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J. Biol. Chem., Vol. 275, Issue 49, 38176-38181, December 8, 2000
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From the a Amyloid Unit, Instituto de Biologia
Molecular e Celular and the b Instituto de Ciências
Biomédicas Abel Salazar, University of Porto, Porto 4150, Portugal, the d Department of Clinical Biochemistry,
Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QR, United
Kingdom, the Departments of e Medical Biochemistry and
g Cell Biology, University of Aarhus, 8000 Aarhus C,
Denmark, the f Max-Delbrueck Center for Molecular Medicine,
13125 Berlin, Germany, the h Molecular Endocrinology Group,
Nuffield Department of Medicine, University of Oxford,
Oxford OX3 9DU, United Kingdom, and the i INSERM, U489,
Hôpital Tenon, F-75020 Paris, France
Received for publication, April 5, 2000, and in revised form, July 21, 2000
The kidney is a major organ for
uptake of the thyroid hormone thyroxine (T4) and its
conversion to the active form, triiodothyronine. In the plasma,
one of the T4 carriers is transthyretin (TTR). In the
present study we observed that TTR, the transporter of both
T4 and retinol-binding protein, binds to megalin, the
multiligand receptor expressed on the luminal surface of various
epithelia including the renal proximal tubules. In the kidney, megalin
plays an important role in tubular uptake of macromolecules filtered through the glomerulus. To evaluate the importance of megalin for renal
uptake of TTR, we performed binding/uptake assays using immortalized
rat yolk sac cells with high expression levels of megalin. Radiolabeled
TTR, free as well as in complex with thyroxine or retinol-binding
protein, was rapidly taken up by the cells, and the uptake was strongly
inhibited by a polyclonal megalin antibody and by the
receptor-associated protein, a chaperone-like protein inhibiting ligand
binding to megalin. In cell culture, different TTR mutations presented
different levels of cell association and degradation, suggesting that
the structure of TTR is important for megalin recognition. Both the apo
form and the T4-bound form were taken up by the cells.
Analysis of urine from patients with Dent's disease, a renal tubular
disorder that alters receptor-mediated endocytic reabsorption of
proteins, identified TTR as an abundant excreted protein. Furthermore,
analysis of kidney sections of megalin-deficient mice revealed no
immunohistochemical TTR labeling in intracellular vesicles in the
proximal tubule cells when compared with wild type control littermates.
Taken together, the present data indicate that TTR represents a novel
megalin ligand of importance in the thyroid hormone homeostasis.
Proximal tubules of the kidney serve an important function for the
uptake of macromolecules passing the glomerular filtration barrier.
Therefore, despite the massive influx of protein in the proximal
tubules, human urine is virtually devoid of significant amounts of
protein. By this way the proximal tubules salvage amino acids and
essential protein-bound components such as lipids, hormones, and vitamins.
The receptor megalin plays an important role in the reuptake mechanism.
Megalin is a multiligand endocytic receptor expressed in
clathrin-coated pits at the apical surface of a number of absorptive epithelia, including those of the proximal tubule (1) and yolk sac (2).
Megalin is a member of the low density lipoprotein receptor family (3)
and binds, as do the other members of this family, the ~40-kDa
receptor-associated protein
(RAP)1 (4), which functions
as a specialized chaperone/escort protein during the biosynthesis of
some of the members of the low density lipoprotein receptor family and
in their delivery to the cell surface (5, 6).
Megalin ligands include vitamin carriers known to be filtered, such as
transcobalamin (vitamin B12-binding protein) (7), vitamin
D-binding protein (8), and retinol-binding protein (RBP) (9). The
general importance of megalin was supported by the findings that
knockout mice for the megalin gene result in high mortality,
developmental abnormalities (10), and tubular reabsorption deficiency
with excretion of low molecular weight plasma proteins in the urine
(low molecular weight proteinuria) (11).
In the plasma, holo-RBP strongly interacts with transthyretin (TTR),
and approximately 50% of TTR circulates as a 1:1 molar TTR·RBP complex (12). The formation of the TTR·RBP complex
prevents to a certain extent the RBP·retinol complex from being
filtered in the glomeruli. However, 4-5% of the circulating
RBP·retinol is not bound to TTR (13) and is taken up by means of
megalin in the proximal tubule (9). Apart from transporting retinol via
binding to RBP, plasma TTR, a tetramer of four identical subunits of
approximately 14 kDa (14), acts as a transport protein for the thyroid
hormone thyroxine (T4). Most, if not all, of the active form of T4, triiodothyronine, is generated by deiodination
of T4 mainly in the liver and in the proximal tubules of
the kidney (15).
