RET and brain ischemia: The role of calpains in Ret51 cleavage is supported by the following pieces of evidence: (i) calpain inhibitors prevented the excitotoxicity- and OGD-induced downregulation of total Ret51; (ii) Ret51 cleavage under excitotoxic conditions and in the in vitro and in vivo models of brain ischemia was correlated with an increase in calpain activity; (iii) inhibition of calpains prevented the glutamate-evoked formation of a Ret51 cleavage product; and (iv) several putative calpain cleavage sites, located in intracellular sequences of Ret51, were identified by the GPS-CCD program.