Search Results

Overview

Uniprot IDQ07021
Protein NameComplement component 1 Q subcomponent-binding protein, mitochondrial
Gene NameC1QBP
OrganismHomo sapiens

Kla Sites from experimental identification

Position Flanking peptide
179 VIKNDDGKKALVLDC
91 DFLSDEIKEERKIQK

Function

Multifunctional and multicompartmental protein involved in inflammation and infection processes, ribosome biogenesis, protein synthesis in mitochondria, regulation of apoptosis, transcriptional regulation and pre-mRNA splicing (PubMed:10022843, PubMed:10479529, PubMed:10722602, PubMed:11086025, PubMed:11859136, PubMed:15243141, PubMed:16140380, PubMed:16177118, PubMed:17881511, PubMed:18676636, PubMed:19004836, PubMed:19164550, PubMed:20810993, PubMed:21536856, PubMed:21544310, PubMed:22700724, PubMed:28942965, PubMed:8662673, PubMed:8710908, PubMed:9461517). At the cell surface is thought to act as an endothelial receptor for plasma proteins of the complement and kallikrein-kinin cascades (PubMed:10479529, PubMed:11859136, PubMed:8662673, PubMed:8710908). 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 (PubMed:20810993, PubMed:8195709). In complex with cytokeratin-1/KRT1 is a high affinity receptor for kininogen-1/HMWK (PubMed:21544310). 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 (PubMed:16140380, PubMed:22700724, PubMed:9461517). Signaling involved in inhibition of innate immune response is implicating the PI3K-AKT/PKB pathway (PubMed:16177118). Required for protein synthesis in mitochondria (PubMed:28942965). In mitochondrial translation may be involved in formation of functional 55S mitoribosomes; the function seems to involve its RNA-binding activity (By similarity). Acts as a RNA modification reader, which specifically recognizes and binds mitochondrial RNAs modified by C5-methylcytosine (m5C) in response to stress, and promotes recruitment of the mitochondrial degradosome complex, leading to their degradation (PubMed:39019044). 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 (By similarity). Involved in regulation of RNA splicing by inhibiting the RNA-binding capacity of SRSF1 and its phosphorylation (PubMed:10022843, PubMed:21536856). Is required for the nuclear translocation of splicing factor U2AF1L4 (By similarity). Involved in regulation of CDKN2A- and HRK-mediated apoptosis. Stabilizes mitochondrial CDKN2A isoform smARF (PubMed:17486078). May be involved in regulation of FOXC1 transcriptional activity and NFY/CCAAT-binding factor complex-mediated transcription (PubMed:15243141, PubMed:18676636). May play a role in antibacterial defense as it can bind to cell surface hyaluronan and inhibit Streptococcus pneumoniae hyaluronate lyase (PubMed:19004836). May be involved in modulation of the immune response; ligation by HCV core protein is resulting in suppression of interleukin-12 production in monocyte-derived dendritic cells (PubMed:11086025, PubMed:17881511). Involved in regulation of antiviral response by inhibiting RIGI- and IFIH1-mediated signaling pathways probably involving its association with MAVS after viral infection (PubMed:19164550). Acts as a regulator of DNA repair via homologous recombination by inhibiting the activity of MRE11: interacts with unphosphorylated MRE11 and RAD50 in absence of DNA damage, preventing formation and activity of the MRN complex. Following DNA damage, dissociates from phosphorylated MRE11, allowing formation of the MRN complex (PubMed:31353207)

Protein Sequence

10 MLPLLRCVPR 20 VLGSSVAGLR 30 AAAPASPFRQ 40 LLQPAPRLCT 50 RPFGLLSVRA 60 GSERRPGLLR 70 PRGPCACGCG 80 CGSLHTDGDK 90 AFVDFLSDEI 100 KEERKIQKHK 110 TLPKMSGGWE 120 LELNGTEAKL 130 VRKVAGEKIT 140 VTFNINNSIP 150 PTFDGEEEPS 160 QGQKVEEQEP 170 ELTSTPNFVV 180 EVIKNDDGKK 190 ALVLDCHYPE 200 DEVGQEDEAE 210 SDIFSIREVS 220 FQSTGESEWK 230 DTNYTLNTDS 240 LDWALYDHLM 250 DFLADRGVDN 260 TFADELVELS 270 TALEHQEYIT 280 FLEDLKSFVK SQ

