Fatty acids are incorporated into membranes and signaling molecules and have roles in energy storage and metabolism. These essential functions require activation of the fatty acid by acyl-coenzyme A (CoA) synthetases, such as ACSF2, which form an activating thioester linkage between the fatty acid and CoA.The deduced 615-amino acid protein contains all 5 motifs characteristic of acyl-CoA synthetases. Phylogenetic analysis revealed that ACSF2 belongs to a small group of acyl-CoA synthetases that differ significantly from all other clades of acyl-CoA synthetases and from each other. FLJ20920 contains a PPARG-recognition element in its promoter sequence. Transfection of antisense FLJ20920 into preadipocytes resulted in decreased triglyceride accumulation and reduced expression of GLUT4 (SLC2A4) and HSL (LIPE) mRNA.