Katsushi Yamaguchi

Publications (2)18.67 Total impact

• Source

  Available from: Norio Murata

  Article: Identification of histidine kinases that act as sensors in the perception of salt stress in Synechocystis sp. PCC 6803.

  Kay Marin, Iwane Suzuki, Katsushi Yamaguchi, Kathrin Ribbeck, Hiroshi Yamamoto, Yu Kanesaki, Martin Hagemann, Norio Murata
  [show abstract] [hide abstract]
  ABSTRACT: In plants and microorganisms, salt stress regulates the expression of large numbers of genes. However, the machinery that senses salt stress remains to be characterized. In this study we identified sensory histidine kinases that are involved in the perception of salt stress in the cyanobacterium Synechocystis sp. strain PCC 6803. A library of strains with mutations in all 43 histidine kinases was screened by DNA microarray analysis of genomewide gene expression under salt stress. The results suggested that four histidine kinases, namely, Hik16, Hik33, Hik34, and Hik41, perceived and transduced salt signals. However, Hik33, Hik34, and Hik16 acting with Hik41 regulated the expression of different sets of genes. These histidine kinases regulated the expression of approximately 20% of the salt-inducible genes, whereas the induction of the remaining salt-inducible genes was unaffected by mutations in any of the histidine kinases, suggesting that additional sensory mechanisms might operate in the perception of salt stress. We also used DNA microarrays to investigate the effect of various salts on gene expression. Our results indicate that Hik33 responds to sodium salts and not to KCl, whereas the Hik16/Hik41 system responds only to NaCl.
  Proceedings of the National Academy of Sciences 08/2003; 100(15):9061-6. · 9.68 Impact Factor
• Source

  Available from: Norio Murata

  Article: A two-component Mn2+-sensing system negatively regulates expression of the mntCAB operon in Synechocystis.

  Katsushi Yamaguchi, Iwane Suzuki, Hiroshi Yamamoto, Alexander Lyukevich, Irina Bodrova, Dmitry A Los, Irina Piven, Vladislav Zinchenko, Minoru Kanehisa, Norio Murata
  [show abstract] [hide abstract]
  ABSTRACT: Mn is an essential component of the oxygen-evolving machinery of photosynthesis and is an essential cofactor of several important enzymes, such as Mn-superoxide dismutase and Mn-catalase. The availability of Mn in the environment varies, and little is known about the mechanisms for maintaining cytoplasmic Mn(2+) ion homeostasis. Using a DNA microarray, we screened knockout libraries of His kinases and response regulators of Synechocystis sp PCC 6803 to identify possible participants in this process. We identified a His kinase, ManS, which might sense the extracellular concentration of Mn(2+) ions, and a response regulator, ManR, which might regulate the expression of the mntCAB operon for the ABC-type transporter of Mn(2+) ions. Furthermore, analysis with the DNA microarray and by reverse transcription PCR suggested that ManS produces a signal that activates ManR, which represses the expression of the mntCAB operon. At low concentrations of Mn(2+) ions, ManS does not generate a signal, with resulting inactivation of ManR and subsequent expression of the mntCAB operon.
  The Plant Cell 12/2002; 14(11):2901-13. · 8.99 Impact Factor