1. The Ste5 Scaffold Allosterically Modulates Signaling Output of the Yeast Mating Pathway.
- Author
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Bhattacharyya, Roby P., Reményi, Attila, Good, Matthew C., Bashor, Caleb J., Falick, Arnold M., and Lim, Wendell A.
- Subjects
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PROTEIN kinases , *CHEMICAL reactions , *BIOCHEMISTRY , *PHOSPHORYLATION , *PHOSPHORYLASES , *PROTEINS , *MITOGENS , *YEAST , *RESEARCH - Abstract
Scaffold proteins organize signaling proteins into pathways and are often viewed as passive assembly platforms. We found that the Ste5 scaffold has a more active role in the yeast mating pathway: A fragment of Ste5 allosterically activated autophosphorylation of the mitogen-activated protein kinase Fus3. The resulting form of Fus3 is partially active — it is phosphorylated on only one of two key residues in the activation loop. Unexpectedly, at a systems level, autoactivated Fus3 appears to have a negative regulatory role, promoting Ste5 phosphorylation and a decrease in pathway transcriptional output. Thus, scaffolds not only direct basic pathway connectivity but can precisely tune quantitative pathway input-output properties. [ABSTRACT FROM AUTHOR]
- Published
- 2006
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