Despite no detection of TTR mRNA in the adult kidney (16), which is
one of the major extrahepatic sites of TTR degradation (18), positive
staining was reported in the epithelium of the renal proximal tubules
(17). However, the mechanism of TTR internalization and
degradation remains to be elucidated, although a receptor-mediated uptake has been suggested (19). Because megalin has been implicated in
the renal reuptake of plasma proteins that carry lipophilic compounds,
we investigated the possibility that this receptor might also play a
role in renal uptake of TTR.
Proteins and Antibodies--
Recombinant TTR was purified from
Escherichia coli D1210 transformed with plasmids carrying
either wild type TTR (pINTRwt) or the suitable mutant TTR cDNA
(pINTR30 and pINTR119) according to Almeida et al. (20).
Serum RBP was isolated by affinity in a TTR column and saturated with a
molar excess of all-trans retinol (Sigma) by incubation at
37 °C in the dark for 1 h; excess retinol was separated from
RBP by gel filtration in 10-ml Biogel P-6 DG columns (Bio-Rad).
Recombinant RAP was expressed and purified as described previously
(21). Megalin was purified by RAP affinity chromatography from human
kidney cortex according to standard procedures (22). Purified sheep
polyclonal antibodies against rat megalin have been described, and
their specificity has been characterized (7). Purified sheep non-immune
IgG was used as a negative control in binding experiments.
Protein Iodination--
TTR and RAP were iodinated following the
iodogen method. Briefly, to reaction tubes coated with 10 µg of
iodogen (Sigma), 100 µl of 0.25 M phosphate buffer and 1 mCi (37 MBq) of Na125I (Amersham Pharmacia Biotech)
were added, followed by 10 µg of protein in phosphate-buffered saline
(PBS). The reaction was allowed to proceed in an ice bath for 10 min.
Labeled protein was separated from free iodide in a 5-ml Sephadex G50
column (Amersham Pharmacia Biotech). For TTR, specific activities were
determined after each iodination by a quantitative enzyme-linked
immunosorbent assay using polyclonal anti-human TTR (Dako) as
the coating antibody and peroxidase-conjugated anti-human TTR (The
Binding Site) as secondary antibody. 125I-labeled
TTR (125I-TTR) concentration was calculated from a standard
curve ranging from 5 to 200 ng/ml. Characteristic specific activities
were of 104 cpm/ng.
125I-TTR·RBP and
125I-TTR·T4 Complex
Formation--
125I-TTR was complexed with RBP by
incubation with a 1:4 molar ratio of TTR:RBP for 2 h at 37 °C
in the dark. 125I-TTR was complexed to T4 by
incubation with a molar excess of the hormone in TNE buffer (1 M Tris-HCl pH 8.0, 0.1 M NaCl, and 1 mM EDTA). Free hormone was removed by gel filtration in
1-ml Sephadex LH20 columns (Sigma) equilibrated in TNE buffer.
Uptake of TTR in Cultured Yolk Sac Cells--
Megalin-expressing
Brown Norway Rat yolk sac epithelial cells transformed with mouse
sarcoma virus (BN cells) (24) were grown to confluence in 24-well
plates (Nunc A/S) in Dulbecco's modified Eagle's medium
containing 10% (v/v) fetal calf serum, 100 units/ml penicillin, and
100 µg/ml streptomycin. Before incubation cells were washed with
ice-cold PBS. Incubation with 125I-TTR was carried out in
serum-free Dulbecco's modified Eagle's medium supplemented with 0.1%
(w/v) ovalbumin for the indicated periods of time, either at 4 or
37 °C. In some experiments 125I-TTR was added in the
presence of RAP (1 µM), IgG antibody against megalin (200 µg/ml), IgG antibody against cubilin (200 µg/ml), or sheep
non-immune IgG (200 µg/ml). Degradation of labeled protein was
measured by precipitation of the incubation medium in 10% trichloroacetic acid. In all experiments, a control was included in
which the amount of degradation was assessed in the absence of cells.
