WW domain-binding protein 2 (WBP2) is a 261 amino acid protein expressed in most tissues. The WW domain is composed of 38 to 40 semi-conserved amino acids and is shared by various groups of proteins, including structural, regulatory and signaling proteins. The domain mediates protein-protein interactions through the binding of polyproline ligands. WBP2 binds to the WW domain of Yes-associated protein (YAP), WW domain containing E3 ubiquitin protein ligase 1 (AIP5) and WW domain containing E3 ubiquitin protein ligase 2 (AIP2). The gene encoding WBP2 is located on human chromosome 17, which comprises over 2.5% of the human genome and encodes over 1,200 genes, some of which are involved in tumor suppression and in the pathogenesis of Li-Fraumeni syndrome, early onset breast cancer and a predisposition to cancers of the ovary, colon, prostate gland and fallopian tubes.