title: A complex of YlbF, YmcA and YaaT regulates sporulation, competence and biofilm formation by accelerating the phosphorylation of Spo0A.
abstract: Bacillus subtilis has adopted a bet-hedging strategy to ensure survival in changing environments. From a clonal population, numerous sub-populations can emerge, expressing different sets of genes that govern the developmental processes of sporulation, competence and biofilm formation. The master transcriptional regulator Spo0A controls the entry into all three fates and the production of the phosphorylated active form of Spo0A is precisely regulated via a phosphorelay, involving at least four proteins. Two proteins, YmcA and YlbF were previously shown to play an unidentified role in the regulation of biofilm formation, and in addition, YlbF was shown to regulate competence and sporulation. Using an unbiased proteomics screen, we demonstrate that YmcA and YlbF interact with a third protein, YaaT to form a tripartite complex. We show that all three proteins are required for proper establishment of the three above-mentioned developmental states. We show that the complex regulates the activity of Spo0A in vivo and, using in vitro reconstitution experiments, determine that they stimulate the phosphorelay, probably by interacting with Spo0F and Spo0B. We propose that the YmcA-YlbF-YaaT ternary complex is required to increase Spo0A~P levels above the thresholds needed to induce development.
authors.affiliation: Public Health Research Center, New Jersey Medical School, 225 Warren Street, Newark, NJ 07103, USA.
authors.forename: Valerie J
authors.initials: VJ
authors.lastname: Carabetta
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Tanner
authors.forename: Todd M
authors.initials: TM
authors.lastname: Greco
authors.forename: Melissa
authors.initials: M
authors.lastname: Defrancesco
authors.forename: Ileana M
authors.initials: IM
authors.lastname: Cristea
authors.forename: David
authors.initials: D
authors.lastname: Dubnau
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D015964:Gene Expression Regulation, Bacterial; D010766:Phosphorylation; D013171:Spores, Bacterial / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques
chemical_list: D001426:Bacterial Proteins; C080950:Spo0A protein, Bacillus subtilis; D014157:Transcription Factors