Names & Taxonomy

Uniprot ID:
Q07021
Entry Name:
C1QBP_HUMAN
Status:
reviewed
Protein Names:
Complement component 1 Q subcomponent-binding protein, mitochondrial (ASF/SF2-associated protein p32) (Glycoprotein gC1qBP) (C1qBP) (Hyaluronan-binding protein 1) (Mitochondrial matrix protein p32) (gC1q-R protein) (p33)
Gene Names:
C1QBP GC1QBP HABP1 SF2P32
Gene Names Primary:
C1QBP
Organism:
Homo sapiens (Human)

Structure

Length:
282
Sequence:
MLPLLRCVPRVLGSSVAGLRAAAPASPFRQLLQPAPRLCTRPFGLLSVRAGSERRPGLLRPRGPCACGCGCGSLHTDGDKAFVDFLSDEIKEERKIQKHKTLPKMSGGWELELNGTEAKLVRKVAGEKITVTFNINNSIPPTFDGEEEPSQGQKVEEQEPELTSTPNFVVEVIKNDDGKKALVLDCHYPEDEVGQEDEAESDIFSIREVSFQSTGESEWKDTNYTLNTDSLDWALYDHLMDFLADRGVDNTFADELVELSTALEHQEYITFLEDLKSFVKSQ
Proteomes:
UP000005640

Subcellular location

Subcellular Location:
Mitochondrion matrix. Nucleus. Cell membrane; Peripheral membrane protein; Extracellular side. Secreted. Cytoplasm. Nucleus, nucleolus. Note=Seems to be predominantly localized to mitochondria. Secreted by activated lymphocytes.

