Characterization of the Biochemical Activities Associated with Splice Variants of Human FATP2

Abstract

One mechanism governing the transport of exogenous fatty acids (FA) is vectorial acylation whereby the imported FA is converted into acyl CoA upon transport as a consequence of the activities of the fatty acid transport proteins (FATP) and long chain acyl CoA synthetases (Acsl). Splice variants of human FATP2 have been identified that differ in the ATP binding region. FATP2a contains the entire ATP/AMP motif, while FATP2b lacks exon 3 resulting in a protein lacking critical residues within the ATP/AMP motif. Previously we have shown both forms are proficient in FA transport, but only FATP2a functions in very long chain FA activation. These findings demonstrate that these naturally occurring splice variants of FATP2 have distinct and separable biochemical activities. In order to investigate these splice variants further, both were cloned into pcDNA4/TO/myc‐His‐A allowing tetracycline regulated expression of the target protein containing a polyhistidine and c‐myc epitope tag. 293 T‐REx cell lines stably expressing either FATP2a or FATP2b have been generated. Current experimental studies are [1] defining the intracellular localization of both FATP2a and FATP2b, [2] correlating those observations with changes in FA transport and activation activities and [3] addressing the roles of both variants in the trafficking of exogenous FA into lipid metabolic pools. Supported by NIH grant GM56850.