An adenylyl cyclase, CyaB, acts as an osmosensor in Myxococcus xanthus.
We have previously reported that a receptor-type adenylyl cyclase (CyaA) of Myxococcus xanthus undergoes an osmosensor mainly during spore germination (Y. Kimura et al., J. Bacteriol. 184:3578-3585, 2002). In the present study, we cloned another receptor-type adenylyl cyclase gene (cyaB) and characterized the function of the cyaB-encoded protein. Disruption of cyaB generates a mutant that showed growth retardation at high ionic (NaCl) or high nonionic (sucrose) osmolarity. When vegetative cells were stimulated with 0.15 M NaCl, the increases in intracellular cyclic AMP levels of cyaB mutant cells were lower than those of wild-type cells. Under nonionic osmostress, the cyaB mutant exhibited reduced spore germination; however, the germination rate of the cyaB mutant was significantly higher than that of the cyaA mutant.
Kimura
Yoshio
Y
Department of Life Sciences, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa, Japan 761-0795. kimura@ag.kagawa-u.ac.jp
Ohtani
Mika
M
Takegawa
Kaoru
K
D000262:Adenylyl Cyclases / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D000242:Cyclic AMP; D008969:Molecular Sequence Data; D016941:Myxococcus xanthus / Q000201:enzymology* / Q000235:genetics*; D009997:Osmotic Pressure; D015398:Signal Transduction / Q000502:physiology; D014882:Water-Electrolyte Balance / Q000502:physiology*
D000242:Cyclic AMP; D000262:Adenylyl Cyclases