phosphatidylcholine:ceramide cholinephosphotransferase 1; medulla oblongata-derived protein; protein Mob; sphingomyelin synthase 1; transmembrane protein 23 (SGMS1, MOB, SMS1, TMEM23)

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Function

bidirectional lipid cholinephosphotransferase capable of converting phosphatidylcholine & ceramide to sphingomyelin & diacylglycerol & vice versa
direction is dependent on the relative concentrations of diacylglycerol & ceramide as phosphocholine acceptors
directly & specifically recognizes the choline head group on the substrate
also requires two fatty chains on the choline-P donor molecule in order to be recognized efficiently as a substrate
does not function strictly as a sphingomyelin synthase
suppresses BAX-mediated apoptosis
prevents cell death in response to stimuli such as hydrogen peroxide, osmotic stress, elevated temperature & exogenously supplied sphingolipids
may protect against cell death by reversing the stress-inducible increase in levels of proapoptotic ceramide
required for cell growth

Inhibition:

brain, heart, kidney, liver, muscle and stomach

overexpression of the human protein in mouse causes increased non-HDL-sphingomyelin & non-HDL cholesterol levels, decreased HDL-sphingomyelin & HDL-cholesterol levels and increases lipoprotein atherogenic potential