This Article Full Text Full Text (PDF) Supplemental material 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 Maleri, S. Articles by Errede, B. Search for Related Content PubMed PubMed Citation Articles by Maleri, S. Articles by Errede, B.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, October 2004, p. 9221-9238, Vol. 24, No. 20
0270-7306/04/$08.00+0     DOI: 10.1128/MCB.24.20.9221-9238.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

Persistent Activation by Constitutive Ste7 Promotes Kss1-Mediated Invasive Growth but Fails To Support Fus3-Dependent Mating in Yeast

Seth Maleri, Qingyuan Ge, Elizabeth A. Hackett, Yuqi Wang, Henrik G. Dohlman, and Beverly Errede^*

Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina

Received 22 October 2003/ Returned for modification 1 December 2003/ Accepted 26 July 2004

Mitogen-activated protein kinase kinase kinase-Ste11 (MAPKKK-Ste11), MAPKK-Ste7, and MAPK-Kss1 mediate pheromone-induced mating differentiation and nutrient-responsive invasive growth in Saccharomyces cerevisiae. The mating pathway also requires the scaffold-Ste5 and the additional MAPK-Fus3. One contribution to specificity in this system is thought to come from stimulus-dependent recruitment of the MAPK cascade to upstream activators that are unique to one or the other pathway. To test this premise, we asked if stimulus-independent signaling by constitutive Ste7 would lead to a loss of biological specificity. Instead, we found that constitutive Ste7 promotes invasion without supporting mating responses. This specificity occurs because constitutive Ste7 activates Kss1, but not Fus3, in vivo and promotes filamentation gene expression while suppressing mating gene expression. Differences in the ability of constitutive Ste7 variants to bind the MAPKs and Ste5 account for the selective activation of Kss1. These findings support the model that Fus3 activation in vivo requires binding to both Ste7 and the scaffold-Ste5 but that Kss1 activation is independent of Ste5. This scaffold-independent activation of Kss1 by constitutive Ste7 and the existence of mechanisms for pathway-specific promoter discrimination impose a unique developmental fate independently of any distinguishing external stimuli.

---

* Corresponding author. Mailing address: Department of Biochemistry and Biophysics, CB 7260, 512 ME Jones, University of North Carolina, Chapel Hill, NC 27599-7260. Phone: (919) 966-3628. Fax: (919) 966-4812. E-mail: errede{at}email.unc.edu.

Supplemental material for this article may be found at http://mcb.asm.org/.

Present address: Cell Signaling Technology, Inc., Beverly, MA 01915.

---

Molecular and Cellular Biology, October 2004, p. 9221-9238, Vol. 24, No. 20
0022-538X/04/$08.00+0     DOI: 10.1128/MCB.24.20.9221-9238.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Hao, N., Zeng, Y., Elston, T. C., Dohlman, H. G. (2008). Control of MAPK Specificity by Feedback Phosphorylation of Shared Adaptor Protein Ste50. J. Biol. Chem. 283: 33798-33802 [Abstract] [Full Text]  
• Jimenez-Sanchez, M., Cid, V. J., Molina, M. (2007). Retrophosphorylation of Mkk1 and Mkk2 MAPKKs by the Slt2 MAPK in the Yeast Cell Integrity Pathway. J. Biol. Chem. 282: 31174-31185 [Abstract] [Full Text]  
• Westfall, P. J., Thorner, J. (2006). Analysis of Mitogen-Activated Protein Kinase Signaling Specificity in Response to Hyperosmotic Stress: Use of an Analog-Sensitive HOG1 Allele.. Eukaryot Cell 5: 1215-1228 [Abstract] [Full Text]  
• Flatauer, L. J., Zadeh, S. F., Bardwell, L. (2005). Mitogen-Activated Protein Kinases with Distinct Requirements for Ste5 Scaffolding Influence Signaling Specificity in Saccharomyces cerevisiae. Mol. Cell. Biol. 25: 1793-1803 [Abstract] [Full Text]