Adaptor protein Ste50p links the Ste11p MEKK to the HOG pathway through plasma membrane association
- 1 Genetics Group, Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec, Canada H4P 2R2;
- 2 Department of Biochemistry, McGill University, Montreal, Quebec, Canada H3G 1Y6;
- 3 Department of Biology, McGill University, Montreal, Quebec, Canada H3A 1B1
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↵4 These authors contributed equally to this work.
Abstract
In a variety of yeast cellular pathways, the Ste50p protein regulates the kinase function of the mitogen extracellular signal-regulated kinase kinase (MEKK) Ste11p. Both Ste11p and Ste50p contain sterile α motif (SAM) domains; these are interchangeable, and can be replaced by other protein-interacting modules. Furthermore, the function of the Ras association (RA)-like domain of Ste50p can be mimicked by a plasma membrane recruiting signal, and direct plasma membrane targeting of Ste11p bypasses the requirement of Ste50p for Ste11p function. Thus the regulatory role of Ste50p requires both the N-terminal SAM domain to bind Ste11p and the C-terminal RA-like domain to direct kinase localization. We have identified Opy2p, an integral membrane protein that can interact with Ste50p, as a new component in the Sho1p–Ste11p/Ste50p signaling branch of the high-osmolarity glycerol (HOG) pathway. We propose that Opy2p can serve as a membrane anchor for the Ste50p/Ste11p module in the activation of the HOG pathway.
Keywords
Footnotes
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↵5 Corresponding author.
↵5 E-MAIL cunle.wu@cnrc-nrc.gc.ca; FAX (514) 496-6213.
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Article and publication are at http://www.genesdev.org/cgi/doi/10.1101/gad.1375706
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- Received September 19, 2005.
- Accepted January 23, 2006.
- Copyright © 2006, Cold Spring Harbor Laboratory Press