The NALP family consists of cytoplasmic proteins within the larger CATERPILLER protein family. There exist in short forms (such as NALP4) and long forms (NALP1). NALP proteins include the apoptosis regulator apoptotic protease activating factor 1 (APAF1) and mammalian NOD-LRR proteins, and are thought to play a role in the inflammation and reproduction processes.
