A sporulation membrane protein tethers the pro-sigmaK processing enzyme to its inhibitor and dictates its subcellular localization.
The developmental transcription factor sigmaK is derived from the inactive precursor protein pro-sigmaK by regulated proteolysis during the process of sporulation in the bacterium Bacillus subtilis. The putative pro-sigmaK processing enzyme SpoIVFB is a member of a family of membrane-embedded metalloproteases and is held inactive by two other integral membrane proteins, SpoIVFA and BofA. Herein we show that the processing enzyme and its two regulators exist in a multimeric complex that localizes to the membrane surrounding the developing spore (the forespore). We further show that one of the regulators, SpoIVFA, plays a central role in both the formation of this complex and its subcellular localization. Evidence is presented in support of a model in which SpoIVFA acts as a platform for bringing BofA and SpoIVFB together, whereby BofA inhibits pro-sigmaK processing until a signal has been received from the forespore.
Rudner
David Z
DZ
Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Losick
Richard
R
D001412:Bacillus subtilis; D001426:Bacterial Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D010450:Endopeptidases; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000502:physiology; D011499:Protein Processing, Post-Translational / Q000502:physiology*; D012097:Repressor Proteins; D017386:Sequence Homology, Amino Acid; D013171:Spores, Bacterial / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*
D001426:Bacterial Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C084190:sigma K; C074423:bofA protein, Bacillus subtilis; C071441:spoIVFA protein, Bacillus subtilis; D010450:Endopeptidases; C071442:spoIVFB protein, Bacillus subtilis