CCN protein (CCN)

CCN proteins are a family of six conserved, cysteine-rich matricellular proteins involved in the coordination of intercellular signaling by acting as dynamic modulators within the extracellular matrix[5][1][2]. Named after the first three discovered members—cysteine-rich protein 61 (CYR61/CCN1), connective tissue growth factor (CTGF/CCN2), and nephroblastoma overexpressed (NOV/CCN3)—the family now consists of six proteins: CCN1 (CYR61), CCN2 (CTGF), CCN3 (NOV), CCN4 (WISP1), CCN5 (WISP2), and CCN6 (WISP3)[5][7]. Structurally, CCN proteins have a modular organization that includes IGFBP, VWC, TSP-1, and a C-terminal cysteine knot (CT) domain, except for CCN5, which lacks the CT module[3]. CCN proteins orchestrate signaling networks essential for cell adhesion, migration, proliferation, differentiation, angiogenesis, and matrix remodeling, and they function in both physiological (e.g., development, wound healing) and pathological (e.g., cancer, fibrosis, cardiovascular disease) contexts by interacting with cell surface receptors (integrins, HSPGs, LRPs), other matrix proteins, and multiple growth factors[1][2][3][5][4][7]. Importantly, individual CCN proteins may have distinct as well as overlapping roles, and their spatiotemporal regulation allows fine-tuning of numerous biological processes[4][7].

Other names

Cysteine-rich protein familyCYR61/CTGF/NOV familyCellular communication network familyCYR61 (CCN1)Connective tissue growth factor (CTGF, CCN2)Nephroblastoma overexpressed (NOV, CCN3)Wnt1-inducible signaling pathway protein-1 (WISP1, CCN4)WISP2 (CCN5)WISP3 (CCN6)

Modulation of signaling pathways via binding to integrins, growth factors (such as TGF-β, BMPs, VEGF), and extracellular matrix components; indirect alteration of cell signaling, adhesion, migration, and matrix remodeling