We have investigated the conditions required for polar localization of the CheZ phosphatase by using a CheZ-green fluorescent protein fusion protein that, when expressed from a single gene in the chromosome, restored chemotaxis to a DeltacheZ strain. Localization was observed in wild-type, DeltacheZ, DeltacheYZ, and DeltacheRB cells but not in cells with cheA, cheW, or all chemoreceptor genes except aer deleted. Cells making only CheA-short (CheA(S)) or CheA lacking the P2 domain also retained normal localization, whereas cells producing only CheA-long or CheA missing the P1 and P2 domains did not. We conclude that CheZ localization requires the truncated C-terminal portion of the P1 domain present in CheA(S). Missense mutations targeting residues 83 through 120 of CheZ also abolished localization. Two of these mutations do not disrupt chemotaxis, indicating that they specifically prevent interaction with CheA(S) while leaving other activities of CheZ intact.
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http://dx.doi.org/10.1128/JB.185.7.2354-2361.2003 | DOI Listing |
Mol Microbiol
October 2024
Department of Biological Sciences, Life Sciences I, Virginia Tech, Blacksburg, Virginia, USA.
Sinorhizobium meliloti senses nutrients and compounds exuded from alfalfa host roots and coordinates an excitation, termination, and adaptation pathway during chemotaxis. We investigated the role of the novel S. meliloti chemotaxis protein CheT.
View Article and Find Full Text PDFJ Invertebr Pathol
March 2024
The Laboratory of Aquatic Parasitology, School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong 266237, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China. Electronic address:
Ameson portunus, the recently discovered causative agent of "toothpaste disease" of pond-cultured swimming crabs in China has caused enormous economic losses in aquaculture. Understanding the process of spore germination is helpful to elucidate the molecular mechanism of its invasion of host cells. Here, we obtained mature and germinating spores by isolation and purification and in vitro stimulation, respectively.
View Article and Find Full Text PDFBiophys J
January 2022
Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, China. Electronic address:
In bacterial chemotaxis, the output of chemosensing, the concentration of the response regulator CheY-P that was constantly adjusted by the opposing action of the kinase CheA and the phosphatase CheZ, serves as the input of the ultrasensitive flagellar motor that drives bacterial motility. The steady-state kinase activity exhibits large cell-to-cell variation that may result in similar variation in CheY-P concentration. Here, we found that the in vivo phosphatase activity is highly cooperative with respect to CheY-P concentration, and this suppresses the cell-to-cell variation of CheY-P concentration so that it falls within the operational range of the flagellar motor.
View Article and Find Full Text PDFJ Bacteriol
February 2022
Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA.
Azorhizobium caulinodans is a nitrogen-fixing bacterium that forms root nodules on its host legume, Sesbania rostrata. This agriculturally significant symbiotic relationship is important in lowland rice cultivation and allows nitrogen fixation under flood conditions. Chemotaxis plays an important role in bacterial colonization of the rhizosphere.
View Article and Find Full Text PDFFront Microbiol
October 2021
National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment of Shandong Agricultural University, Taian, China.
Spatial organization of chemotactic proteins is important for cooperative response to external stimuli. However, factors affecting the localization dynamics of chemotaxis proteins are less studied. According to some reports, the polar localization of chemotaxis system I is induced by hypoxia and starvation in .
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