Comparative studies of human fatty acid transport proteins 1, 4 and 6 in the vectorial acylation of exogenous long chain fatty acids

Abstract

The fatty acid transport protein (FATP) family consists of six members that are involved in the transport of exogenous long chain fatty acids (LCFAs) and the activation of very long chain fatty acids. Genetic and biochemical studies support the idea that several of the FATPs function in transport with a long chain acyl CoA synthetase by a process named as vectorial acylation. Two lines of experiments are being completed to define the role of selected FATP isoforms in vectorial acylation. In the first, we have expressed FATP1, FATP4 and FATP6 in a yeast strain devoid of both transport and activation activity. Our initial studies demonstrate FATP1 and 6 fail to function in fatty acid transport; FATP4 confers very low levels of it. Additional studies are evaluating complementation patterns relying on exogenous fatty acid transport and defining acyl CoA synthetase profiles using different fatty acid substrates. Second, we have cloned FATP1, 4 and 6 into pcDNA4/TO/myc‐His‐A and a tetracycline‐inducible promoter drives their regulated expression when transfected into T‐Rex 293 cells. We have generated stable lines expressing FATP1, 4 and 6 and the kinetic parameters of fatty acid transport are being determined using a live cell assay and the fluorescent fatty acid analog C1‐BODIPY‐C12. Additional studies are addressing localization of each of these proteins by immunofluorescence. Supported by a grant from the NIH (GM56850).