title: Comparative biochemical studies of the murine fatty acid transport proteins (FATP) expressed in yeast.
abstract: The fatty acid transport protein (FATP) family is a group of proteins that are predicted to be components of specific fatty acid trafficking pathways. In mammalian systems, six different isoforms have been identified, which function in the import of exogenous fatty acids or in the activation of very long-chain fatty acids. This has led to controversy as to whether these proteins function as membrane-bound fatty acid transporters or as acyl-CoA synthetases, which activate long-chain fatty acids concomitant with transport. The yeast FATP orthologue, Fat1p, is a dual functional protein and is required for both the import of long-chain fatty acids and the activation of very long-chain fatty acids; these activities intrinsic to Fat1p are separable functions. To more precisely define the roles of the different mammalian isoforms in fatty acid trafficking, the six murine proteins (mmFATP1-6) were expressed and characterized in a genetically defined yeast strain, which cannot transport long-chain fatty acids and has reduced long-chain acyl-CoA synthetase activity (fat1Delta faa1Delta). Each isoform was evaluated for fatty acid transport, fatty acid activation (using C18:1, C20:4, and C24:0 as substrates), and accumulation of very long-chain fatty acids. Murine FATP1, -2, and -4 complemented the defects in fatty acid transport and very long-chain fatty acid activation associated with a deletion of the yeast FAT1 gene; mmFATP3, -5, and -6 did not complement the transport function even though each was localized to the yeast plasma membrane. Both mmFATP3 and -6 activated C20:4 and C20:4, while the expression of mmFATP5 did not substantially increase acyl-CoA synthetases activities using the substrates tested. These data support the conclusion that the different mmFATP isoforms play unique roles in fatty acid trafficking, including the transport of exogenous long-chain fatty acids.
authors.affiliation: Ordway Research Institute, Center for Metabolic Disease, Albany, New York 12208, USA.
authors.forename: Concetta C
authors.initials: CC
authors.lastname: DiRusso
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Dina
authors.initials: D
authors.lastname: Darwis
authors.forename: Paul A
authors.initials: PA
authors.lastname: Watkins
authors.forename: Johannas
authors.initials: J
authors.lastname: Berger
authors.forename: Paul N
authors.initials: PN
authors.lastname: Black
mesh_terms: D000818:Animals; D001692:Biological Transport; D001896:Boron Compounds / Q000494:pharmacology; D015820:Cadherins / Q000737:chemistry; D004247:DNA / Q000378:metabolism; D050612:Fatty Acid Transport Proteins; D005227:Fatty Acids / Q000378:metabolism; D005816:Genetic Complementation Test; D026901:Membrane Transport Proteins / Q000737:chemistry*; D051379:Mice; D010170:Palmitoyl-CoA Hydrolase / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D016133:Polymerase Chain Reaction; D020033:Protein Isoforms; D012441:Saccharomyces cerevisiae / Q000378:metabolism
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D015820:Cadherins; D050612:Fatty Acid Transport Proteins; D005227:Fatty Acids; D026901:Membrane Transport Proteins; D020033:Protein Isoforms; C493569:Slc27a1 protein, mouse; C493572:Slc27a4 protein, mouse; C502406:fat1 protein, mouse; D004247:DNA; D010170:Palmitoyl-CoA Hydrolase