Cell-associated radioactivity was determined by measuring radioactivity
of the washed cell layer in ice-cold PBS followed by cell
solubilization in 0.1 M NaOH. Total cellular protein was measured with the Bio-Rad protein assay kit (Bio-Rad), using bovine serum albumin as a standard. Cell association of 125I-TTR
measured at a saturating concentration of unlabeled ligand (1 mg/ml)
was considered nonspecific and subtracted from all values.
Ligand and Immunoblotting of BN Cells--
Ligand and
immunoblotting were performed essentially as described (7). Briefly, BN
cells were subjected to SDS-polyacrylamide gel electrophoresis
(4-16%) and electroblotted onto Immobilon membranes (Millipore).
Membrane strips were incubated with radiolabeled RAP (3 × 103 Bq/ml) in 10 mM Hepes, 140 mM
NaCl, 2 mM CaCl2, 1 mM
MgCl2, and 1% bovine serum albumin (pH 7.8). Similar
strips used for immunoblotting were blocked in 2% nonfat dry milk and
0.05% Tween 20 in the Hepes buffer and subsequently incubated with
antibody in the Hepes buffer with 0.2% nonfat dry milk. Sheep anti-rat
megalin antibody was used at a dilution of 1:10,000.
Surface Plasmon Resonance (SPR) Analysis--
Receptor-ligand
interactions were assessed by SPR analysis on a BIAcore 2000 instrument (Biacore) as described (25). Megalin was immobilized onto a
CM5 sensor chip, using the amine-coupling kit as described by the
supplier, at indicated densities. A control channel was routinely
activated and blocked in the absence of protein. Binding to coated
channels was corrected for binding to noncoated channels. SPR analysis
was assessed in 150 mM NaCl, 2 mM
CaCl2, 0.005% (v/v) Tween 20, and 20 mM Hepes
(pH 7.4) at 20 °C.
Preparation of Renal Tissue--
Megalin-deficient mice were
produced by gene targeting as described (11). Wild type littermates
were used as controls. Mouse megalin knockout and control kidneys were
fixed by perfusion through the heart with 4% paraformaldehyde in 0.1 M sodium cacodylate buffer. The tissue was trimmed into
small blocks, further fixed by immersion for 1 h in 1%
paraformaldehyde, infiltrated with 2.3 M sucrose containing
2% paraformaldehyde for 30 min, and frozen in liquid nitrogen.
Immunohistochemistry--
For light microscopy, 0.8-µm
cryosections were obtained at Urine Samples--
Overnight urine samples from six patients
with Fanconi syndrome, four of whom had Dent's disease (27) due to
mutations of the renal chloride channel (28), and from three healthy
control subjects were refrigerated immediately after collection and
stored at SDS-Polyacrylamide Gel Electrophoresis of Urine
Samples--
10-µl urine samples were electrophoresed in 8-16%
SDS-polyacrylamide gel electrophoresis gels and subsequently
transferred to nitrocellulose. Blots were blocked in 5% milk in PBS
containing 0.1% Tween 20 for 1 h and incubated for 1 h at
room temperature with anti-human TTR (Dako) in PBS containing 0.1%
Tween 20. After washing in PBS containing 0.1% Tween 20, blots were
incubated for 1 h with alkaline phosphatase-conjugated anti-rabbit
IgG (Dako). Antibody binding was visualized using nitro blue
tetrazolium and 5-bromo-1-chloro-3-indolyl phosphate color development
substrates (Promega).
To investigate the hypothesis that megalin might be responsible
for the tubular uptake of T4 by internalizing TTR, we
analyzed TTR binding/uptake using an established immortalized rat yolk sac epithelial cell line with high expression of megalin (24). 125I-TTR bound efficiently and in a saturable manner to the
cells at 4 °C (Fig. 1a),
consistent with the existence of a TTR receptor. The apparent
Kd for the 4 °C, 4-h binding to the cells was
estimated to be approximately 500 nM when assuming one
class of binding sites (Fig. 1b). 125I-TTR was
rapidly taken up, and in accordance with an endocytic process,
radiolabeled degradation products appeared in the medium after a lag
time of approximately 30 min (Fig. 1c). Saturating concentrations of polyclonal antibodies against megalin showed a 63%
inhibition in uptake, whereas no significant effect was seen with
anti-cubilin antibody nor with nonimmune IgG (Fig.
