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Calpains: Intact and active?
Author(s) -
Johnson Gail V. W.,
Guttmann Rodney P.
Publication year - 1997
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/bies.950191111
Subject(s) - calpain , proteases , microbiology and biotechnology , enzyme , biochemistry , calpastatin , calcium , intracellular , chemistry , cytoskeleton , cleavage (geology) , biology , cell , organic chemistry , paleontology , fracture (geology)
Calpains are a family of calcium‐dependent thiol‐proteases which are proposed to be involved in many physiological processes as well as pathological conditions. Calpains are likely to be involved in processing of numerous enzymes and cytoskeletal components, thereby linking their activity to a variety of intracellular events. Although widely studied, the precise mechanism(s) involved in calpain activation and activity in vivo remain poorly understood. Initial studies suggested that calpain exists primarily as an inactive proenzyme that required autolytic cleavage for activation. It was also hypothesized that calpain associated with membrane phospholipids, serving to increase calcium sensitivity, facilitating autolytic conversion and thus activating the enzyme. These hypotheses, however, have not been universally accepted and there is increasing evidence that intact, non‐autolyzed calpain is the physiologically active calpain form.