Translocation protease protection

Protease protection provides a convenient means of discriminating between translation products translocated into microsomes, and therefore protected from added protease, and cytoplasmic species, which are degraded. 

The native calcium-binding protease, calpain, which translocates to the cytosolic surface of membranes upon calcium binding, was enriched from a membrane preparation and shown to elicit high levels of protection (56-67%) in mice (Hota-Mitchell ef a/., 1997). This protein was first implicated in protective immunity as the target of a CD4+ T cell clone that could arm peritoneal macrophages to kill schistosomula in vitro (Jankovic ef a/., 1996). The same clone administered intraperitoneally, conferred 65% protection on irradiated mice challenged via this route with cercariae and recombinant IL-2 (this is a very artificial test from which results should be treated with caution). The large subunit of calpain was subse-... 

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