C1QB
entrez
713
canonical
uniprot
P02746
canonical
ensembl
ENSG00000173369
resolver
ensp
ENSP00000404606
resolver
ensp
ENSP00000423689
resolver
ensp
ENSP00000512147
resolver
ensp
ENSP00000512148
resolver
ensp
ENSP00000512149
resolver
ensp
ENSP00000512150
resolver
ensp
ENSP00000567369
resolver
ensp
ENSP00000567371
resolver
ensp
ENSP00000567372
resolver
ensp
ENSP00000567373
resolver
ensp
ENSP00000622260
resolver
enst
ENST00000509305
resolver
enst
ENST00000695754
resolver
enst
ENST00000695755
resolver
enst
ENST00000695756
resolver
enst
ENST00000695757
resolver
enst
ENST00000897310
resolver
enst
ENST00000897312
resolver
enst
ENST00000897313
resolver
enst
ENST00000897314
resolver
enst
ENST00000952201
resolver
genesymbol
C1QB
resolver
hgnc
HGNC:1242
resolver
uniprot
D6R934
resolver
uniprot
Q5T959
resolver
uniprot
Q96H17
resolver
uniprot_entry
C1QB_HUMAN
resolver
uniprot_entry
D6R934_HUMAN
resolver
uniprot_sec
Q5T959
resolver
uniprot_sec
Q96H17
resolver
activity_regulation
ACTIVITY REGULATION: The C1Q subcomplex is inhibited by sulfated molecules, such as triterpenoid sulfates, heparan sulfate, or chondroitin sulfates. {ECO:0000269|PubMed:20548024, ECO:0000269|PubMed:6218163}.
uniprot
proteins
amino_acid_sequence
MMMKIPWGSIPVLMLLLLLGLIDISQAQLSCTGPPAIPGIPGIPGTPGPDGQPGTPGIKGEKGLPGLAGDHGEFGEKGDPGIPGNPGKVGPKGPMGPKGGPGAPGAPGPKGESGDYKATQKIAFSATRTINVPLRRDQTIRFDHVITNMNNNYEPRSGKFTCKVPGLYYFTYHASSRGNLCVNLMRGRERAQKVVTFCDYAYNTFQVTTGGMVLKLEQGENVFLQATDKNSLLGMEGANSIFSGFLLFPDMEA
uniprot
proteins
disease_involvement
DISEASE: C1q deficiency 2 (C1QD2) [MIM:620321]: An autosomal recessive disorder caused by impaired activation of the complement classical pathway. It generally leads to severe immune complex disease characterized by recurrent skin lesions, chronic infections, an increased risk of systemic lupus erythematosus, and glomerulonephritis. {ECO:0000269|PubMed:9476130}. Note=The disease is caused by variants affecting the gene represented in this entry.
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 (PubMed:12847249, PubMed:19006321, PubMed:24626930, PubMed:29449492, PubMed:3258649, PubMed:34155115, PubMed:6249812, PubMed:6776418). 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 (PubMed:12847249, PubMed:19006321, PubMed:24626930, PubMed:29449492, PubMed:3258649, PubMed:6776418). Immunoglobulin-binding activates the proenzyme C1R, which cleaves C1S, initiating the proteolytic cascade of the complement system (PubMed:29449492). The C1Q subcomplex is activated by a hexamer of IgG complexed with antigens, while it is activated by a pentameric IgM (PubMed:19706439, PubMed:24626930, PubMed:29449492). 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 (PubMed:18250442). {ECO:0000269|PubMed:12847249, ECO:0000269|PubMed:18250442, ECO:0000269|PubMed:19006321, ECO:0000269|PubMed:19706439, ECO:0000269|PubMed:24626930, ECO:0000269|PubMed:29449492, ECO:0000269|PubMed:3258649, ECO:0000269|PubMed:34155115, ECO:0000269|PubMed:6249812, ECO:0000269|PubMed:6776418}.
uniprot
proteins
mass_dalton
26722
uniprot
proteins
mutagenesis
MUTAGEN 88; /note="K->A: In LysB61; impaired ability to associate with C1R and C1S."; /evidence="ECO:0000269|PubMed:23650384
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:0000269|PubMed:486087, ECO:0000269|PubMed:6286235, ECO:0000269|PubMed:708376}.
uniprot
proteins
pubmed
12847249
uniprot
proteins
pubmed
12960167
uniprot
proteins
pubmed
15489334
uniprot
proteins
pubmed
16710414
uniprot
proteins
pubmed
16959974
uniprot
proteins
pubmed
18250442
uniprot
proteins
pubmed
19006321
uniprot
proteins
pubmed
19706439
uniprot
proteins
pubmed
20548024
uniprot
proteins
pubmed
23650384
uniprot
proteins
pubmed
24626930
uniprot
proteins
pubmed
29449492
uniprot
proteins
pubmed
2988513
uniprot
proteins
pubmed
3000358
uniprot
proteins
pubmed
3258649
uniprot
proteins
pubmed
34155115
uniprot
proteins
pubmed
486087
uniprot
proteins
pubmed
6208566
uniprot
proteins
pubmed
6218163
uniprot
proteins
pubmed
6249812
uniprot
proteins
pubmed
6286235
uniprot
proteins
pubmed
6776418
uniprot
proteins
pubmed
6952210
uniprot
proteins
pubmed
6981411
uniprot
proteins
pubmed
708376
uniprot
proteins
pubmed
9476130
uniprot
proteins
pubmed
9777412
uniprot
proteins
sequence_length
253
uniprot
proteins
subcellular_location
SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:18250442, ECO:0000269|PubMed:29449492, ECO:0000269|PubMed:708376}. Cell surface {ECO:0000269|PubMed:34155115}. Note=Specifically binds IgG or IgM immunoglobulins complexed with antigens, forming antigen-antibody complexes on the surface of pathogens. {ECO:0000269|PubMed:34155115}.
uniprot
proteins