10. Regulation of certain enzymes involved in synthesis of simple lipids, complex lipids and ketone bodies

Regulation of lipid synthesis?

lipin, also known as phosphatidic acid phosphatase is active when dephosphorylated.

FFA activates the dephosphorylation of lipin

regulation of ketone body synthesis?

ketone bodies are only produced when the glucose levels are low

this cause a shunt of OAA from the TCA cycle, towards gluconeogenesis

the acetyl-CoA formed from β-oxidation of FA will no longer be able to combine W/ OAA to form citrate rather its converted into ketone bodies

HMG-CoA synthase?

the accumulation of acetyl-coA in the mitochondria will spontaneously acetylate HMG-CoA synthase

however, a protein called SIRT3 can deacetylate, and active HMG-CoA synthase

FOXA2 is a transcription factor which is activated by signalling from glucagon, and inactivated by insulin signalling. FOXA2 is a TF for enzymes involved in β-oxidation and ketogenesis

glucagon is also involved in increasing the availability of FA, thus acetyl-CoA via hormone-sensitive lipase

what happens during starvation in case of lipin ?

In case of starvation, mTOR is activated and will phosphorylate lipin. 14-3-3, a chaperone which arrested lipin and inactivate the lipin