A pyrin domain is a protein domain and a subclass of protein motif known as the death fold; it allows a pyrin domain containing protein to interact with other proteins that contain a pyrin domain. It is also known as a PYD or PAAD/DAPIN domain, and is distantly evolutionarily related to the Death domain family of protein domains. Proteins containing a pyrin domain are frequently involved in biological processes called inflammation and apoptosis. Proteins that possess a pyrin domain include intracellular microbial sensors called NOD-like receptors, and proteins associated with their function, such as PYCARD and certain fish caspases. A pyrin domain is a protein domain and a subclass of protein motif known as the death fold; it allows a pyrin domain containing protein to interact with other proteins that contain a pyrin domain. It is also known as a PYD or PAAD/DAPIN domain, and is distantly evolutionarily related to the Death domain family of protein domains. Proteins containing a pyrin domain are frequently involved in biological processes called inflammation and apoptosis. Proteins that possess a pyrin domain include intracellular microbial sensors called NOD-like receptors, and proteins associated with their function, such as PYCARD and certain fish caspases.