Function

Function:
Is believed to be a multifunctional and multicompartmental protein involved in inflammation and infection processes, ribosome biogenesis, regulation of apoptosis, transcriptional regulation and pre-mRNA splicing. At the cell surface is thought to act as an endothelial receptor for plasma proteins of the complement and kallikrein-kinin cascades. Putative receptor for C1q; specifically binds to the globular "heads" of C1q thus inhibiting C1; may perform the receptor function through a complex with C1qR/CD93. In complex with cytokeratin-1/KRT1 is a high affinity receptor for kininogen-1/HMWK. Can also bind other plasma proteins, such as coagulation factor XII leading to its autoactivation. May function to bind initially fluid kininogen-1 to the cell membrane. The secreted form may enhance both extrinsic and intrinsic coagulation pathways. It is postulated that the cell surface form requires docking with transmembrane proteins for downstream signaling which might be specific for a cell-type or response. By acting as C1q receptor is involved in chemotaxis of immature dendritic cells and neutrophils and is proposed to signal through CD209/DC-SIGN on immature dendritic cells, through integrin alpha-4/beta-1 during trophoblast invasion of the decidua, and through integrin beta-1 during endothelial cell adhesion and spreading. Signaling involved in inhibition of innate immune response is implicating the PI3K-AKT/PKB pathway. In mitochondrial translation may be involved in formation of functional 55S mitoribosomes; the function seems to involve its RNA-binding activity. May be involved in the nucleolar ribosome maturation process; the function may involve the exchange of FBL for RRP1 in the association with pre-ribosome particles. Involved in regulation of RNA splicing by inhibiting the RNA-binding capacity of SRSF1 and its phosphorylation. Is required for the nuclear translocation of splicing factor U2AF1L4. Involved in regulation of CDKN2A- and HRK-mediated apoptosis. Stabilizes mitochondrial CDKN2A isoform smARF. May be involved in regulation of FOXC1 transcriptional activity and NFY/CCAAT-binding factor complex-mediated transcription. In infection processes acts as an attachment site for microbial proteins, including Listeria monocytogenes internalin B and Staphylococcus aureus protein A. May play a role in antibacterial defense as it can bind to cell surface hyaluronan and inhibit Streptococcus pneumoniae hyaluronate lyase. Involved in replication of Rubella virus. May be involved in modulation of the immune response; ligation by HCV core protein is resulting in suppresion of interleukin-12 production in monocyte-derived dendritic cells. Involved in regulation of antiviral response by inhibiting DDX58- and IFIH1-mediated signaling pathways probably involving its association with MAVS after viral infection. Involved in HIV-1 replication, presumably by contributing to splicing of viral RNA.
Cross Reference Drug Bank:
DB08818
Gene Ontology Go:
cell surface
cytoplasm
cytosol
extracellular space
membrane
mitochondrial matrix
mitochondrion
nucleolus
nucleus
plasma membrane
adrenergic receptor binding
complement component C1q binding
hyaluronic acid binding
kininogen binding
mitochondrial ribosome binding
mRNA binding
transcription corepressor activity
transcription factor binding
apoptotic process
blood coagulation
blood coagulation, intrinsic pathway
complement activation, classical pathway
immune response
innate immune response
mature ribosome assembly
mRNA processing
negative regulation of defense response to virus
negative regulation of interferon-gamma production
negative regulation of interleukin-12 production
negative regulation of MDA-5 signaling pathway
negative regulation of mRNA splicing, via spliceosome
negative regulation of RIG-I signaling pathway
negative regulation of transcription from RNA polymerase II promoter
phosphatidylinositol 3-kinase signaling
positive regulation of apoptotic process
positive regulation of cell adhesion
positive regulation of dendritic cell chemotaxis
positive regulation of mitochondrial translation
positive regulation of neutrophil chemotaxis
positive regulation of protein kinase B signaling
positive regulation of substrate adhesion-dependent cell spreading
positive regulation of trophoblast cell migration
regulation of complement activation
RNA splicing
transcription, DNA-templated
viral process
Gene Ontology Biological Process:
apoptotic process
blood coagulation
blood coagulation, intrinsic pathway
complement activation, classical pathway
immune response
innate immune response
mature ribosome assembly
mRNA processing
negative regulation of defense response to virus
negative regulation of interferon-gamma production
negative regulation of interleukin-12 production
negative regulation of MDA-5 signaling pathway
negative regulation of mRNA splicing, via spliceosome
negative regulation of RIG-I signaling pathway
negative regulation of transcription from RNA polymerase II promoter
phosphatidylinositol 3-kinase signaling
positive regulation of apoptotic process
positive regulation of cell adhesion
positive regulation of dendritic cell chemotaxis
positive regulation of mitochondrial translation
positive regulation of neutrophil chemotaxis
positive regulation of protein kinase B signaling
positive regulation of substrate adhesion-dependent cell spreading
positive regulation of trophoblast cell migration
regulation of complement activation
RNA splicing
transcription, DNA-templated
viral process
Gene Ontology Molecular Function:
adrenergic receptor binding
complement component C1q binding
hyaluronic acid binding
kininogen binding
mitochondrial ribosome binding
mRNA binding
transcription corepressor activity
transcription factor binding
Gene Ontology Cellular Component:
cell surface
cytoplasm
cytosol
extracellular space
membrane
mitochondrial matrix
mitochondrion
nucleolus
nucleus
plasma membrane
Keywords:
3D-structure
Acetylation
Adaptive immunity
Apoptosis
Cell membrane
Complement pathway
Complete proteome
Cytoplasm
Direct protein sequencing
Host-virus interaction
Immunity
Innate immunity
Membrane
Mitochondrion
Nucleus
Phosphoprotein
Reference proteome
Ribosome biogenesis
Secreted
Transcription
Transcription regulation
Transit peptide
mRNA processing
mRNA splicing
Interacts With:
P27958; Q14004-2; Q8N726; Q64364; P00748; Q12948; O00198; P01042; Q7Z434; Q05513; Q15139; P04004; P67809

Publication

PubMed ID:
8262387 8195709 11278463 15489334 1830244 8662673 8567680 8900153 8710908 9191880 9305894 9233640 9461517 10479529 10022843 10747014 10722602 11086025 10823864 11493647 11859136 12034482 12833064 12574814 15031724 15243141 16177118 16721827 16537587 16140380 17881511 17693683 17486078 18676636 18669648 19004836 19164550 19690332 19608861 20810993 21269460 20950273 21536856 21544310 22700724 22238231 24275569 25944712 10097078