title: Aspasing out metacaspases and caspases: proteases of many trades.
abstract: Execution of programmed cell death (PCD) in nonmetazoan organisms is morphologically different from apoptotic PCD in animals and lacks a number of key molecular components of apoptotic machinery, including caspases. Yet protozoan, fungal, and plant cells exhibit caspase-like proteolytic activities, which increase in a PCD-dependent manner. This poses a question whether nonmetazoan organisms contain structurally dissimilar proteases that functionally substitute for caspases. Putative ancestors of caspases, metacaspases, are candidates for this role; however, their distinct substrate specificity raises doubts. The identification of a common biological target of caspases and metacaspases and previously unknown functions unrelated to cell death of metacaspases provide new food for thought.
authors.affiliation: Department of Plant Biology and Forest Genetics, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7080, SE-75007 Uppsala, Sweden. peter.bozhkov@vbsg.slu.se
authors.forename: Peter V
authors.initials: PV
authors.lastname: Bozhkov
authors.forename: Andrei P
authors.initials: AP
authors.lastname: Smertenko
authors.forename: Boris
authors.initials: B
authors.lastname: Zhivotovsky
mesh_terms: D017209:Apoptosis; D020169:Caspases; D056890:Eukaryota; D019143:Evolution, Molecular; D010447:Peptide Hydrolases; D013379:Substrate Specificity
chemical_list: D010447:Peptide Hydrolases; D020169:Caspases