Sphingomyelin synthase-related protein 1 (SMSr) (EC 2.7.8.-) (Ceramide phosphoethanolamine synthase) (CPE synthase) (Sterile alpha motif domain-containing protein 8) (SAM domain-containing protein 8)
1_MAGPN 6_ QLCIR 11_ RWTTK 16_ HVAVW 21_ LKDEG 26_ FFEYV 31_ DILCN 36_ KHRLD 41_ GITLL 46_ TLTEY 51_ DLRSP 56_ PLEIK 61_ VLGDI 66_ KRLML 71_ SVRKL 76_ QKIHI 81_ DVLEE 86_ MGYNS 91_ DSPMG 96_ SMTPF 101_ ISALQ 106_ STDWL 111_ CNGEL 116_ SHDCD 121_ GPITD 126_ LNSDQ 131_ YQYMN 136_ GKNKH 141_ SVRRL 146_ DPEYW 151_ KTILS 156_ CIYVF 161_ IVFGF 166_ TSFIM 171_ VIVHE 176_ RVPDM 181_ QTYPP 186_ LPDIF 191_ LDSVP 196_ RIPWA 201_ FAMTE 206_ VCGMI 211_ LCYIW 216_ LLVLL 221_ LHKHR 226_ SILLR 231_ RLCSL 236_ MGTVF 241_ LLRCF 246_ TMFVT 251_ SLSVP 256_ GQHLQ 261_ CTGKI 266_ YGSVW 271_ EKLHR 276_ AFAIW 281_ SGFGM 286_ TLTGV 291_ HTCGD 296_ YMFSG 301_ HTVVL 306_ TMLNF 311_ FVTEY 316_ TPRSW 321_ NFLHT 326_ LSWVL 331_ NLFGI 336_ FFILA 341_ AHEHY 346_ SIDVF 351_ IAFYI 356_ TTRLF 361_ LYYHT 366_ LANTR 371_ AYQQS 376_ RRARI 381_ WFPMF 386_ SFFEC 391_ NVNGT 396_ VPNEY 401_ CWPFS 406_KPAIM
1: Synthesizes sphingolipids through transfer of a phosphatidyl head group from a glycerophospholipid on to the primary hydroxyl of a ceramide in the lumen of the endoplasmic reticulum (PubMed:19506037, PubMed:38388831). Catalyzes the synthesis of ceramide phosphoethanolamines (CPEs) (such as N-acylsphing-4-enine 1-phosphoethanolamine) by transferring phosphoethanolamine head group, which is smaller and more hydrophilic than the phosphocholine (PC) headgroup transferred in the canonical sphingomyelin synthesis (SMS) reaction by SMS1 or SMS2, from a phosphatidylethanolamine (1,2-diacyl-sn-glycero-3-phosphoethanolamine, PE) to a ceramide (such as N-acylsphing-4-enine) (PubMed:19506037, PubMed:38388831). The larger PC prevents an efficient fit in the enzyme's catalytic pocket, leading to little or no SMS activity (PubMed:19506037, PubMed:38388831). In vitro, in the absence of ceramide, it has PLC activity with preference for phosphatidylinositol and phosphatidic acid, but also hydrolyzes phosphatidylethanolamine (PubMed:33621517, PubMed:38388831)