Background：WW domain-containing proteins are found in all eukaryotes and play an important role in the regulation of a wide variety of cellular functions such as protein degradation, transcription, and RNA splicing. This gene encodes a protein with two WW domains, a SARAH domain, and a coiled-coil region and is ubiquitously expressed in adult tissues. This protein binds to MST1 （mammalian sterile 20-like kinase 1） and promotes MST1-induced apoptosis. It has also been shown to bind to HAX1 （hematopoietic cell-specific protein 1 （HS1）-associated protein X-1） and to attenuate the anti-apoptotic effects of HAX1. Studies in human and mouse suggest this gene acts as a tumor suppressor.
