gC1qcontaining

gC1q-containing refers to proteins that harbor a globular C1q (gC1q) domain, a functional module derived from the globular head of the complement component C1q. This domain is found in a broad family of secreted proteins known as gC1q domain-containing (gC1qDC) proteins, which often participate in immune recognition, cell signaling, and extracellular interactions. In vertebrates, the best-characterized members are the C1q/TNF-related protein (CTRP) family and adiponectin (ADIPOQ), which share a C-terminal gC1q domain and typically feature an N-terminal collagen-like stalk that promotes oligomerization. Other gC1q-containing proteins include members of the C1QL (C1q-like) family, which can have roles in brain development and synaptic organization.

Structure and distribution: gC1q-containing proteins usually possess a signal peptide for secretion and, in many cases, a collagenous region that supports multimer formation. The gC1q domain itself forms a beta-sandwich structure that mediates interactions with receptors, ligands, or other proteins, enabling diverse signaling and adhesion functions. This domain architecture allows these proteins to act as adipokines, cytokine-like mediators, or extracellular matrix components.

Function: The functional repertoire of gC1q-containing proteins includes regulation of metabolism, inflammation, vascular function, and development. Adiponectin and CTRPs influence glucose and lipid metabolism and exhibit anti-inflammatory effects, partly through gC1q-mediated receptor interactions. In the nervous system, C1q-like proteins participate in synapse formation and maintenance.

Clinical relevance: Altered levels or signaling of gC1q-containing proteins have been linked to metabolic disorders, cardiovascular disease, and neurodevelopmental processes, making them topics of ongoing research for potential biomarkers and therapeutic targets.