Fig. 6.

Increase in BS levels due to the accumulation of β-hydroxy acyl-CoAs, which are intermediates in the FA elongation cycle. A: The FA elongation cycle localized in the ER produces acyl-CoAs having ≥C18 chain lengths. In each cycle, the chain length of the substrate acyl-CoA is elongated by two carbon chains through a four-step reaction. The enzymes involved in each reaction step and intermediates are depicted. β-Hydroxy acyl-CoA dehydratases HACD1 and HACD2 convert β-hydroxy acyl-CoAs to trans-2-enoyl-CoAs. B: Lipids were extracted from control and HACD1 HACD2 DKO HAP1 cells, and C18:0 BS was quantified by LC/MS/MS. Values represent means ± SDs (n = 3; **P < 0.01; two-tailed Student’s t-test).