CTRPs

CTRPs, or C1q/tumor necrosis factor-related proteins, are a family of secreted, adipokine-like proteins that share structural features with adiponectin. They are encoded by several genes in mammals, commonly designated CTRP1 through CTRP15, with expression patterns that include adipose tissue, skeletal muscle, liver, and heart. The proteins are synthesized with an N-terminal signal peptide, followed by a collagen-like domain and a C1q-like globular domain, enabling them to form homotrimers and higher-order multimeric complexes.

Functions and roles: CTRPs act as hormonal mediators that regulate energy metabolism, glucose and lipid homeostasis, insulin sensitivity, and inflammation. Many CTRPs influence insulin signaling and hepatic lipid metabolism in animal models; some exert anti-inflammatory effects, while others can promote inflammation depending on context. They also participate in cardiovascular and immune system regulation and may influence angiogenesis and adipose tissue remodeling.

Regulation and clinical relevance: CTRP expression is responsive to nutritional status, exercise, and hormonal signals. Levels are altered in obesity, type 2 diabetes, and cardiovascular disease, suggesting potential as biomarkers or therapeutic targets. Research continues to delineate the specific receptors, signaling pathways, and physiological roles of individual CTRPs.

See also: adiponectin, adipokines.