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Protein

Complement C1q subcomponent subunit B

Gene

C1qb

Organism
Rattus norvegicus (Rat)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

C1q associates with the proenzymes C1r and C1s to yield C1, the first component of the serum complement system. The collagen-like regions of C1q interact with the Ca2+-dependent C1r2C1s2 proenzyme complex, and efficient activation of C1 takes place on interaction of the globular heads of C1q with the Fc regions of IgG or IgM antibody present in immune complexes.

GO - Biological processi

  • aging Source: RGD
  • brain development Source: RGD
  • complement activation, classical pathway Source: UniProtKB-KW
  • immune response Source: RGD
  • innate immune response Source: UniProtKB-KW
  • response to glucocorticoid Source: RGD
  • response to organic substance Source: RGD
Complete GO annotation...

Keywords - Biological processi

Complement pathway, Immunity, Innate immunity

Names & Taxonomyi

Protein namesi
Recommended name:
Complement C1q subcomponent subunit B
Gene namesi
Name:C1qb
OrganismiRattus norvegicus (Rat)
Taxonomic identifieri10116 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresGliresRodentiaSciurognathiMuroideaMuridaeMurinaeRattus
Proteomesi
  • UP000002494 Componenti: Unplaced

Organism-specific databases

RGDi2229. C1qb.

Subcellular locationi

GO - Cellular componenti

  • collagen trimer Source: UniProtKB-KW
  • complement component C1 complex Source: RGD
Complete GO annotation...

Keywords - Cellular componenti

Secreted

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Signal peptidei1 – 25By similarityAdd BLAST25
ChainiPRO_000000352326 – 253Complement C1q subcomponent subunit BAdd BLAST228

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Modified residuei26Pyrrolidone carboxylic acidBy similarity1
Disulfide bondi29Interchain (with C-26 in chain A)
Modified residuei334-hydroxyprolineBy similarity1
Modified residuei364-hydroxyprolineBy similarity1
Modified residuei394-hydroxyprolineBy similarity1
Modified residuei514-hydroxyprolineBy similarity1
Modified residuei544-hydroxyprolineBy similarity1
Modified residuei575-hydroxylysineBy similarity1
Modified residuei605-hydroxylysineBy similarity1
Modified residuei634-hydroxyprolineBy similarity1
Modified residuei755-hydroxylysineBy similarity1
Modified residuei814-hydroxyprolineBy similarity1
Modified residuei844-hydroxyprolineBy similarity1
Modified residuei905-hydroxylysineBy similarity1
Modified residuei965-hydroxylysineBy similarity1
Modified residuei994-hydroxyprolineBy similarity1
Modified residuei1024-hydroxyprolineBy similarity1
Modified residuei1085-hydroxylysineBy similarity1

Post-translational modificationi

Hydroxylated on lysine and proline residues. Hydroxylated lysine residues can be glycosylated.

Keywords - PTMi

Disulfide bond, Glycoprotein, Hydroxylation, Pyrrolidone carboxylic acid

Proteomic databases

PaxDbiP31721.
PRIDEiP31721.

PTM databases

iPTMnetiP31721.
PhosphoSitePlusiP31721.

Expressioni

Tissue specificityi

Highest levels in spleen, lung and brain. Weaker expression in kidney and liver. In the spleen, localized mainly to the red pulp, in cells mainly of monocyte-macrophage lineage. In white pulp, localized in specific dendritic cells such as those from the periarteriolar lymphatic sheath (PALS).1 Publication

Interactioni

Subunit structurei

C1 is a calcium-dependent trimolecular complex of C1q, C1r and C1s in the molar ration of 1:2:2. C1q subcomponent is composed of nine subunits, six of which are disulfide-linked dimers of the a and B chains, and three of which are disulfide-linked dimers of the C chain. In addition to the major A:B and C:C dimer bands, rat, unlike human C1q, contained minor dimer species.

Protein-protein interaction databases

BioGridi248307. 1 interactor.
STRINGi10116.ENSRNOP00000017060.

