Involved in the activation cascade of caspases responsible for apoptosis execution. Cleaves caspase-1. Heterotetramer that consists of two anti-parallel arranged heterodimers, each one formed by a small and a large subunit. Widely expressed, with highest levels in spleen and lung. Moderate expression in heart and liver, low expression in skeletal muscle, kidney and testis. Not found in the brain. Belongs to the peptidase C14A family. 2 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.