該基因編碼的蛋白質是一種內源性鈣蛋白酶（鈣依賴半胱氨酸蛋白酶）抑制劑它由一個N-末端結構域L和四個重復的鈣蛋白酶抑制結構域（結構域1-4）組成，參與淀粉樣前體蛋白的蛋白水解。calpain/calpastatin系統參與許多膜融合事件，如神經囊泡胞吐、血小板和紅細胞聚集編碼的蛋白質也被認為會影響編碼結構蛋白或調節蛋白的基因的表達水平另外，還描述了編碼不同亞型的剪接轉錄變體[由RefSeq提供，2010年6月]
The protein encoded by this gene is an endogenous calpain (calcium-dependent cysteine protease) inhibitor. It consists of an N-terminal domain L and four repetitive calpain-inhibition domains (domains 1-4), and it is involved in the proteolysis of amyloid precursor protein. The calpain/calpastatin system is involved in numerous membrane fusion events, such as neural vesicle exocytosis and platelet and red-cell aggregation. The encoded protein is also thought to affect the expression levels of genes encoding structural or regulatory proteins. Alternatively spliced transcript variants encoding different isoforms have been described. [provided by RefSeq, Jun 2010]