Adipose Differentiation Related Protein (ADRP) Expressed in Transfected COS-7 Cells Selectively Stimulates Long Chain Fatty Acid Uptake*
- From the Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland 21201-1180 and the Program of Oncology, Marlene and Stewart Greenebaum Cancer Center of the University of Maryland, Baltimore, Maryland 21201-1180
Abstract
Adipose differentiation related protein (ADRP) is a 50-kDa novel protein cloned from a mouse 1246 adipocyte cDNA library, rapidly induced during adipocyte differentiation. We have examined ADRP function, and we show here that ADRP facilitates fatty acid uptake in COS cells transfected with ADRP cDNA. We demonstrate that uptake of long chain fatty acids was significantly stimulated in a time-dependent fashion in ADRP-expressing COS-7 cells compared with empty vector-transfected control cells. Oleic acid uptake velocity increased significantly in a dose-dependent manner in ADRP-expressing COS-7 cells compared with control cells. The transport K m was 0.051 μm, andV max was 57.97 pmol/105 cells/min in ADRP-expressing cells, and K m was 0.093 μm and V max was 20.13 pmol/105 cells/min in control cells. The oleate uptake measured at 4 °C was only 10% that at 37 °C. ADRP also stimulated uptake of palmitate and arachidonate but had no effect on uptake of medium chain fatty acid such as octanoic acid and glucose. These data suggest that ADRP specifically enhances uptake of long chain fatty acids by increasing the initial rate of uptake and provide novel information about ADRP function as a saturable transport component for long chain fatty acids.
Footnotes
-
↵* This work was supported in part by Grants RO1 DK 51463 from the National Institutes of Health and Grant 194174 from the Juvenile Diabetes Foundation International.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.
-
↵‡ Current address: Dept. of Central Nervous System and Cardiovascular Research, Schering-Plough Research Institute, 2015 Galloping Hill Rd., Kenilworth, NJ 07033.
-
↵§ To whom correspondence should be addressed: Dept. of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 N. Pine St., Baltimore, MD 21201-1180. Tel.: 410-706-6639; Fax: 410-706-0346; E-mail: gserrero{at}pharmacy.ab.umd.edu.
-
↵2 B. Condon and G. Serrero, manuscript in preparation.
-
↵3 J. Gao, H. Ye, and G. Serrero, submitted for publication.
- Abbreviations:
- FA
-
fatty acids
- ADRP
-
adipose differentiation related protein
- BSA
-
fatty acid-free bovine serum albumin
- DME-F12
-
1 to 1 mixture of Dulbecco’s modified Eagle’s and Ham’s F12 media
- FITC
-
fluorescein isothiocyanate
- GFP
-
green fluorescent protein
- KRP
-
Krebs-Ringer phosphate buffer
- PBS
-
phosphate-buffered saline
- PAGE
-
polyacrylamide gel electrophoresis
- FBS
-
fetal bovine serum
- FAT
-
fatty acid translocase
- FATP
-
fatty acid transport protein
- FABPpm
-
plasma membrane fatty acid-binding protein
-
- Received November 16, 1998.
- Revision received February 22, 1999.
- The American Society for Biochemistry and Molecular Biology, Inc.
