C1qb
entrez
29687
canonical
uniprot
P31721
canonical
ensembl
ENSRNOG00000012749
resolver
ensp
ENSRNOP00000017060
resolver
enst
ENSRNOT00000017060
resolver
genesymbol
C1qb
resolver
uniprot
G3V7N9
resolver
uniprot_entry
C1QB_RAT
resolver
uniprot_entry
G3V7N9_RAT
resolver
activity_regulation
ACTIVITY REGULATION: The C1Q subcomplex is inhibited by sulfated molecules, such as triterpenoid sulfates, heparan sulfate, or chondroitin sulfates. {ECO:0000250|UniProtKB:P02746}.
uniprot
proteins
amino_acid_sequence
MKTQWSEILTPLLLLLLGLLHVSWAQSSCTGSPGIPGVPGIPGVPGSDGKPGTPGIKGEKGLPGLAGDHGELGEKGDAGIPGIPGKVGPKGPVGPKGAPGPPGPRGPKGGSGDYKATQKVAFSALRTVNSALRPNQAIRFEKVITNVNDNYEPRSGKFTCKVPGLYYFTYHASSRGNLCVNIVRGRDRDRMQKVLTFCDYAQNTFQVTTGGVVLKLEQEEVVHLQATDKNSLLGVEGANSIFTGFLLFPDMDV
uniprot
proteins
function
FUNCTION: Core 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. The classical complement pathway is initiated by the C1Q subcomplex of the C1 complex, which specifically binds IgG or IgM immunoglobulins complexed with antigens, forming antigen-antibody complexes on the surface of pathogens: C1QA, together with C1QB and C1QC, specifically recognizes and binds the Fc regions of IgG or IgM via its C1q domain. Immunoglobulin-binding activates the proenzyme C1R, which cleaves C1S, initiating the proteolytic cascade of the complement system. The C1Q subcomplex is activated by a hexamer of IgG complexed with antigens, while it is activated by a pentameric IgM. The C1Q subcomplex also recognizes and binds phosphatidylserine exposed on the surface of cells undergoing programmed cell death, possibly promoting activation of the complement system. {ECO:0000250|UniProtKB:P02746}.
uniprot
proteins
mass_dalton
26589
uniprot
proteins
post_translational_modification
PTM: Hydroxylated on lysine and proline residues. Hydroxylated lysine residues can be glycosylated. Human C1Q contains up to 68.3 hydroxylysine-galactosylglucose residues and up to 2.5 hydroxylysine-galactose per molecule. Total percentage hydroxylysine residues glycosylated is 86.4%. {ECO:0000250|UniProtKB:P02746}.
uniprot
proteins
pubmed
7594503
uniprot
proteins
pubmed
8464426
uniprot
proteins
sequence_length
253
uniprot
proteins
subcellular_location
SUBCELLULAR LOCATION: Secreted {ECO:0000250|UniProtKB:P02746}. Cell surface {ECO:0000250|UniProtKB:P02746}. Note=Specifically binds IgG or IgM immunoglobulins complexed with antigens, forming antigen-antibody complexes on the surface of pathogens. {ECO:0000250|UniProtKB:P02746}.
uniprot
proteins