Complement C1s subcomponent (EC 3.4.21.42) (C1 esterase) (Complement component 1 subcomponent s) [Cleaved into: Complement C1s subcomponent heavy chain; Complement C1s subcomponent light chain]
1_MWCIV 6_ LFSLL 11_ AWVYA 16_ EPTMY 21_ GEILS 26_ PNYPQ 31_ AYPSE 36_ VEKSW 41_ DIEVP 46_ EGYGI 51_ HLYFT 56_ HLDIE 61_ LSENC 66_ AYDSV 71_ QIISG 76_ DTEEG 81_ RLCGQ 86_ RSSNN 91_ PHSPI 96_ VEEFQ 101_ VPYNK 106_ LQVIF 111_ KSDFS 116_ NEERF 121_ TGFAA 126_ YYVAT 131_ DINEC 136_ TDFVD 141_ VPCSH 146_ FCNNF 151_ IGGYF 156_ CSCPP 161_ EYFLH 166_ DDMKN 171_ CGVNC 176_ SGDVF 181_ TALIG 186_ EIASP 191_ NYPKP 196_ YPENS 201_ RCEYQ 206_ IRLEK 211_ GFQVV 216_ VTLRR 221_ EDFDV 226_ EAADS 231_ AGNCL 236_ DSLVF 241_ VAGDR 246_ QFGPY 251_ CGHGF 256_ PGPLN 261_ IETKS 266_ NALDI 271_ IFQTD 276_ LTGQK 281_ KGWKL 286_ RYHGD 291_ PMPCP 296_ KEDTP 301_ NSVWE 306_ PAKAK 311_ YVFRD 316_ VVQIT 321_ CLDGF 326_ EVVEG 331_ RVGAT 336_ SFYST 341_ CQSNG 346_ KWSNS 351_ KLKCQ 356_ PVDCG 361_ IPESI 366_ ENGKV 371_ EDPES 376_ TLFGS 381_ VIRYT 386_ CEEPY 391_ YYMEN 396_ GGGGE 401_ YHCAG 406_ NGSWV 411_ NEVLG 416_ PELPK 421_ CVPVC 426_ GVPRE 431_ PFEEK 436_ QRIIG 441_ GSDAD 446_ IKNFP 451_ WQVFF 456_ DNPWA 461_ GGALI 466_ NEYWV 471_ LTAAH 476_ VVEGN 481_ REPTM 486_ YVGST 491_ SVQTS 496_ RLAKS 501_ KMLTP 506_ EHVFI 511_ HPGWK 516_ LLEVP 521_ EGRTN 526_ FDNDI 531_ ALVRL 536_ KDPVK 541_ MGPTV 546_ SPICL 551_ PGTSS 556_ DYNLM 561_ DGDLG 566_ LISGW 571_ GRTEK 576_ RDRAV 581_ RLKAA 586_ RLPVA 591_ PLRKC 596_ KEVKV 601_ EKPTA 606_ DAEAY 611_ VFTPN 616_ MICAG 621_ GEKGM 626_ DSCKG 631_ DSGGA 636_ FAVQD 641_ PNDKT 646_ KFYAA 651_ GLVSW 656_ GPQCG 661_ TYGLY 666_ TRVKN 671_ YVDWI 676_ MKTMQ 681_ENSTP
1: Component of the complement C1 complex, a multiprotein complex that initiates the classical pathway of the complement system, a cascade of proteins that leads to phagocytosis and breakdown of pathogens and signaling that strengthens the adaptive immune system (PubMed:11445589, PubMed:16169853, PubMed:417728, PubMed:467643, PubMed:6271784, PubMed:6282646, PubMed:6319179, PubMed:70787, PubMed:9422791). C1S is activated following association of the C1 complex with immunoglobulins (IgG or IgM) complexed with antigens to form antigen-antibody complexes on the surface of pathogens (PubMed:34155115). C1S is cleaved and activated by C1R to generate C1s subcomponent heavy and light chains (PubMed:11445589, PubMed:6271784). C1s subcomponent light chain then cleaves and activates C2 and C4, the next components of the classical complement pathway (PubMed:16169853, PubMed:467643, PubMed:6282646, PubMed:6319179, PubMed:6906228, PubMed:70787, PubMed:9422791)
2: Serine protease component of the complement C1 complex, which catalyzes cleavage and activation of C2 and C4, the next components of the classical complement pathway (PubMed:16169853, PubMed:22949645, PubMed:417728, PubMed:467643, PubMed:6282646, PubMed:6319179, PubMed:70787, PubMed:9422791). Also able to cleave C1 inhibitor (SERPING1) in vitro; additional evidence is however required to confirm this result in vivo (PubMed:16169853). Also cleaves IGFBP5 and thereby inhibits the trophic effects of IGF1 (PubMed:18930415)