. van der Vusse, and J. F.C. Glatz Contraction-Induced Fatty Acid Translocase/CD36 Translocation in Rat Cardiac Myocytes Is Mediated Through AMP-Activated Protein Kinase Signaling Diabetes, July 1, 2003; 52(7): 1627 - 1634. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Irie, I. B. Krukenkamp, J. F. F. Brinkmann, G. R. Gaudette, A. E. Saltman, W. Jou, J. F. C. Glatz, N. A. Abumrad, and A. Ibrahimi Myocardial recovery from ischemia is impaired in CD36-null mice and restored by myocyte CD36 expression or medium-chain fatty acids PNAS, May 27, 2003; 100(11): 6819 - 6824. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. H. A. G. M. van der Putten, E. C. H. Friesema, N. A. Abumrad, M. E. Everts, and T. J. Visser Thyroid Hormone Transport by the Rat Fatty Acid Translocase Endocrinology, April 1, 2003; 144(4): 1315 - 1323. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J. F. P. Luiken, Y. Arumugam, R. C. Bell, J. Calles-Escandon, N. N. Tandon, J. F. C. Glatz, and A. Bonen Changes in fatty acid transport and transporters are related to the severity of insulin deficiency Am J Physiol Endocrinol Metab, September 1, 2002; 283(3): E612 - E621. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Z. Tucker and L. P. Turcotte Brief food restriction increases FA oxidation and glycogen synthesis under insulin-stimulated conditions Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2002; 282(4): R1210 - R1218. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. R. Steinberg, D. J. Dyck, J. Calles-Escandon, N. N. Tandon, J. J. F. P. Luiken, J. F. C. Glatz, and A. Bonen Chronic Leptin Administration Decreases Fatty Acid Uptake and Fatty Acid Transporters in Rat Skeletal Muscle J. Biol. Chem., March 8, 2002; 277(11): 8854 - 8860. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. E. Schaffer Fatty acid transport: the roads taken Am J Physiol Endocrinol Metab, February 1, 2002; 282(2): E239 - E246. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J. F. P. Luiken, D. J. Dyck, X.-X. Han, N. N. Tandon, Y. Arumugam, J. F. C. Glatz, and A. Bonen Insulin induces the translocation of the fatty acid transporter FAT/CD36 to the plasma membrane Am J Physiol Endocrinol Metab, February 1, 2002; 282(2): E491 - E495. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. P. Turcotte, J. R. Swenberger, and A. J. Yee High carbohydrate availability increases LCFA uptake and decreases LCFA oxidation in perfused muscle Am J Physiol Endocrinol Metab, January 1, 2002; 282(1): E177 - E183. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J. F. P. Luiken, J. Willems, G. J. van der Vusse, and J. F. C. Glatz Electrostimulation enhances FAT/CD36-mediated long-chain fatty acid uptake by isolated rat cardiac myocytes Am J Physiol Endocrinol Metab, October 1, 2001; 281(4): E704 - E712. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. E. Campbell, D. J. Angus, and M. A. Febbraio Glucose kinetics and exercise performance during phases of the menstrual cycle: effect of glucose ingestion Am J Physiol Endocrinol Metab, October 1, 2001; 281(4): E817 - E825. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. J C van Loon, P. L Greenhaff, D Constantin-Teodosiu, W. H M Saris, and A. J M Wagenmakers The effects of increasing exercise intensity on muscle fuel utilisation in humans J. Physiol., October 1, 2001; 536(1): 295 - 304. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. J. Dyck, G. Steinberg, and A. Bonen Insulin increases FA uptake and esterification but reduces lipid utilization in isolated contracting muscle Am J Physiol Endocrinol Metab, September 1, 2001; 281(3): E600 - E607. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J. F. P. Luiken, Y. Arumugam, D. J. Dyck, R. C. Bell, M. M. L. Pelsers, L. P. Turcotte, N. N. Tandon, J. F. C. Glatz, and A. Bonen Increased Rates of Fatty Acid Uptake and Plasmalemmal Fatty Acid Transporters in Obese Zucker Rats J. Biol. Chem., October 26, 2001; 276(44): 40567 - 40573. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. R. Steinberg, A. Bonen, and D. J. Dyck Fatty acid oxidation and triacylglycerol hydrolysis are enhanced after chronic leptin treatment in rats Am J Physiol Endocrinol Metab, March 1, 2002; 282(3): E593 - E600. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Tonouchi, H. Hatta, and A. Bonen Muscle contraction increases lactate transport while reducing sarcolemmal MCT4, but not MCT1 Am J Physiol Endocrinol Metab, May 1, 2002; 282(5): E1062 - E1069. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| All ASBMB Journals | Molecular and Cellular Proteomics |
| Journal of Lipid Research | ASBMB Today |