complement component 1s complement component 1s complement component 1s (ec 3.4.21.42, c1 esterase, activated complement c1s, complement c overbar 1r, c1s) is a protein involved in the complement system. c1s is part of the c1 complex. in humans, it is encoded by the c1s gene. c1savailable structurespdbortholog search: pdbe rcsb list of pdb id codes1elv, 1nzi, 4j1y, 4lmf, 4lor, 4los, 4lotidentifiersaliasesc1s, edspd2, complement c1sexternal idsomim: 120580 mgi: 3644269 homologene: 1314 genecards: c1s ec number3.4.21.42gene location (human)chr.chromosome 12 (human)band12p13.31start6,988,259 bpend7,071,032 bpgene location (mouse)chr.chromosome 6 (mouse)band6|6 f2start124,601,584 bpend124,613,044 bprna expression patternbgeehumanmouse (ortholog)top expressed inpericardiumright lobe of liverparietal pleuragallbladdergastric mucosatibial nerveleft uterine tubesynovial jointcanal of the cervixright coronary arterytop expressed inmorulawhite adipose tissuebone marrowadrenal glandurinary bladderovarymirrorislet of langerhanssuperior frontal gyrusspleenmore reference expression databiogpsmore reference expression datagene ontologymolecular function calcium ion binding peptidase activity serine-type peptidase activity protein binding hydrolase activity metal ion binding identical protein binding serine-type endopeptidase activity cellular component blood microparticle extracellular exosome extracellular region extracellular space biological process proteolysis complement activation, classical pathway immune system process innate immune response complement activation, lectin pathway complement activation regulation of complement activation sources:amigo / quickgoorthologsspecieshumanmouseentrez716317677ensemblensg00000182326ensmusg00000079343uniprotp09871q8cfg8refseq (mrna)nm_001734nm_201442nm_001346850nm_173864refseq (protein)np_001333779np_001725np_958850np_776289location (ucsc)chr 12: 6.99 – 7.07 mbchr 6: 124.6 – 124.61 mbpubmed searchwikidataview/edit humanview/edit mouse c1s cleaves c4 and c2, which eventually leads to the production of the classical pathway c3-convertase. classical pathway. (some labels are in polish.)