WNT1-inducible-signaling pathway protein 1

WNT1-inducible-signaling pathway protein 1 (WISP-1), also known as CCN4, is a is_associated_with::matricellular protein that in humans is encoded by the WISP1 is_associated_with::gene.

Structure
WISP-1 is highly homologous to is_associated_with::CYR61 (CCN1) and is_associated_with::CTGF (CCN2), and is a member of the CCN family of secreted, is_associated_with::extracellular matrix (ECM)-associated signaling proteins (is_associated_with::CCN intercellular signaling protein). The CCN family of proteins shares a common molecular protein structure, characterized by an N-terminal secretory signal peptide followed by four distinct domains with homologies to insulin-like growth factor binding protein (IGFBP), von Willebrand type C repeats (vWC), thrombospondin type 1 repeat (TSR), and a is_associated_with::cysteine knot motif within the C-terminal (CT) domain. This family of proteins regulates diverse cellular functions, including is_associated_with::cell adhesion, migration, proliferation, differentiation, and survival.

Role in bone development
WISP-1 promotes is_associated_with::mesenchymal cell proliferation and is_associated_with::osteoblastic differentiation, and represses chondrocytic differentiation. WISP-1 binds BMP2 and enhances BMP2 function in is_associated_with::osteogenesis. These activities may be modulated by its direct binding to is_associated_with::decorin and is_associated_with::biglycan, two members of a family of small leucine-rich is_associated_with::proteoglycans present in the extracellular matrix of connective tissue.

Clinical significance
WISP-1 attenuates is_associated_with::p53-mediated is_associated_with::apoptosis in response to is_associated_with::DNA damage through activation of the Akt kinase, and inhibits is_associated_with::TNF-induced cell death in cardiomyocytes. Recombinant WISP-1 enhances ECM deposition in human fibroblasts, suggesting that it might play a role in matrix remodeling in vivo. WISP-1 is upregulated in human patients with is_associated_with::idiopathic is_associated_with::pulmonary fibrosis and in a mouse model of bleomycin-induced lung fibrosis. Orotracheal application of WISP-1 neutralizing antibodies to the lung ameliorates is_associated_with::bleomycin-induced lung fibrosis, raising the possibility that WISP-1 might be a potential target for anti-fibrotic therapy.

Expression of WISP-1 promotes tumor growth, and high WISP-1 expression correlates with advanced tumors of the breast, colon, and lung. WISP-1 appears to inhibit is_associated_with::metastasis although expression of a WISP-1 splicing variant lacking the VWC domain appears to enhance the invasive characteristic of is_associated_with::gastric carcinoma cells.