Publications

• FATP2 is a hepatic fatty acid transporter and peroxisomal very long-chain acyl-CoA synthetase.

  Falcon A., Doege H., Fluitt A., Tsang B., Watson N., Kay M.A., Stahl A.

  Fatty acid transport protein (FATP)2, a member of the FATP family of fatty acid uptake mediators, has independently been identified as a hepatic peroxisomal very long-chain acyl-CoA synthetase (VLACS). Here we address whether FATP2 is 1) a peroxisomal enzyme, 2) a plasma membrane-associated long-c ... >> More

  Fatty acid transport protein (FATP)2, a member of the FATP family of fatty acid uptake mediators, has independently been identified as a hepatic peroxisomal very long-chain acyl-CoA synthetase (VLACS). Here we address whether FATP2 is 1) a peroxisomal enzyme, 2) a plasma membrane-associated long-chain fatty acid (LCFA) transporter, or 3) a multifunctional protein. We found that, in mouse livers, only a minor fraction of FATP2 localizes to peroxisomes, where it contributes to approximately half of the peroxisomal VLACS activity. However, total hepatic (V)LACS activity was not significantly affected by loss of FATP2, while LCFA uptake was reduced by 40%, indicating a more prominent role in hepatic LCFA uptake. This suggests FATP2 as a potential target for a therapeutic intervention of hepatosteatosis. Adeno-associated virus 8-based short hairpin RNA expression vectors were used to achieve liver-specific FATP2 knockdown, which significantly reduced hepatosteatosis in the face of continued high-fat feeding, concomitant with improvements in liver physiology, fasting glucose, and insulin levels. Based on our findings, we propose a model in which FATP2 is a multifunctional protein that shows subcellular localization-dependent activity and is a major contributor to peroxisomal (V)LACS activity and hepatic fatty acid uptake, suggesting FATP2 as a potential novel target for the treatment of nonalcoholic fatty liver disease. << Less

  Am. J. Physiol. 299:E384-393(2010) [PubMed] [EuropePMC]

• Comparative biochemical studies of the murine fatty acid transport proteins (FATP) expressed in yeast.

  DiRusso C.C., Li H., Darwis D., Watkins P.A., Berger J., Black P.N.

  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 ve ... >> More

  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. << Less

  J. Biol. Chem. 280:16829-16837(2005) [PubMed] [EuropePMC]

  This publication is cited by 5 other entries.

• Functional domains of the fatty acid transport proteins: studies using protein chimeras.

  DiRusso C.C., Darwis D., Obermeyer T., Black P.N.

  Fatty acid transport proteins (FATP) function in fatty acid trafficking pathways, several of which have been shown to participate in the transport of exogenous fatty acids into the cell. Members of this protein family also function as acyl CoA synthetases with specificity towards very long chain f ... >> More

  Fatty acid transport proteins (FATP) function in fatty acid trafficking pathways, several of which have been shown to participate in the transport of exogenous fatty acids into the cell. Members of this protein family also function as acyl CoA synthetases with specificity towards very long chain fatty acids or bile acids. These proteins have two identifying sequence motifs: The ATP/AMP motif, an approximately 100 amino acid segment required for ATP binding and common to members of the adenylate-forming super family of proteins, and the FATP/VLACS motif that consists of approximately 50 amino acid residues and is restricted to members of the FATP family. This latter motif has been implicated in fatty acid transport in the yeast FATP orthologue Fat1p. In the present studies using a yeast strain containing deletions in FAT1 (encoding Fat1p) and FAA1 (encoding the major acyl CoA synthetase (Acsl) Faa1p) as an experimental platform, the phenotypic and functional properties of specific murine FATP1-FATP4 and FATP6-FATP4 protein chimeras were evaluated in order to define elements within these proteins that further distinguish the fatty acid transport and activation functions. As expected from previous work FATP1 and FATP4 were functional in the fatty acid transport pathway, while and FATP6 was not. All three isoforms were able to activate the very long chain fatty acids arachidonate (C(20:4)) and lignocerate (C(24:0)), but with distinguishing activities between saturated and highly unsaturated ligands. A 73 amino acid segment common to FATP1 and FATP4 and between the ATP/AMP and FATP/VLACS motifs was identified by studying the chimeras, which is hypothesized to contribute to the transport function. << Less

  Biochim Biophys Acta 1781:135-143(2008) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Human fatty acid transport protein 2a/very long chain acyl-CoA synthetase 1 (FATP2a/Acsvl1) has a preference in mediating the channeling of exogenous n-3 fatty acids into phosphatidylinositol.

  Melton E.M., Cerny R.L., Watkins P.A., DiRusso C.C., Black P.N.

  The trafficking of fatty acids across the membrane and into downstream metabolic pathways requires their activation to CoA thioesters. Members of the fatty acid transport protein/very long chain acyl-CoA synthetase (FATP/Acsvl) family are emerging as key players in the trafficking of exogenous fat ... >> More

  The trafficking of fatty acids across the membrane and into downstream metabolic pathways requires their activation to CoA thioesters. Members of the fatty acid transport protein/very long chain acyl-CoA synthetase (FATP/Acsvl) family are emerging as key players in the trafficking of exogenous fatty acids into the cell and in intracellular fatty acid homeostasis. We have expressed two naturally occurring splice variants of human FATP2 (Acsvl1) in yeast and 293T-REx cells and addressed their roles in fatty acid transport, activation, and intracellular trafficking. Although both forms (FATP2a (M(r) 70,000) and FATP2b (M(r) 65,000 and lacking exon3, which encodes part of the ATP binding site)) were functional in fatty acid import, only FATP2a had acyl-CoA synthetase activity, with an apparent preference toward very long chain fatty acids. To further address the roles of FATP2a or FATP2b in fatty acid uptake and activation, LC-MS/MS was used to separate and quantify different acyl-CoA species (C14-C24) and to monitor the trafficking of different classes of exogenous fatty acids into intracellular acyl-CoA pools in 293T-REx cells expressing either isoform. The use of stable isotopically labeled fatty acids demonstrated FATP2a is involved in the uptake and activation of exogenous fatty acids, with a preference toward n-3 fatty acids (C18:3 and C22:6). Using the same cells expressing FATP2a or FATP2b, electrospray ionization/MS was used to follow the trafficking of stable isotopically labeled n-3 fatty acids into phosphatidylcholine and phosphatidylinositol. The expression of FATP2a resulted in the trafficking of C18:3-CoA and C22:6-CoA into both phosphatidylcholine and phosphatidylinositol but with a distinct preference for phosphatidylinositol. Collectively these data demonstrate FATP2a functions in fatty acid transport and activation and provides specificity toward n-3 fatty acids in which the corresponding n-3 acyl-CoAs are preferentially trafficked into acyl-CoA pools destined for phosphatidylinositol incorporation. << Less

  J. Biol. Chem. 286:30670-30679(2011) [PubMed] [EuropePMC]

  This publication is cited by 4 other entries.