This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kawano, M.
Right arrow Articles by Kakinuma, Y.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kawano, M.
Right arrow Articles by Kakinuma, Y.

 Previous Article  |  Next Article 

Journal of Bacteriology, May 2000, p. 2507-2512, Vol. 182, No. 9
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.

Evidence for Na+ Influx via the NtpJ Protein of the KtrII K+ Uptake System in Enterococcus hirae

Miyuki Kawano, Ryoko Abuki, Kazuei Igarashi, and Yoshimi Kakinuma*

Faculty of Pharmaceutical Sciences, Chiba University, Inage-ku, Chiba 263-8522, Japan

Received 23 November 1999/Accepted 15 February 2000

The ntpJ gene, a cistron located at the tail end of the vacuolar-type Na+-ATPase (ntp) operon of Enterococcus hirae, encodes a transporter of the KtrII K+ uptake system. We found that K+ accumulation in the ntpJ-disrupted mutant JEM2 was markedly enhanced by addition of valinomycin at pH 10. Studies of the membrane potential (Delta Psi ; inside negative) by 3,3'-dihexyloxacarbocyanine iodide fluorescence revealed that the Delta Psi was hyperpolarized at pH 10 in JEM2; the Delta Psi values of the parent strain ATCC 9790 and JEM2, estimated by determining the equilibrium distribution of K+ or Rb+ in the presence of valinomycin, were -118 and -160 mV, respectively. Delta Psi generation at pH 10 was accomplished by an electrogenic Na+ efflux via the Na+-ATPase, whose levels in the two strains were quite similar. Na+ uptake driven by an artificially imposed Delta Psi (inside negative) was missing in JEM2, suggesting that NtpJ mediates Na+ movement in addition to K+ movement. Finally, the growth of JEM2 arrested in K+-limited high-Na+ medium at pH 10 was restored by addition of valinomycin. These results suggest that NtpJ mediates electrogenic transport of K+ as well as Na+, that it likely mediates K+ and Na+ cotransport, and that Na+ movement via NtpJ is the major Na+ reentry pathway at high pH values.

* Corresponding author. Mailing address: Faculty of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan. Phone: 81-43-290-2898. Fax: 81-43-290-2900. E-mail: yoshimi{at}p.chiba-u.ac.jp.

Journal of Bacteriology, May 2000, p. 2507-2512, Vol. 182, No. 9
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:

  • Horie, T., Horie, R., Chan, W.-Y., Leung, H.-Y., Schroeder, J. I. (2006). Calcium Regulation of Sodium Hypersensitivities of sos3 and athkt1 Mutants. Plant Cell Physiol 47: 622-633 [Abstract] [Full Text]  
  • Tholema, N., Bruggen, M. V. d., Maser, P., Nakamura, T., Schroeder, J. I., Kobayashi, H., Uozumi, N., Bakker, E. P. (2005). All Four Putative Selectivity Filter Glycine Residues in KtrB Are Essential for High Affinity and Selective K+ Uptake by the KtrAB System from Vibrio alginolyticus. J. Biol. Chem. 280: 41146-41154 [Abstract] [Full Text]  
  • Matsuda, N., Kobayashi, H., Katoh, H., Ogawa, T., Futatsugi, L., Nakamura, T., Bakker, E. P., Uozumi, N. (2004). Na+-dependent K+ Uptake Ktr System from the Cyanobacterium Synechocystis sp. PCC 6803 and Its Role in the Early Phases of Cell Adaptation to Hyperosmotic Shock. J. Biol. Chem. 279: 54952-54962 [Abstract] [Full Text]  
  • Gardan, R., Cossart, P., The European Listeria Genome Consortium,, , Labadie, J. (2003). Identification of Listeria monocytogenes Genes Involved in Salt and Alkaline-pH Tolerance. Appl. Environ. Microbiol. 69: 3137-3143 [Abstract] [Full Text]  
  • Maser, P., Hosoo, Y., Goshima, S., Horie, T., Eckelman, B., Yamada, K., Yoshida, K., Bakker, E. P., Shinmyo, A., Oiki, S., Schroeder, J. I., Uozumi, N. (2002). Glycine residues in potassium channel-like selectivity filters determine potassium selectivity in four-loop-per-subunit HKT transporters from plants. Proc. Natl. Acad. Sci. USA 99: 6428-6433 [Abstract] [Full Text]  
  • Uozumi, N. (2001). Escherichia coli as an expression system for K+ transport systems from plants. Am. J. Physiol. Cell Physiol. 281: C733-C739 [Abstract] [Full Text]  
  • Maser, P., Hosoo, Y., Goshima, S., Horie, T., Eckelman, B., Yamada, K., Yoshida, K., Bakker, E. P., Shinmyo, A., Oiki, S., Schroeder, J. I., Uozumi, N. (2002). Glycine residues in potassium channel-like selectivity filters determine potassium selectivity in four-loop-per-subunit HKT transporters from plants. Proc. Natl. Acad. Sci. USA 99: 6428-6433 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»