The protein encoded by this gene has structural and functional similarities to complement component 9 (C9).Like C9, this protein creates transmembrane tubules and is capable of lysing non-specifically a variety of target cells.This protein is one of the main cytolytic proteins of cytolytic granules, and it is known to be a key effector molecule for T-cell- and natural killer-cell-mediated cytolysis.Defects in this gene cause familial hemophagocytic lymphohistiocytosis type 2 (HPLH2), a rare and lethal autosomal recessive disorder of early childhood.Alternative splicing results in multiple transcript variants encoding the same protein.[provided by RefSeq] Synonyms: HPLH2, MGC65093, P1, PFP