The protein encoded by this gene is predicted to be a five-pass transmembrane protein. This gene may be predominately expressed in brain. [provided by RefSeq, Jul 2008],
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Function:
Catalytic activity:A ceramide + a phosphatidylcholine = a sphingomyelin + a 1,2-diacyl-sn-glycerol.,enzyme regulation:Inhibited by bacterial PC-phospholipase C inhibitor D609.,Function:Bidirectional lipid cholinephosphotransferase capable of converting phosphatidylcholine (PC) and ceramide to sphingomyelin (SM) and diacylglycerol (DAG) and vice versa. Direction is dependent on the relative concentrations of DAG and ceramide as phosphocholine acceptors. Directly and 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 SM synthase. Suppresses BAX-mediated apoptosis and also prevents cell death in response to stimuli such as hydrogen peroxide, osmotic stress, elevated temperature and exogenously supplied sphingolipids. May protect against cell death by reversing the stress-inducible increase in levels of proapoptotic ceramide. Required for cell growth.,miscellaneous:Overexpression of the human protein in mouse causes increased non-HDL-sphingomyelin and non-HDL cholesterol levels, decreased HDL-sphingomyelin and HDL-cholesterol levels and increases lipoprotein atherogenic potential.,sequence Caution:Unusual initiator. The initiator methionine is coded by a non-canonical CTG leucine codon.,similarity:Belongs to the sphingomyelin synthase family.,similarity:Contains 1 SAM (sterile alpha motif) domain.,tissue specificity:Brain, heart, kidney, liver, muscle and stomach.,
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Cellular Localization:
Golgi apparatus membrane ; Multi-pass membrane protein .