Sci. STKE, 29 August 2000
Apoptosis Calpain and Caspase Cross Talk
Caspases are cysteine proteases that regulate apoptosis, and some are activated by proteolytic cleavage of their proenzyme form by other caspases. However, Nakagawa and Yuan report that procaspase-12, localized at the cytoplasmic face of the endoplasmic reticulum (ER), is cleaved and activated by a noncaspase protease called calpain. Activation of caspase-12 in glial cells, in response to ER stress agents, was blocked when cells were treated with a calpain inhibitor. Activation of caspase-12 in these cells generated proteolytic caspase-12 fragments that were also observed in vitro by using purified proteins. The authors propose that activation of calpain by an increase in intracellular calcium, a condition that also promotes calpain translocation from the cytosol to membranes, may promote activation of caspase-12 and may play an important role in mediating neuronal degeneration.
Citation: Calpain and Caspase Cross Talk. Sci. STKE 2000, tw5 (2000).
Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882