Gene Ontology

Classification GO ID Description
Cellular Component GO:0009986 cell surface
Molecular Function GO:0003729 mRNA binding
Molecular Function GO:0005080 protein kinase C binding
Molecular Function GO:0003714 transcription corepressor activity
Molecular Function GO:0008134 transcription factor binding
Biological Process GO:0006915 apoptotic process
Biological Process GO:0006958 complement activation, classical pathway
Biological Process GO:0042256 cytosolic ribosome assembly
Biological Process GO:0006974 DNA damage response
Biological Process GO:0006351 DNA-templated transcription
Biological Process GO:0006955 immune response
Biological Process GO:0045087 innate immune response
Biological Process GO:0000957 mitochondrial RNA catabolic process
Biological Process GO:0006397 mRNA processing
Biological Process GO:0050687 negative regulation of defense response to virus
Biological Process GO:2000042 negative regulation of double-strand break repair via homologous recombination
Biological Process GO:0032695 negative regulation of interleukin-12 production
Biological Process GO:0039534 negative regulation of MDA-5 signaling pathway
Biological Process GO:0048025 negative regulation of mRNA splicing, via spliceosome
Biological Process GO:0039536 negative regulation of RIG-I signaling pathway
Biological Process GO:0000122 negative regulation of transcription by RNA polymerase II
Biological Process GO:0032689 negative regulation of type II interferon production
Biological Process GO:0043491 phosphatidylinositol 3-kinase/protein kinase B signal transduction
Biological Process GO:0043065 positive regulation of apoptotic process
Biological Process GO:0045785 positive regulation of cell adhesion
Biological Process GO:2000510 positive regulation of dendritic cell chemotaxis
Biological Process GO:0070131 positive regulation of mitochondrial translation
Biological Process GO:0090023 positive regulation of neutrophil chemotaxis
Biological Process GO:0051897 positive regulation of phosphatidylinositol 3-kinase/protein kinase B signal transduction
Biological Process GO:1900026 positive regulation of substrate adhesion-dependent cell spreading
Biological Process GO:1901165 positive regulation of trophoblast cell migration
Biological Process GO:0030449 regulation of complement activation
Biological Process GO:0008380 RNA splicing
Cellular Component GO:0005737 cytoplasm
Cellular Component GO:0005829 cytosol
Cellular Component GO:0005615 extracellular space
Cellular Component GO:0098982 GABA-ergic synapse
Cellular Component GO:0098978 glutamatergic synapse
Cellular Component GO:0016020 membrane
Cellular Component GO:0005759 mitochondrial matrix
Cellular Component GO:0005739 mitochondrion
Cellular Component GO:0005730 nucleolus
Cellular Component GO:0005634 nucleus
Cellular Component GO:0005886 plasma membrane
Cellular Component GO:0048786 presynaptic active zone
Molecular Function GO:0031690 adrenergic receptor binding
Molecular Function GO:0062153 C5-methylcytidine-containing RNA reader activity
Molecular Function GO:0001849 complement component C1q complex binding
Molecular Function GO:0004857 enzyme inhibitor activity
Molecular Function GO:0005540 hyaluronic acid binding
Molecular Function GO:0030984 kininogen binding
Molecular Function GO:0097177 mitochondrial ribosome binding

Reference

[1] Yang Z, Yan C, Ma J, Peng P, Ren X et al.. Lactylome analysis suggests lactylation-dependent mechanisms of metabolic adaptation in hepatocellular carcinoma.. Nat Metab 5(1):61-79. 2023 Jan. PMID: 36593272.

[2] Shi CM, Wang QC, Li XL, Yang YH, Tang XY et al.. Global Profiling of Protein Lactylation in Human Hippocampi.. Proteomics Clin Appl 19(2):e202400061. 2025 Mar. PMID: 39610256.