title: Self-reinforcing activation of a cell-specific transcription factor by proteolysis of an anti-sigma factor in B. subtilis.
abstract: The transcription factor sigma(F), which is activated in a cell-specific manner during sporulation in B. subtilis, is initially held in an inactive complex by the anti-sigma factor SpoIIAB. The anti-anti-sigma factor SpoIIAA reacts with SpoIIAB.sigma(F) to induce the release of free sigma(F) and free SpoIIAB. We now report that free SpoIIAB is subject to proteolysis and that it is protected from degradation by sigma(F) in the SpoIIAB.sigma(F) complex and by SpoIIAA in an alternative complex. Proteolysis requires residues located near the extreme C terminus of SpoIIAB and is dependent upon the ClpCP protease. The reaction of SpoIIAA with SpoIIAB.sigma(F) and the resulting degradation of newly released SpoIIAB could set up a self-reinforcing cycle that locks on the activation of sigma(F).
authors.affiliation: Department of Molecular and Cellular Biology, The Biological Laboratories, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Pan
authors.forename: D A
authors.initials: DA
authors.lastname: Garsin
authors.forename: R
authors.initials: R
authors.lastname: Losick
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000502:physiology*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D005786:Gene Expression Regulation; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D016415:Sequence Alignment; D012808:Sigma Factor / Q000378:metabolism*; D013171:Spores, Bacterial / Q000378:metabolism; D014157:Transcription Factors
chemical_list: D001426:Bacterial Proteins; C087481:ClpC protein, Bacteria; D004268:DNA-Binding Proteins; C064971:FliA protein, Bacteria; D006360:Heat-Shock Proteins; D046911:Macromolecular Substances; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D012808:Sigma Factor; D014157:Transcription Factors; C092468:spoIIR protein, Bacillus subtilis; C030069:spore-specific proteins, Bacillus