2a). Cubilin, an apical
receptor expressed in the same tissues as megalin (29), is another
apical receptor present in the BN cell line. The absence of significant
inhibition of TTR uptake by the anti-cubilin antibody rules out the
possibility of a nonspecific steric effect produced by the anti-megalin
antibody that could be responsible for the observed inhibition of TTR
uptake. Therefore, the BN cell line presents specific megalin-mediated
TTR degradation.
A strong inhibition in uptake was also observed with RAP (67%) (Fig.
2a). These data further suggest that the mechanism of TTR uptake presents features of a low density lipoprotein
receptor-mediated mechanism, namely, RAP sensitivity. BN cells were
analyzed under non-reducing conditions by anti-megalin
immunoblotting and ligand blotting with radiolabeled RAP (Fig.
2b). The only RAP-binding protein observed was megalin, thus
showing that in the BN cells, megalin is the prime RAP-binding
receptor. Although these cells express cubilin, which has modest
affinity for RAP, the involvement of this receptor in TTR
internalization had been ruled out by competition experiments using the
anti-cubilin antibody as described above.
SPR (data not shown) confirmed binding of purified TTR to immobilized
megalin with an approximate Kd of 5 µM
at 20 °C, comparable with the low affinity of the interaction of RBP and megalin (9). The influence of T4 on TTR binding to
megalin could not be assessed by SPR due to the well known
hydrophobicity of the hormone, resulting in nonspecific binding to the
SPR sensor chip.
The influence of TTR ligands on the interaction of the protein with
megalin was further studied by uptake experiments of
125I-TTR complexed with either RBP or T4 in the
rat yolk sac epithelial cell line. No significant difference was
observed, however, by the presence of TTR ligands on the degradation
and cellular association of TTR (Fig.
3a).
Evidence for the Role of Megalin in Renal Uptake of
Transthyretin*
ABSTRACT
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ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
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DISCUSSION
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INTRODUCTION
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ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS
DISCUSSION
REFERENCES
EXPERIMENTAL PROCEDURES
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ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS
DISCUSSION
REFERENCES
80 °C with an FCS Reichert
Ultracut cryoultramicrotome as described previously (1). For
immunolabeling, the sections were incubated with rabbit anti-rat TTR
primary antibody (26), diluted 1:200, at room temperature for
1 h after preincubation in PBS containing 0.05 M
glycine and 1% bovine serum albumin. The sections were subsequently
incubated with peroxidase-conjugated secondary antibodies (Dako), and
the peroxidase was visualized with diaminobenzidine. As control,
sections were incubated with secondary antibodies alone or with
nonspecific rabbit IgG. The sections were subsequently counterstained
with Meier's stain for 2 min and examined in a Leica DMR
microscope equipped with a Sony 3CCD color video camera attached to a
Sony Digital still recorder. Images were processed using Adobe
Photoshop 4.0.
80 °C until processed for immunoblotting.
RESULTS
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EXPERIMENTAL PROCEDURES
RESULTS
DISCUSSION
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View larger version (9K):
[in a new window]
Fig. 1.
Cell association, uptake, and degradation of
125I-TTR in cultured rat yolk sac cells. a,
saturation curves for cell association of 125I-TTR in rat
yolk sac epithelial cells at 4 °C for 4 h. Horizontal
axes, concentration of unlabeled ligand plus
125I-TTR-labeled ligand. The values presented represent the
mean ± S.D. b, Scatchard plot of the 13.4-201 µg
TTR/ml values represented in a. c, time course
for cell association of 125I-TTR ( 
) and increase in
trichloroacetic acid-soluble 125I-labeled
degradation products (
) in the medium at 37 °C.
View larger version (29K):
[in a new window]
Fig. 2.
a, cell association and degradation of
125I-TTR in cultured rat yolk sac cells. Cell association
(filled bars) and degradation (striped bars) were
assessed after 2 h at 37 °C in the presence of RAP (1 µM), IgG antibody against megalin or cubilin (200 µg/ml), and sheep non-immune IgG (200 µg/ml). The data represent
percents of control values (incubation of 125I-TTR plus
buffer alone); the values presented represent the mean ± S.D. of
triplicate determinations. Control incubation (100%) values were
similar to the 2-h values in Fig. 1b. b,
anti-megalin immunoblotting (lane 1) and RAP ligand blotting
(lane 2) of BN cells.
