ID C1QA_BOVIN Reviewed; 244 AA. AC Q5E9E3; Q56JV0; DT 26-APR-2005, integrated into UniProtKB/Swiss-Prot. DT 15-MAR-2005, sequence version 1. DT 24-JAN-2024, entry version 120. DE RecName: Full=Complement C1q subcomponent subunit A; DE Flags: Precursor; GN Name=C1QA; OS Bos taurus (Bovine). OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; OC Eutheria; Laurasiatheria; Artiodactyla; Ruminantia; Pecora; Bovidae; OC Bovinae; Bos. OX NCBI_TaxID=9913; RN [1] RP NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA]. RX PubMed=16305752; DOI=10.1186/1471-2164-6-166; RA Harhay G.P., Sonstegard T.S., Keele J.W., Heaton M.P., Clawson M.L., RA Snelling W.M., Wiedmann R.T., Van Tassell C.P., Smith T.P.L.; RT "Characterization of 954 bovine full-CDS cDNA sequences."; RL BMC Genomics 6:166-166(2005). RN [2] RP NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA]. RC TISSUE=Lymphoid epithelium; RA Yu J., Meng Y., Wang Z., Hansen C., Li C., Moore S.S.; RT "Analysis of sequences obtained from constructed full-length bovine cDNA RT libraries."; RL Submitted (JAN-2005) to the EMBL/GenBank/DDBJ databases. RN [3] RP NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA]. RC STRAIN=Crossbred X Angus; TISSUE=Ileum; RG NIH - Mammalian Gene Collection (MGC) project; RL Submitted (SEP-2005) to the EMBL/GenBank/DDBJ databases. CC -!- FUNCTION: C1q associates with the proenzymes C1r and C1s to yield C1, CC the first component of the serum complement system. The collagen-like CC regions of C1q interact with the Ca(2+)-dependent C1r(2)C1s(2) CC proenzyme complex, and efficient activation of C1 takes place on CC interaction of the globular heads of C1q with the Fc regions of IgG or CC IgM antibody present in immune complexes. CC -!- SUBUNIT: C1 is a calcium-dependent trimolecular complex of C1q, R and S CC in the molar ration of 1:2:2. C1q subcomponent is composed of nine CC subunits, six of which are disulfide-linked dimers of the A and B CC chains, and three of which are disulfide-linked dimers of the C chain. CC Interacts (via C-terminus) with CD33; this interaction activates CD33 CC inhibitory motifs. Interacts with CR1 (via Sushi 24 and Sushi 25 CC domains). Antigen-bound IgM (via the Fc region) interacts with the CC globular domains of C1q component of the complement system, all three CC modules C1QA, C1QB and C1QC being involved in IgM binding; this CC interaction is multivalent. It initiates the classical complement CC pathway. {ECO:0000250|UniProtKB:P02745}. CC -!- SUBCELLULAR LOCATION: Secreted. CC -!- PTM: O-linked glycans are Glc-Gal disaccharides typically found as CC secondary modifications of hydroxylated lysines in collagen-like CC domains. {ECO:0000250|UniProtKB:P02745}. CC -!- PTM: Proline residues in the collagen-like domain motif, GXPG, are CC typically 4-hydroxylated. {ECO:0000250|UniProtKB:P02745}. CC --------------------------------------------------------------------------- CC Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms CC Distributed under the Creative Commons Attribution (CC BY 4.0) License CC --------------------------------------------------------------------------- DR EMBL; BT020977; AAX08994.1; -; mRNA. DR EMBL; AY911382; AAW82145.1; -; mRNA. DR EMBL; BC105345; AAI05346.1; -; mRNA. DR RefSeq; NP_001014945.1; NM_001014945.2. DR RefSeq; XP_005203271.1; XM_005203214.3. DR AlphaFoldDB; Q5E9E3; -. DR SMR; Q5E9E3; -. DR STRING; 9913.ENSBTAP00000009415; -. DR GlyCosmos; Q5E9E3; 4 sites, No reported glycans. DR PaxDb; 9913-ENSBTAP00000009415; -. DR Ensembl; ENSBTAT00000009415.3; ENSBTAP00000009415.2; ENSBTAG00000007153.4. DR Ensembl; ENSBTAT00000040146.4; ENSBTAP00000039925.3; ENSBTAG00000007153.4. DR GeneID; 534961; -. DR KEGG; bta:534961; -. DR CTD; 712; -. DR VEuPathDB; HostDB:ENSBTAG00000007153; -. DR VGNC; VGNC:26616; C1QA. DR eggNOG; ENOG502RZM2; Eukaryota. DR