CTGF

CTGF, also called CCN2, is a heparin-binding matricellular protein of the CCN family rather than a true IGF-binding protein, despite its catalog position. Secreted by fibroblasts, endothelial cells and chondrocytes, it carries four conserved modules — an insulin-like growth factor binding protein-like domain, a von Willebrand factor type C repeat, a thrombospondin type 1 repeat and a cystine knot — through which it engages integrins, heparan sulfate proteoglycans and other receptors. CTGF is a principal downstream mediator of TGF-beta in fibroblasts, driving extracellular matrix deposition, myofibroblast differentiation, angiogenesis and chondrogenesis. Sustained CTGF expression is a hallmark of fibrotic disorders of skin, lung, liver and kidney, and anti-CTGF antibodies are in clinical development for fibrosis.