title: Specific cleavage of transcription factors by the thiol protease, m-calpain.
abstract: The intracellular nonlysosomal calcium-dependent cysteine protease, m-calpain, is shown to specifically cleave the bHLHzip transcription factor USF leaving the binding and dimerisation domains intact. The resultant protein is capable of efficient DNA binding but is no longer able to activate transcription. A surprisingly high proportion of other transcription factors tested, AP1 (c-Fos/c-Jun), Pit-1, Oct-1, CP1a and b, c-Myc, ATF/CREB, AP2 and AP3 but not Sp1, were similarly cleaved by m-calpain to produce specific partial digestion products. These properties make m-calpain a particularly useful protease for proteolytic studies of transcription factors and also raise the possibility that m-calpain may be involved in vivo in regulation of turnover or transcriptional activity of a number of transcription factors.
authors.affiliation: CSIRO Division of Biomolecular Engineering, Sydney Laboratory, North Ryde, NSW, Australia.
authors.forename: F
authors.initials: F
authors.lastname: Watt
authors.forename: P L
authors.initials: PL
authors.lastname: Molloy
mesh_terms: D001483:Base Sequence; D002118:Calcium / Q000378:metabolism; D002154:Calpain / Q000378:metabolism*; D002460:Cell Line; D004268:DNA-Binding Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D013379:Substrate Specificity; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D051720:Upstream Stimulatory Factors
chemical_list: D004268:DNA-Binding Proteins; D009838:Oligodeoxyribonucleotides; D014157:Transcription Factors; C497181:USF1 protein, human; D051720:Upstream Stimulatory Factors; D010450:Endopeptidases; D002154:Calpain; D002118:Calcium