Submitted on June 12, 2006
Revised on November 10, 2006
Accepted on November 30, 2006
Involvement of the C-terminal cytoplasmic domain in the plasma membrane localization of FAT/CD36 and its ability to mediate long-chain fatty acid uptake
Nicholas S. Eyre, Leslie G. Cleland, Narendra N. Tandon, and Graham Mayrhofer
School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA 5005
Corresponding Author: graham.mayrhofer{at}adelaide.edu.au
This study investigates the role of the cytoplasmic carboxy-terminus of FAT/CD36 in localization of the molecule to the plasma membrane, its insertion into lipid rafts and its ability to enhance long-chain fatty acid (LCFA) uptake in transfected H4IIE rat hepatoma cells. In these cells, wild-type FAT/CD36 is localized to both lipid raft and non-raft domains of the plasma membrane. Interestingly, a FAT/CD36 truncation mutant lacking the final 10 amino acids of the cytoplasmic carboxy-terminus was retained within the cell in detergent-resistant membranes and, unlike wild-type FAT/CD36, it did not enhance oleate uptake. Furthermore, expression of FAT/CD36 in these cells increased incorporation of oleate into diacylglycerol; a property that was not shared by truncated FAT/CD36. To examine whether the C-terminus itself has an intrinsic ability to dictate plasma membrane localization of FAT/CD36, this region was fused in-frame to EGFP. This domain was sufficient to attach EGFP to cellular membranes, suggesting an involvement in the intracellular traffic of the molecule. We conclude that the C-terminus of FAT/CD36 is required for localization of the receptor to the cell surface and its ability to enhance cellular oleate uptake.