Complement C1q subcomponent subunit C (C1QC)

Complement C1q subcomponent subunit C (C1QC) is one of the three polypeptide chains (A, B, and C) that form the C1q molecule of the complement system, a core component of the classical complement pathway. C1q is assembled from six heterotrimers (each containing C1qA, C1qB, and C1qC), resulting in a hexameric bouquet-shaped protein. The C1q C chain contains both an N-terminal collagen-like domain and a C-terminal globular recognition domain. The entire C1q molecule recognizes pathogens, apoptotic cells, and immune complexes and subsequently triggers complement activation by interacting with C1r and C1s proteases. Deficiency or dysfunction of C1q—including its C subunit—is strongly associated with immune diseases such as SLE and can also affect angiogenesis, neurodevelopment, and cancer progression. Therapeutic targeting of C1q or its subunits is under investigation for immunomodulation and complement-related disorders, with C1q levels also serving as clinical biomarkers.

Other names

C1QCComplement C1q subcomponent CComplement C1q subcomponent subunit CComplement component 1 q subcomponent, gamma polypeptideC1Q-CC1QGC1QD3

For research/therapeutics targeting C1q/C1QC: inhibition of classical complement activation, modulation of immune recognition and phagocytosis, blockade of interaction with immune complexes or cell surface receptors