NOD proteins include the apoptosis regulator APAF1 (apoptotic protease activating factor 1) and mammalian NOD-LRR proteins. NALP7, also known as PYPAF3, a member of the related PYRIN-containing APAF1-like proteins (PYPAFs/NALPs) is thought to play a crucial role in cell proliferation. NALP7 has a C-terminal leucine-rich repeat (LRR) region, an N-terminal Pyrin domain (PYD) followed by a NACHT domain, and a NACHT-associated domain. It is expressed in numerous tissues including uterus and ovary, with low levels in heart and brain. NALP7 inhibits caspase-1-dependent interleukin-1β secretion and is a feedback regulator of interleukin-1β secretion. Defects in the NALP7 gene are known to cause the formation of a hydatidiform mole (HYDM) and reduce the growth of carcinoma cell lines.