GeneTree; ENSGT00940000162143; -. DR HOGENOM; CLU_001074_0_2_1; -. DR InParanoid; Q5E9E3; -. DR OMA; MEGPQGW; -. DR OrthoDB; 3683851at2759; -. DR TreeFam; TF329591; -. DR Reactome; R-BTA-166663; Initial triggering of complement. DR Reactome; R-BTA-173623; Classical antibody-mediated complement activation. DR Reactome; R-BTA-977606; Regulation of Complement cascade. DR Proteomes; UP000009136; Chromosome 2. DR Bgee; ENSBTAG00000007153; Expressed in lung and 107 other cell types or tissues. DR GO; GO:0005581; C:collagen trimer; IEA:UniProtKB-KW. DR GO; GO:0062167; C:complement component C1q complex; IEA:Ensembl. DR GO; GO:0098794; C:postsynapse; IEA:Ensembl. DR GO; GO:0048143; P:astrocyte activation; IEA:Ensembl. DR GO; GO:0006958; P:complement activation, classical pathway; IEA:UniProtKB-KW. DR GO; GO:0150062; P:complement-mediated synapse pruning; IEA:Ensembl. DR GO; GO:0045087; P:innate immune response; IEA:UniProtKB-KW. DR GO; GO:0001774; P:microglial cell activation; IEA:Ensembl. DR GO; GO:0016322; P:neuron remodeling; IEA:Ensembl. DR GO; GO:0150064; P:vertebrate eye-specific patterning; IEA:Ensembl. DR Gene3D; 2.60.120.40; -; 1. DR InterPro; IPR001073; C1q_dom. DR InterPro; IPR008160; Collagen. DR InterPro; IPR008983; Tumour_necrosis_fac-like_dom. DR PANTHER; PTHR15427:SF26; COMPLEMENT C1Q SUBCOMPONENT SUBUNIT A; 1. DR PANTHER; PTHR15427; EMILIN ELASTIN MICROFIBRIL INTERFACE-LOCATED PROTEIN ELASTIN MICROFIBRIL INTERFACER; 1. DR Pfam; PF00386; C1q; 1. DR Pfam; PF01391; Collagen; 1. DR PRINTS; PR00007; COMPLEMNTC1Q. DR SMART; SM00110; C1Q; 1. DR SUPFAM; SSF49842; TNF-like; 1. DR PROSITE; PS50871; C1Q; 1. PE 2: Evidence at transcript level; KW Collagen; Complement pathway; Disulfide bond; Glycoprotein; Hydroxylation; KW Immunity; Innate immunity; Reference proteome; Repeat; Secreted; Signal. FT SIGNAL 1..22 FT /evidence="ECO:0000255" FT CHAIN 23..244 FT /note="Complement C1q subcomponent subunit A" FT /id="PRO_0000003516" FT DOMAIN 31..109 FT /note="Collagen-like" FT DOMAIN 110..244 FT /note="C1q" FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00368" FT REGION 28..94 FT /note="Disordered" FT /evidence="ECO:0000256|SAM:MobiDB-lite" FT MOD_RES 39 FT /note="4-hydroxyproline" FT /evidence="ECO:0000250|UniProtKB:P02745" FT MOD_RES 45 FT /note="4-hydroxyproline" FT /evidence="ECO:0000250|UniProtKB:P02745" FT MOD_RES 48 FT /note="5-hydroxylysine" FT /evidence="ECO:0000250|UniProtKB:P02745" FT MOD_RES 54 FT /note="4-hydroxyproline" FT /evidence="ECO:0000250|UniProtKB:P02745" FT MOD_RES 57 FT /note="4-hydroxyproline" FT /evidence="ECO:0000250|UniProtKB:P02745" FT MOD_RES 67 FT /note="5-hydroxylysine" FT /evidence="ECO:0000250|UniProtKB:P02745" FT MOD_RES 73 FT /note="4-hydroxyproline" FT /evidence="ECO:0000250|UniProtKB:P02745" FT MOD_RES 79 FT /note="4-hydroxyproline" FT /evidence="ECO:0000250|UniProtKB:P02745" FT MOD_RES 85 FT /note="4-hydroxyproline" FT /evidence="ECO:0000250|UniProtKB:P02745" FT MOD_RES 100 FT /note="5-hydroxylysine" FT /evidence="ECO:0000250|UniProtKB:P02745" FT CARBOHYD 48 FT /note="O-linked (Gal...) hydroxylysine" FT /evidence="ECO:0000250|UniProtKB:P02745" FT CARBOHYD 67 FT /note="O-linked (Gal...) hydroxylysine" FT /evidence="ECO:0000250|UniProtKB:P02745" FT CARBOHYD 100 FT /note="O-linked (Gal...) hydroxylysine" FT /evidence="ECO:0000250|UniProtKB:P02745" FT CARBOHYD 146 FT /note="N-linked (GlcNAc...) asparagine" FT /evidence="ECO:0000255" FT DISULFID 26 FT /note="Interchain (with C-26 in B chain)" FT /evidence="ECO:0000250" SQ SEQUENCE 244 AA; 25802 MW; C7D5B699E501D00D CRC64; MEAPRGWLVI SVLAISLASS VTEDVCRAPD GTHGSAGIPG RPGRPGLKGE RGEPGAPAIQ TGIRGLKGDQ GDPGPPGNPG RMGYPGPSGP MGPAGLPGLK GTKGSPGNIK DQPRPAFSAV GPNSVSRDNV VVFGKVITNQ ENVYQNNTGR FRCSVPGYYY FTFQVVSNWD ICLSIRSSRR DQIQPLGFCD FNSKGFFQVV SGGTVLHLQQ GDQVWIEKDP SKGRIYHGSE ADSIFSGFLI FPSA //