title: Methylatable Signaling Helix Coordinated Inhibitory Receiver Domain in Sensor Kinase Modulates Environmental Stress Response in Bacillus Cereus.
abstract: σB, an alternative transcription factor, controls the response of the cell to a variety of environmental stresses in Bacillus cereus. Previously, we reported that RsbM negatively regulates σB through the methylation of RsbK, a hybrid sensor kinase, on a signaling helix (S-helix). However, RsbK comprises a C-terminal receiver (REC) domain whose function remains unclear. In this study, deletion of the C-terminal REC domain of RsbK resulted in high constitutive σB expression independent of environmental stimuli. Thus, the REC domain may serve as an inhibitory element. Mutagenic substitution was employed to modify the putative phospho-acceptor residue D827 in the REC domain of RsbK. The expression of RsbKD827N and RsbKD827E exhibited high constitutive σB, indicating that D827, if phosphorylatable, possibly participates in σB regulation. Bacterial two-hybrid analyses demonstrated that RsbK forms a homodimer and the REC domain interacts mainly with the histidine kinase (HK) domain and partly with the S-helix. In particular, co-expression of RsbM strengthens the interaction between the REC domain and the S-helix. Consistently, our structural model predicts a significant interaction between the HK and REC domains of the RsbK intradimer. Here, we demonstrated that coordinated the methylatable S-helix and the REC domain of RsbK is functionally required to modulate σB-mediated stress response in B. cereus and maybe ubiquitous in microorganisms encoded RsbK-type sensor kinases.
authors.affiliation: Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, Taiwan.
authors.forename: Jung-Chi
authors.initials: JC
authors.lastname: Chen
authors.affiliation: Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, Taiwan; Agricultural Biotechnology Center (ABC), National Chung Hsing University, Taichung, Taiwan.
authors.forename: Jyung-Hurng
authors.initials: JH
authors.lastname: Liu
authors.affiliation: Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, Taiwan.
authors.forename: Duen-Wei
authors.initials: DW
authors.lastname: Hsu
authors.affiliation: Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Tao-Yuan, Taiwan.
authors.forename: Jwu-Ching
authors.initials: JC
authors.lastname: Shu
authors.affiliation: Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan.
authors.forename: Chien-Yen
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, Taiwan.
authors.forename: Chien-Cheng
authors.initials: CC
authors.lastname: Chen
mesh_terms: D001409:Bacillus cereus / Q000378:metabolism* / Q000502:physiology*; D001426:Bacterial Proteins / Q000378:metabolism; D004777:Environment; D000071677:Histidine Kinase; D008745:Methylation; D010766:Phosphorylation / Q000502:physiology; D011494:Protein Kinases / Q000378:metabolism*; D017433:Protein Structure, Secondary / Q000502:physiology*; D017434:Protein Structure, Tertiary / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D013312:Stress, Physiological / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D014157:Transcription Factors; D011494:Protein Kinases; D000071677:Histidine Kinase