WISP-1 is a member of the CCN family of secreted cysteine rich regulatory proteins. It is expressed in the heart, kidney, lung, pancreas, placenta, ovary, small intestine and spleen. WISP-1 is a beta catenin regulated protein that can contribute to tumorigenesis and has also been shown to play a role in bone development and fracture repair. Human WISP-1 is a 38.1 kDa protein containing 346 amino acid residues. It is composed of four distinct structural domains (modules), the IGF binding protein (IGFBP) domain, the von Willebrand Factor C (VWFC) domain, the thrombospondin type-1 repeat (TSP type-1) domain, and a C-terminal cystine knot-like (CTCK) domain.