Phosphatidylcholine:ceramide cholinephosphotransferase 2 (EC 2.7.8.27) (Sphingomyelin synthase 2)
1_MDIIE 6_ TAKLE 11_ EHLEN 16_ QPSDP 21_ TNTYA 26_ RPAEP 31_ VEEEN 36_ KNGNG 41_ KPKSL 46_ SSGLR 51_ KGTKK 56_ YPDYI 61_ QIAMP 66_ TESRN 71_ KFPLE 76_ WWKTG 81_ IAFIY 86_ AVFNL 91_ VLTTV 96_ MITVV 101_ HERVP 106_ PKELS 111_ PPLPD 116_ KFFDY 121_ IDRVK 126_ WAFSV 131_ SEING 136_ IILVG 141_ LWITQ 146_ WLFLR 151_ YKSIV 156_ GRRFC 161_ FIIGT 166_ LYLYR 171_ CITMY 176_ VTTLP 181_ VPGMH 186_ FQCAP 191_ KLNGD 196_ SQAKV 201_ QRILR 206_ LISGG 211_ GLSIT 216_ GSHIL 221_ CGDFL 226_ FSGHT 231_ VTLTL 236_ TYLFI 241_ KEYSP 246_ RHFWW 251_ YHLIC 256_ WLLSA 261_ AGIIC 266_ ILVAH 271_ EHYTI 276_ DVIIA 281_ YYITT 286_ RLFWW 291_ YHSMA 296_ NEKNL 301_ KVSSQ 306_ TNFLS 311_ RAWWF 316_ PIFYF 321_ FEKNV 326_ QGSIP 331_ CCFSW 336_ PLSWP 341_ PGCFK 346_ SSCKK 351_ YSRVQ 356_KIGED
1: Sphingomyelin synthase that primarily contributes to sphingomyelin synthesis and homeostasis at the plasma membrane. Catalyzes the reversible transfer of phosphocholine moiety in sphingomyelin biosynthesis: in the forward reaction transfers phosphocholine head group of phosphatidylcholine (PC) on to ceramide (CER) to form ceramide phosphocholine (sphingomyelin, SM) and diacylglycerol (DAG) as by-product, and in the reverse reaction transfers phosphocholine from SM to DAG to form PC and CER (PubMed:14685263, PubMed:17449912, PubMed:17982138, PubMed:18370930, PubMed:38388831). The direction of the reaction appears to depend on the levels of CER and DAG in the plasma membrane (PubMed:14685263, PubMed:17449912, PubMed:17982138, PubMed:18370930). Does not use free phosphorylcholine or CDP-choline as donors (PubMed:14685263). Can also transfer phosphoethanolamine head group of phosphatidylethanolamine (PE) on to ceramide (CER) to form ceramide phosphoethanolamine (CPE) (PubMed:19454763). Regulates receptor-mediated signal transduction via mitogenic DAG and proapoptotic CER, as well as via SM, a structural component of membrane rafts that serve as platforms for signal transduction and protein sorting (PubMed:17449912, PubMed:17982138). To a lesser extent, plays a role in secretory transport via regulation of DAG pool at the Golgi apparatus and its downstream effects on PRKD1 (PubMed:18370930, PubMed:21980337). Required for normal bone matrix mineralization (PubMed:30779713)