View larger version (18K):
[in a new window]
Fig. 3.
a, influence of TTR ligands, RBP, and
T4 on the uptake of 125I-TTR in cultured rat
yolk sac cells. Cell association (filled bars) and
degradation (striped bars) of 125I-TTR,
125I-TTR complexed with RBP (TTR-RBP), and
125I-TTR complexed with T4 (TTR-T4), measured
after 2 h of incubation at 37 °C. b, influence of
TTR mutations on uptake of 125I-TTR in cultured rat yolk
sac cells. Increase of trichloroacetic acid-soluble
125I-labeled degradation products in the medium at
37 °C of 125I-TTR wild type ( ), 125I-TTR
V30M (
), and 125I-TTR T119M ().
Several point mutations in TTR have been described (30), and most of them are associated with the occurrence of familial amyloidotic polyneuropathy, a disease characterized by the extracellular deposition of TTR amyloid fibrils in various tissues (31). To study the influence of TTR mutations on the uptake by megalin, we tested TTR V30M, an amyloidogenic mutant, and TTR T199M, a non-amyloidogenic variant. The uptake of the different TTRs was corrected for their specific activities. TTR V30M was the mutant with the highest uptake, whereas TTR T119M was the variant with the lowest uptake (Fig. 3b). These data suggested that the conformation of TTR influences the recognition by megalin.
To evaluate the physiological importance of an endocytic mechanism for
TTR uptake in the proximal tubules, we analyzed the urine of patients
with Fanconi syndrome and Dent's disease. Dent's disease is known to
be associated with tubular failure, which is probably caused by a
defect in receptor-mediated endocytosis in the proximal tubules. The
molecular basis of this disorder has been defined to be due to
inactivating chloride channel 5 (CLC-5) mutations (28). Furthermore
CLC-5 has been shown to be present in the early endosomes of the
receptor-mediated tubular endocytic pathway, in which megalin is the
prime receptor (32). Western blotting analysis clearly identified TTR
in the urine of patients with Fanconi syndrome, whereas it was absent
in control individuals (Fig. 4). This
suggested that in vivo TTR might be taken up in the proximal
tubules by an endocytic mechanism.
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To further demonstrate that the receptor responsible for tubular uptake
of TTR in vivo is megalin, we compared proximal
tubules of megalin knockout mice and control animals by TTR
immunohistochemistry. Light microscope immunohistochemistry
revealed a granular staining pattern for TTR in renal proximal
tubules of control mice (Fig. 5a). The staining was observed
only in segment 1 of the proximal tubule and probably only the initial
part of segment 1, indicating that the protein under physiological
conditions is removed very efficiently in the early part of the
proximal tubule after glomerular filtration. Megalin-deficient mice
(Fig. 5b) presented no staining in kidneys, suggesting
absence of TTR uptake in the proximal tubules. In both wild type and
knockout animals, erythrocytes were stained because of endogenous
peroxidase activity (Fig. 5). The absence of TTR vesicular labeling in
the proximal tubules of megalin-deficient mice demonstrates that these
animals lack the endocytic mechanism of TTR tubular uptake present in
the control animals. TTR therefore represents a novel megalin
ligand.
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The present study reveals that megalin is a receptor for tubular uptake of TTR. Megalin interaction with TTR was demonstrated in vitro by SPR analysis and by uptake studies of 125I-TTR in cells with high expression levels of megalin. Although the affinity of TTR for this receptor is relatively low, it is the same order of magnitude previously reported for other megalin ligands (11). Further evidence pointing to the in vivo relevance of this interaction came from the observations that patients with renal tubule failure excrete TTR in the urine and also that megalin knockout mice do not present lysosomal accumulation of TTR in renal tubules when compared with control wild type littermates. Because TTR is a carrier of T4 and retinol (in the latter case by the formation of a complex with RBP), it is possible that the presented mechanism is of potential importance in the transepithelial transport of retinol or thyroxine or both. Because RBP is also a megalin ligand (9), TTR might be more important for the renal uptake of T4.
