The fatty acid transport protein (FATP1) is a very long chain acyl-CoA synthetase.
The primary sequence of the murine fatty acid transport protein (FATP1) is very similar to the multigene family of very long chain (C20-C26) acyl-CoA synthetases. To determine if FATP1 is a long chain acyl coenzyme A synthetase, FATP1-Myc/His fusion protein was expressed in COS1 cells, and its enzymatic activity was analyzed. In addition, mutations were generated in two domains conserved in acyl-CoA synthetases: a 6- amino acid substitution into the putative active site (amino acids 249-254) generating mutant M1 and a 59-amino acid deletion into a conserved C-terminal domain (amino acids 464-523) generating mutant M2. Immunolocalization revealed that the FATP1-Myc/His forms were distributed between the COS1 cell plasma membrane and intracellular membranes. COS1 cells expressing wild type FATP1-Myc/His exhibited a 3-fold increase in the ratio of lignoceroyl-CoA synthetase activity (C24:0) to palmitoyl-CoA synthetase activity (C16:0), characteristic of very long chain acyl-CoA synthetases, whereas both mutant M1 and M2 were catalytically inactive. Detergent-solubilized FATP1-Myc/His was partially purified using nickel-based affinity chromatography and demonstrated a 10-fold increase in very long chain acyl-CoA specific activity (C24:0/C16:0). These results indicate that FATP1 is a very long chain acyl-CoA synthetase and suggest that a potential mechanism for facilitating mammalian fatty acid uptake is via esterification coupled influx.
Coe
N R
NR
Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, St. Paul, Minnesota 55108, USA.
Smith
A J
AJ
Frohnert
B I
BI
Watkins
P A
PA
Bernlohr
D A
DA
D000818:Animals; D019556:COS Cells; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D003066:Coenzyme A Ligases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D050612:Fatty Acid Transport Proteins; D005227:Fatty Acids / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D026901:Membrane Transport Proteins; D017421:Sequence Analysis; D014162:Transfection
D002352:Carrier Proteins; D050612:Fatty Acid Transport Proteins; D005227:Fatty Acids; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D003066:Coenzyme A Ligases