title: Bacillus subtilis two-component system sensory kinase DegS is regulated by serine phosphorylation in its input domain.
abstract: Bacillus subtilis two-component system DegS/U is well known for the complexity of its regulation. The cytosolic sensory kinase DegS does not receive a single predominant input signal like most two-component kinases, instead it integrates a wide array of metabolic inputs that modulate its activity. The phosphorylation state of the response regulator DegU also does not confer a straightforward "on/off" response; it is fine-tuned and at different levels triggers different sub-regulons. Here we describe serine phosphorylation of the DegS sensing domain, which stimulates its kinase activity. We demonstrate that DegS phosphorylation can be carried out by at least two B. subtilis Hanks-type kinases in vitro, and this stimulates the phosphate transfer towards DegU. The consequences of this process were studied in vivo, using phosphomimetic (Ser76Asp) and non-phosphorylatable (Ser76Ala) mutants of DegS. In a number of physiological assays focused on different processes regulated by DegU, DegS S76D phosphomimetic mutant behaved like a strain with intermediate levels of DegU phosphorylation, whereas DegS S76A behaved like a strain with lower levels of DegU phophorylation. These findings suggest a link between DegS phosphorylation at serine 76 and the level of DegU phosphorylation, establishing this post-translational modification as an additional trigger for this two-component system.
authors.affiliation: Center for Systems Microbiology, Technical University of Denmark, Lyngby, Denmark.
authors.forename: Carsten
authors.initials: C
authors.lastname: Jers
authors.forename: Ahasanul
authors.initials: A
authors.lastname: Kobir
authors.forename: Elsebeth Oline
authors.initials: EO
authors.lastname: Søndergaard
authors.forename: Peter Ruhdal
authors.initials: PR
authors.lastname: Jensen
authors.forename: Ivan
authors.initials: I
authors.lastname: Mijakovic
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain / Q000235:genetics; D015169:Colony Count, Microbial; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D030781:Organisms, Genetically Modified; D010766:Phosphorylation; D010770:Phosphotransferases / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary / Q000502:physiology; D012694:Serine / Q000378:metabolism; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; C066496:DegS protein, Bacteria; C066497:DegU protein, Bacteria; D050505:Mutant Proteins; D012694:Serine; D010770:Phosphotransferases