Effect of fatty acid translocase on oleate uptake in cultured fibroblasts

Purpose: The mechanism(s) for specific long chain fatty acid (LCFA) permeation of the plasma membrane is unclear. Five distinct plasma membrane proteins have been proposed as LCFA transporters including the CD36 homologous. Fatty Acid Translocase (FAT). In this study we utilized the fibroblast-like L-929 cell line to investigate the role of FAT in cellular oleate uptake. Methods: L-929 cells were transiently transfected with the cDNA for FAT utilizing the vector CMVneo. Northern blot analysis revealed a high level of expression of FAT mRNA in transfected fibroblasts with no expression identified in either wild-type L-929 cells or control cells transiently transfected with vector alone. Results: Time course transport experiments demonstrated an increase in oleate uptake in cells transfected with the FAT cDNA compared to cells transfected with vector alone. Non-linear regression analysis was utilized to determine the initial rate of oleate uptake in 3 separate time course experiments. The FAT transfected cells demonstrated a 2.7 fold increase in the initial oleate uptake rate compared to control cells (4.58 ±0.43 vs 1.63 ± 0.90 nmol/mg proteinAnin, p < 0.05). Conclusion: These findings support a role for the Fatty Acid Translocase membrane protein in the cellular uptake of long chain fatty acids.