Structurei

3D structure databases

ProteinModelPortaliP31721.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Domaini29 – 112Collagen-likeAdd BLAST84
Domaini115 – 253C1qPROSITE-ProRule annotationAdd BLAST139

Sequence similaritiesi

Contains 1 C1q domain.PROSITE-ProRule annotation
Contains 1 collagen-like domain.Curated

Keywords - Domaini

Collagen, Repeat, Signal

Phylogenomic databases

eggNOGiENOG410IWVM. Eukaryota.
ENOG4111MQB. LUCA.
HOGENOMiHOG000085653.
HOVERGENiHBG108220.
InParanoidiP31721.
KOiK03987.
PhylomeDBiP31721.

Family and domain databases

Gene3Di2.60.120.40. 1 hit.
InterProiIPR001073. C1q_dom.
IPR008160. Collagen.
IPR008983. Tumour_necrosis_fac-like_dom.
[Graphical view]
PfamiPF00386. C1q. 1 hit.
PF01391. Collagen. 2 hits.
[Graphical view]
PRINTSiPR00007. COMPLEMNTC1Q.
SMARTiSM00110. C1Q. 1 hit.
[Graphical view]
SUPFAMiSSF49842. SSF49842. 1 hit.
PROSITEiPS50871. C1Q. 1 hit.
[Graphical view]

Sequencei

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

P31721-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MKTQWSEILT PLLLLLLGLL HVSWAQSSCT GSPGIPGVPG IPGVPGSDGK
60 70 80 90 100
PGTPGIKGEK GLPGLAGDHG ELGEKGDAGI PGIPGKVGPK GPVGPKGAPG
110 120 130 140 150
PPGPRGPKGG SGDYKATQKV AFSALRTVNS ALRPNQAIRF EKVITNVNDN
160 170 180 190 200
YEPRSGKFTC KVPGLYYFTY HASSRGNLCV NIVRGRDRDR MQKVLTFCDY
210 220 230 240 250
AQNTFQVTTG GVVLKLEQEE VVHLQATDKN SLLGVEGANS IFTGFLLFPD

MDV
Length:253
Mass (Da):26,589
Last modified:November 1, 1995 - v2
Checksum:i1CB40622571BFC9B
GO

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
X71127 mRNA. Translation: CAA50440.1.
PIRiS49158.
RefSeqiNP_062135.1. NM_019262.1.
UniGeneiRn.6702.

Genome annotation databases

GeneIDi29687.
KEGGirno:29687.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
X71127 mRNA. Translation: CAA50440.1.
PIRiS49158.
RefSeqiNP_062135.1. NM_019262.1.
UniGeneiRn.6702.

3D structure databases

ProteinModelPortaliP31721.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi248307. 1 interactor.
STRINGi10116.ENSRNOP00000017060.

PTM databases

iPTMnetiP31721.
PhosphoSitePlusiP31721.

Proteomic databases

PaxDbiP31721.
PRIDEiP31721.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

GeneIDi29687.
KEGGirno:29687.

Organism-specific databases

CTDi713.
RGDi2229. C1qb.

Phylogenomic databases

eggNOGiENOG410IWVM. Eukaryota.
ENOG4111MQB. LUCA.
HOGENOMiHOG000085653.
HOVERGENiHBG108220.
InParanoidiP31721.
KOiK03987.
PhylomeDBiP31721.

Miscellaneous databases

PROiP31721.

Family and domain databases

Gene3Di2.60.120.40. 1 hit.
InterProiIPR001073. C1q_dom.
IPR008160. Collagen.
IPR008983. Tumour_necrosis_fac-like_dom.
[Graphical view]
PfamiPF00386. C1q. 1 hit.
PF01391. Collagen. 2 hits.
[Graphical view]
PRINTSiPR00007. COMPLEMNTC1Q.
SMARTiSM00110. C1Q. 1 hit.
[Graphical view]
SUPFAMiSSF49842. SSF49842. 1 hit.
PROSITEiPS50871. C1Q. 1 hit.
[Graphical view]
ProtoNetiSearch...

Entry informationi

Entry nameiC1QB_RAT
AccessioniPrimary (citable) accession number: P31721
Entry historyi
Integrated into UniProtKB/Swiss-Prot: July 1, 1993
Last sequence update: November 1, 1995
Last modified: November 2, 2016
This is version 117 of the entry and version 2 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

Complete proteome, Direct protein sequencing, Reference proteome

Documents

  1. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.