Immediate-early protein playing a role in various cellular processes including proliferation, adhesion, migration, differentiation and survival (PubMed:15181016, PubMed:15611078, PubMed:12695522, PubMed:21344378, PubMed:12050162). Acts by binding to integrins or membrane receptors such as NOTCH1 (PubMed:12695522, PubMed:21344378, PubMed:15611078). Essential regulator of hematopoietic stem and progenitor cell function (PubMed:17463287). Inhibits myogenic differentiation through the activation of Notch-signaling pathway (PubMed:12050162). Inhibits vascular smooth muscle cells proliferation by increasing expression of cell-cycle regulators such as CDKN2B or CDKN1A independently of TGFB1 signaling (PubMed:20139355). Ligand of integrins ITGAV:ITGB3 and ITGA5:ITGB1, acts directly upon endothelial cells to stimulate pro-angiogenic activities and induces angiogenesis. In endothelial cells, supports cell adhesion, induces directed cell migration (chemotaxis) and promotes cell survival (PubMed:12695522). Also plays a role in cutaneous wound healing acting as integrin receptor ligand. Supports skin fibroblast adhesion through ITGA5:ITGB1 and ITGA6:ITGB1 and induces fibroblast chemotaxis through ITGAV:ITGB5. Seems to enhance bFGF-induced DNA synthesis in fibroblasts (PubMed:15611078). Involved in bone regeneration as a negative regulator (By similarity). Enhances the articular chondrocytic phenotype, whereas it repressed the one representing endochondral ossification (PubMed:21871891). Impairs pancreatic beta-cell function, inhibits beta-cell proliferation and insulin secretion (By similarity). Plays a role as negative regulator of endothelial pro-inflammatory activation reducing monocyte adhesion, its anti-inflammatory effects occur secondary to the inhibition of NF-kappaB signaling pathway (PubMed:21063504). Contributes to the control and coordination of inflammatory processes in atherosclerosis (By similarity). Attenuates inflammatory pain through regulation of IL1B- and TNF-induced MMP9, MMP2 and CCL2 expression. Inhibits MMP9 expression through ITGB1 engagement (PubMed:21871891). Interacts with FBLN1. Interacts (via CTCK domain) with NOTCH1 (via the EGF-like repeat region) (PubMed:12050162). Interacts with GJA1/CX43 (PubMed:15181016, PubMed:15213231). Interacts with ITGA5:ITGB1, ITGAV:ITGB3 and ITGAV:ITGB5 (PubMed:12695522, PubMed:15611078). Interacts with ZDHHC22; the interaction may lead to CCN3 palmitoylation (By similarity). Localizes at the gap junction in presence of GJA1. Expressed in endiothelial cells (at protein level) (PubMed:21063504). Expressed in bone marrow, thymic cells and nephroblastoma. Increased expression in Wilms tumor of the stromal type. Expressed in primitive compartments of umbilical vein cord. Expression is down-regulated by WT1. Expression is down-regulated by pro-inflammatory stimuli such as TNF or IL1B (PubMed:24722330, PubMed:21063504). Expression is induced by laminar shear stress and statins (PubMed:21063504). May be palmitoylated on Cys-244, which is important for extracellular secretion. Belongs to the CCN family.