This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wang, L.-y. Articles by Shiozaki, K. Search for Related Content PubMed PubMed Citation Articles by Wang, L.-y. Articles by Shiozaki, K.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, May 2005, p. 3945-3955, Vol. 25, No. 10
0270-7306/05/$08.00+0     doi:10.1128/MCB.25.10.3945-3955.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Response of Fission Yeast to Toxic Cations Involves Cooperative Action of the Stress-Activated Protein Kinase Spc1/Sty1 and the Hal4 Protein Kinase

Ling-yu Wang, Koichi Shimada, Masayo Morishita, and Kazuhiro Shiozaki^*

Section of Microbiology, Division of Biological Sciences, University of California, Davis, California 95616

Received 13 December 2004/ Returned for modification 19 January 2005/ Accepted 22 February 2005

Stress-activated protein kinases (SAPKs), members of a mitogen-activated protein kinase (MAPK) subfamily, are highly conserved among eukaryotes. Studies of yeasts demonstrated that SAPKs play pivotal roles in survival responses to high osmolarity, oxidative stress, and heat shock. Here we report a novel physiological role of the fission yeast Spc1 SAPK in cellular resistance to certain cations, such as Na⁺, Li⁺, and Ca²⁺. Strains lacking Spc1 or its activator, Wis1 MAPK kinase, are hypersensitive to these cations. Spc1 positively regulates expression of sod2⁺ encoding a Na⁺/H⁺ antiporter through Atf1 and other transcription factors. In addition, we have identified a novel Spc1-interacting protein, Hal4, which is highly homologous to the budding yeast Sat4/Hal4 protein kinase. Like its budding yeast counterpart, the fission yeast Hal4 kinase is essential for cellular resistance to Na⁺, Li⁺, and Ca²⁺. The hal4-null phenotype is complemented by overexpression of the Trk1 potassium transporter or increased K⁺ in the growth medium, suggesting that Hal4 promotes K⁺ uptake, which consequently increases cellular resistance to other cations. Interestingly, the Spc1-Hal4 interaction appears to be required for cellular resistance to Ca²⁺ but not Na⁺ and Li⁺. We propose that Spc1 SAPK and Hal4 kinase cooperatively function to protect cells from the toxic cations.

---

* Corresponding author. Mailing address: Section of Microbiology, Division of Biological Sciences, University of California, Davis, CA 95616. Phone: (530) 752-3628. Fax: (530) 752-9014. E-mail: kshiozaki{at}ucdavis.edu.

Present address: Department of Periodontology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo 101-8310, Japan.

---

Molecular and Cellular Biology, May 2005, p. 3945-3955, Vol. 25, No. 10
0022-538X/05/$08.00+0     doi:10.1128/MCB.25.10.3945-3955.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Perez-Valle, J., Jenkins, H., Merchan, S., Montiel, V., Ramos, J., Sharma, S., Serrano, R., Yenush, L. (2007). Key Role for Intracellular K+ and Protein Kinases Sat4/Hal4 and Hal5 in the Plasma Membrane Stabilization of Yeast Nutrient Transporters. Mol. Cell. Biol. 27: 5725-5736 [Abstract] [Full Text]  
• Thornton, G., Wilkinson, C. R. M., Toone, W. M., Jones, N. (2005). A novel pathway determining multidrug sensitivity in Schizosaccharomyces pombe. GENES CELLS 10: 941-951 [Abstract] [Full Text]