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. [provided by RefSeq, Aug 2012]