García García Tránsito, Ventroux Magali, Derouiche Abderahmane, Bidnenko Vladimir, Correia Santos Sara, Henry Céline, Mijakovic Ivan, Noirot-Gros Marie-Françoise, Poncet Sandrine
Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France.
Systems and Synthetic Biology, Chalmers University of Technology, Göteborg, Sweden.
Front Microbiol. 2018 Mar 21;9:486. doi: 10.3389/fmicb.2018.00486. eCollection 2018.
cells can adopt different life-styles in response to various environmental cues, including planktonic cells during vegetative growth, sessile cells during biofilm formation and sporulation. While switching life-styles, bacteria must coordinate the progression of their cell cycle with their physiological status. Our current understanding of the regulatory pathways controlling the decision-making processes and triggering developmental switches highlights a key role of protein phosphorylation. The regulatory mechanisms that integrate the bacterial chromosome replication status with sporulation involve checkpoint proteins that target the replication initiator DnaA or the kinase phosphorelay controlling the master regulator Spo0A. YabA is known to interact with DnaA to prevent over-initiation of replication during vegetative growth. Here, we report that YabA is phosphorylated by YabT, a Ser/Thr kinase expressed during sporulation and biofilm formation. The phosphorylation of YabA has no effect on replication initiation control but hyper-phosphorylation of YabA leads to an increase in sporulation efficiency and a strong inhibition of biofilm formation. We also provide evidence that YabA phosphorylation affects the level of Spo0A-P in cells. These results indicate that YabA is a multifunctional protein with a dual role in regulating replication initiation and life-style switching, thereby providing a potential mechanism for cross-talk and coordination of cellular processes during adaptation to environmental change.
细胞可以根据各种环境线索采取不同的生活方式，包括营养生长期间的浮游细胞、生物膜形成期间的固着细胞和孢子形成。在转换生活方式时，细菌必须使其细胞周期的进程与其生理状态相协调。我们目前对控制决策过程和触发发育转换的调控途径的理解突出了蛋白质磷酸化的关键作用。将细菌染色体复制状态与孢子形成整合在一起的调控机制涉及靶向复制起始因子DnaA或控制主调节因子Spo0A的激酶磷酸化传递的检查点蛋白。已知YabA与DnaA相互作用，以防止营养生长期间复制的过度起始。在这里，我们报告YabA被YabT磷酸化，YabT是一种在孢子形成和生物膜形成期间表达的丝氨酸/苏氨酸激酶。YabA的磷酸化对复制起始控制没有影响，但YabA的过度磷酸化导致孢子形成效率增加和生物膜形成受到强烈抑制。我们还提供证据表明YabA磷酸化影响细胞中Spo0A-P的水平。这些结果表明YabA是一种多功能蛋白，在调节复制起始和生活方式转换中具有双重作用，从而为适应环境变化期间细胞过程的相互作用和协调提供了一种潜在机制。