Thyroid hormones are synthesized in the thyroid gland and are important in regulating basal metabolism and in controlling cellular growth and differentiation (33). T4 represents the majority of the hormone synthesized and the major circulating form in the plasma. Triiodothyronine, the biologically active form of the hormone, derives mostly from T4 deiodination in the peripheral tissues including the kidney (15). Once secreted, more than 99% of the thyroid hormones in circulation are bound to plasma proteins. In human plasma, TTR is one of the three proteins responsible for the transport of T4, the main carrier being thyroxine-binding globulin; albumin is the third T4-binding protein and the one that presents the lowest affinity for the hormone (14). In rodent serum, TTR is the major carrier of T4. Interestingly, albumin is known to be taken up in the proximal tubules by two receptors: megalin and the co-localizing receptor, cubilin (34).
Plasma TTR derives mostly from the liver and transports about 15% of T4, which may be reabsorbed via megalin. However, in transthyretin null mice (35) it was shown that T4 and triiodothyronine tissue content is normal in the case of the kidney and that the amount of deiodinase mRNA, which is directly correlated with the enzymatic activity, remains unaltered in this tissue (36). However, the putative importance of TTR in the normal physiological uptake of T4 should not be disregarded, because it is possible that a redundant mechanism accounts for T4 uptake in TTR knockout mice. The thyroid hormone status of megalin knockouts should be addressed in the future for the possibility that these animals excrete T4 in the urine as a result of a lack of TTR uptake in the proximal tubules.
Several point mutations have been described in TTR (30), the most common being a Val for Met substitution at position 30 of the protein (30). Most of these mutations are related to the occurrence of familial amyloidotic polyneuropathy, which is an autosomal dominant disorder that is characterized by the deposition of amyloid fibrils in several tissues, particularly in the peripheral nervous system (31). Some of these TTR mutants were used to evaluate binding to megalin, and in accordance with the binding data, TTR structure seems to be important for the uptake by megalin.
It is interesting to note that TTR plasma levels are decreased in familial amyloidotic polyneuropathy V30M patients (37), despite an equal expression of the variant and normal TTR in the liver. These facts suggested that TTR metabolism could be involved in the amyloid formation process. Comparative clearance studies of TTR V30M and TTR T119M have been performed (38) and showed a slower clearance for TTR T119M and a faster one for TTR V30M. This led to the hypothesis that, at least in part, the different clearances could account for the differences in circulating plasma levels observed for each of the mutations. It was speculated that one of the factors that might be involved in the existence of differences in clearance would be the existence of cellular receptors for TTR with different affinities for the two mutant forms of the protein. This has been demonstrated here in the case of megalin.
TTR has also been described to interact with a variety of compounds;
the significance of these interactions is, in most cases, still
unexplained. These minor TTR ligands include noradrenaline oxidation
products (39), pterins (40), chicken lutein, hemin and hemoglobin (41),
polyhalogenated compounds (42), and retinoic acid (43). The
megalin-mediated TTR uptake in the proximal tubules may also be
important in the uptake of these TTR ligands. In conclusion, the
findings here presented show TTR as a novel megalin ligand with
potential importance in T4 transepithelial transport and reinforce the concept that megalin is a general endocytic receptor for
protein in the proximal tubule (23), with a multifaceted role in
retaining and capturing vital substances from the tubular fluid after
glomerular filtration.
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ACKNOWLEDGEMENTS |
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We thank Paul Moreira for the production of recombinant TTR.
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FOOTNOTES |
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* This work was supported by grants from PRAXIS XXI (2/2.1/BIA/459/94) from Portugal (to M. J. S.), the Novo Nordisk Foundation, the Danish Biotechnology Program, and the University of Aarhus (to S. K. M.), and the Sir Jules Thorn Charitable Fund (to A. G. W. N.).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.
c Recipient of a post-doctoral fellowship (PRAXIS XXI/BPD/22027/99) from Fundação para a Ciência e Tecnologia (Portugal).
j To whom correspondence should be addressed: Amyloid Unit, Instituto de Biologia Molecular e Celular, Rua do Campo Alegre 823, Porto 4150, Portugal. Tel.: 351-22-6074900; Fax: 351-22-6099157; E-mail: mjsaraiv@ibmc.up.pt.
Published, JBC Papers in Press, September 11, 2000, DOI 10.1074/jbc.M002886200
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ABBREVIATIONS |
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The abbreviations used are: RAP, receptor associated protein; RBP, retinol-binding protein; TTR, transthyretin; T4, thyroxine; PBS, phosphate-buffered saline; BN, Brown Norway; SPR, surface plasmon resonance.
