A calpain-like activity insensitive to calpastatin in Drosophila melanogaster.
Calpains are neutral Ca2+-dependent cysteine proteases. In this study, we utilized casein zymography to detect such a proteolytic activity in Drosophila melanogaster extracts throughout the life of this organism. One calpain-like activity that was sensitive to the general cysteine protease inhibitors, E64 and calpain inhibitor I, but insensitive to the human calpain-specific inhibitor, calpastatin, is demonstrated. The relevance of this finding is discussed with respect to the absence of a corresponding Drosophila gene, homologous to the vertebrate calpastatin genes, as concluded from our unsuccessful attempts to clone such a gene and our Blast searches using the FlyBase. The mechanisms of Drosophila calpain regulation require further investigation. However, we suggest that single chain, non-heterodimeric calpains may be insensitive to calpastatin and that Drosophila cystatin-like molecules may play a role in negatively regulating Drosophila calpain.
Laval
Monique
M
Département de Biologie Cellulaire, Institut Jacques Monod, UMR 7592, CNRS/Universités Paris 6 et Paris 7, 2, place Jussieu, F-75251 Paris cedex 05, France. laval@infobiogen.fr
Pascal
Martial
M
D000818:Animals; D002135:Calcium-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D002154:Calpain / Q000037:antagonists & inhibitors* / Q000235:genetics; D003001:Cloning, Molecular; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D004331:Drosophila melanogaster / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D015723:Gene Library
D002135:Calcium-Binding Proteins; D015853:Cysteine Proteinase Inhibitors; C033668:calpastatin; D002154:Calpain