Cloning and expression of the genes for calpains and calpastatins.

Calpain and calpastatin are known to be very widely distributed in animal cells. Although the physiological roles of calpain have not yet been clarified, the proteinase-proteinase inhibitor system has been suggested to play important roles in various cellular functions coupled with Ca2+ mobilization. By nucleotide sequencing of the cloned cDNAs, the primary structures of calpains and calpastatins have recently been disclosed. The expression of the genes for calpains and calpastatins in vitro as well as in vivo is being studied using cDNAs and their fragments. This paper reviews several topics on the recent progress of calpain research.