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| 1. | Christensen, E. I., Nielsen, S., Moestrup, S. K., Borre, C., Maunsbach, A. B., de Heer, E., Ronco, P., Hammond, T. G., and Verroust, P. (1995) Eur. J. Cell Biol. 66, 349-364 |
| 2. | Zheng, G., Bachinsky, D. R., Stamenkovic, I., Strickland, D. K., Brown, D., Andres, G., and McCluskey, R. T. (1994) J. Histochem. Cytochem. 42, 531-542 |
| 3. | Hussain, M. M., Strickland, D. K., and Bakillah, A. (1999) Annu. Rev. Nutr. 19, 141-172 |
| 4. | Christensen, E. I., Gliemann, J., and Moestrup, S. K. (1992) J. Histochem. Cytochem. 40, 1481-1490 |
| 5. | Birn, H., Vorum, H., Verroust, P. J., Moestrup, S. K., and Christensen, E. I. (2000) J. Am. Soc. Nephrol. 11, 191-202 |
| 6. | Willnow, T. E. (1998) Biol. Chem. 379, 1025-1031 |
| 7. | Moestrup, S. K., Birn, H., Fischer, P. B., Petersen, C. M., Verroust, P. J., Sim, R. B., Christensen, E. I., and Nexo, E. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 8612-8617 |
| 8. | Nykjaer, A., Dragun, D., Walther, D., Vorum, H., Jacobsen, C., Herz, J., Melsen, F., Christensen, E. I., and Willnow, T. E. (1999) Cell 96, 507-515 |
| 9. | Christensen, E. I., Moskaug, J. O., Vorum, H., Jacobsen, C., Gundersen, T. E., Nykjaer, A., Blomhoff, R., Willnow, T. E., and Moestrup, S. K. (1999) J. Am. Soc. Nephrol. 10, 685-695 |
| 10. | Willnow, T. E., Hilpert, J., Armstrong, S. A., Rohlmann, A., Hammer, R. E., Burns, D. K., and Herz, J. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 8460-8464 |
| 11. | Leheste, J. R., Rolinski, B., Vorum, H., Hilpert, J., Nykjaer, A., Jacobsen, C., Aucouturier, P., Moskaug, J. O., Otto, A., Christensen, E. I., and Willnow, T. E. (1999) Am. J. Pathol. 155, 1361-1370 |
| 12. | Raz, A., Shiratori, T., and Goodman, D. S. (1970) J. Biol. Chem. 245, 1903-1912 |
| 13. | Green, M. H., and Green, J. B. (1994) in Vitamin A in Health and Disease (Blomhoff, R., ed) , pp. 119-133, Marcel Dekker, New York |
| 14. | Blake, C. C. F., and Swan, I. D. A. (1972) J. Mol. Biol. 61, 217-224 |
| 15. | Kohrle, J., Hesch, R. D., and Leonard, J. L. (1991) in The Thyroid (Braverman, L. E. , and Utiger, R. D., eds), 6th Ed. , pp. 144-189, Lippincott, Philadelphia |
| 16. | Makover, A., Soprano, D. R., Wyatt, M. L., and Goodman, D. S. (1989) J. Lipid Res. 30, 171-180 |
| 17. | Gray, H. D., Gray, E. S., and Horne, C. H. (1985) Virchows Arch. A Pathol. Anat. Histopathol. 406, 463-473 |
| 18. | Makover, A., Moriwaki, H., Ramakrishnan, R., Saraiva, M. J., Blaner, W. S., and Goodman, D. S. (1988) J. Biol. Chem. 263, 8598-8603 |
| 19. | Divino, C. M., and Schussler, G. C. (1990) J. Biol. Chem. 265, 1425-1429 |
| 20. | Almeida, M. R., Damas, A. M., Lans, M. C., Brower, A., and Saraiva, M. J. (1997) Endocrine 6, 309-315 |
| 21. | Herz, J., Goldstein, J. L., Strickland, D. K., Ho, Y. K., and Brown, M. S. (1991) J. Biol. Chem. 266, 21232-21238 |
