NALP1 belongs to a family of cytoplasmic proteins that have been implicated in cell responses to apoptotic and inflammatory stimuli. It contains a caspase recruitment domain (CARD) in addition to a NACHT domain and leucine rich repeat (LRR). This protein interacts strongly with caspase 2 and weakly with caspase 9, as well as with Apaf-1. Transient overexpression of this gene in cultured cells was sufficient to induce apoptosis. NALP1 mRNA and protein expression levels in myeloid leukemia cells are increased following CREB (cAMP-response element binding protein) activation, suggesting that NALP1 may contribute to modulate the response of these cells to pro-inflammatory stimuli. Multiple alternatively spliced transcript variants encoding distinct isoforms have been found for NALP1.