Complement component 1q subcomponent binding protein (C1QBP)

Complement component 1q subcomponent binding protein (C1QBP), also known as p32 or gC1qR, is a multifunctional, multicompartmental protein primarily localized in the mitochondrial matrix, but also found on the cell surface and in the nucleus. In the mitochondria, it plays a critical role in maintaining the architecture of the mitochondrial reticular network and regulating oxidative phosphorylation by assisting in the synthesis of mitochondrial-encoded proteins (UniProt Q07021). On the cell surface, it acts as a receptor for various ligands, including the C1q component of complement, high-molecular-weight kininogen, and several viral and bacterial proteins, thereby modulating inflammatory and infectious processes (PubMed: 28243101). C1QBP is significantly overexpressed in various cancers, including breast, colon, and lung adenocarcinomas, where it promotes tumor proliferation, migration, and resistance to apoptosis by shifting metabolic pathways toward glycolysis (PubMed: 25686121). Due to its selective translocation to the surface of tumor cells and tumor-associated macrophages, it has emerged as a promising target for site-specific drug delivery and immunotherapy. Therapeutic strategies currently under investigation include the use of tumor-homing peptides like LyP-1 and monoclonal antibodies to disrupt its pro-tumorigenic signaling or to deliver imaging and therapeutic payloads directly to the tumor microenvironment (PubMed: 30135338).

Other names

p32gC1qRHABP1Hyaluronan-binding protein 1Glycoprotein gC1qBPSF2-associated proteinTAPGC1QBP

Inhibition of C1QBP typically involves blocking its cell-surface interaction with ligands like C1q or kininogen to reduce inflammation and tumor growth, or utilizing it as a homing target for the delivery of cytotoxic agents to the mitochondrial compartment of malignant cells.