| 22. | Moestrup, S. K., Nielsen, S., Andreasen, P., Jorgensen, K. E., Nykjaer, A., Roigaard, H., Gliemann, J., and Christensen, E. I. (1993) J. Biol. Chem. 268, 16564-16570 |
| 23. | Christensen, E. I., Birn, H., Verroust, P., and Moestrup, S. K. (1998) Int. Rev. Cytol. 180, 237-284 |
| 24. | Le Panse, S., Galceran, M., Pontillon, F., Lelongt, B., van de Putte, M., Ronco, P. M., and Verroust, P. J. (1995) Eur. J. Cell Biol. 67, 120-129 |
| 25. | Moestrup, S. K., Schousboe, I., Jacobsen, C., Leheste, J. R., Christensen, E. I., and Willnow, T. E. (1998) J. Clin. Invest. 102, 902-909 |
| 26. | Kato, M., Kato, K., Blaner, W. S., Chertow, B. S., and Goodman, D. S. (1985) Proc. Natl. Acad. Sci. U. S. A. 82, 2488-2492 |
| 27. | Wrong, O. M., Norden, A. G. W., and Feest, T. G. (1994) Q. J. Med. 87, 473-493 |
| 28. | Lloyd, S. E., Pearce, S. H. S., Fisher, S. E., Steimeyer, K., Schwappach, B., Scheinman, S. J., Harding, B., Bolino, A., Devoto, M., Goodyer, P., Rigden, S. P. A., Wrong, O., Jentsch, T. J., Craig, I. W., and Thakker, R. V. (1996) Nature 379, 445-446 |
| 29. | Moestrup, S. K., Kozyraki, R., Kristiansen, M., Kaysen, J. H., Rasmussen, H. H., Brault, D., Pontillon, F., Goda, F. O., Christensen, E. I., Hammond, T. G., and Verroust, P. J. (1998) J. Biol. Chem. 273, 5235-5242 |
| 30. | Saraiva, M. J. (1995) Hum. Mutat. 5, 191-196 |
| 31. | Andrade, C. (1952) Brain 75, 408-427 |
| 32. | Devuyst, O., Christie, P. T., Courtoy, P. J., Beauwens, R., and Thakker, R. V. (1999) Hum. Mol. Genet. 8, 247-257 |
| 33. | Stein, S. A., Adams, P. M., Shanklin, D. R., Mihailoff, G. A., and Palnitkar, M. B. (1991) in Advances in Perinatal Thyroidology (Bercu, B. B. , and Shulman, D. I., eds) , pp. 47-105, Plenum Press, New York |
| 34. | Birn, H., Fyfe, J., Jacobsen, C., Mounier, F., Verroust, P. J., Ørskov, H., Willnow, T. E., Moestrup, S. K., and Christensen, E. I. (2000) J. Clin. Invest. 105, 1353-1361 |
| 35. | Episkopou, V., Maeda, S., Nishiguchi, S., Shimada, K., Gaitanaris, G. A., Gottesman, M. E., and Robertson, E. J. (1993) Proc. Natl. Acad. Sci. U. S. A. 90, 2375-2379 |
| 36. | Palha, J. A., Hays, M. T., Morreale de Escobar, G., Episkopou, V., Gottesman, M. E., and Saraiva, M. J. (1997) Am. J. Physiol. 272, E485-E493 |
| 37. | Saraiva, M. J. M, Costa, P. P., and Goodman, D. S. (1985) J. Clin. Invest. 76, 2171-2177 |
| 38. | Alves, I., Hays, M. T., and Saraiva, M. J. (1997) Eur. J. Biochem. 249, 662-668 |
| 39. | Boomsma, F., Veld, A. J. M., and Schalekamp, A. D. H. (1991) J. Pharmacol. Exp. Ther. 259, 551-557 |
| 40. | Ernstrom, U., Petterson, T., and Jornvall, H. (1995) FEBS Lett. 360, 177-182 |
| 41. | Martone, R., and Herbert, J. (1993) J. Rheumatol. 20, 176 |
| 42. | Cheek, A. O., Kow, K., Chen, J., and McLachlan, J. A. (1999) Environ. Health Perspect. 107, 273-278 |
| 43. | Smith, T. J., Davis, F. B., Deziel, M. R., Davis, P. J., Ramsden, D. B., and Schoenl, M. (1994) Biochim. Biophys. Acta 1199, 76-80 |
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