Related Experiment Video
Updated: Jun 9, 2026
07:59
Temporal Quantification of MAPK Induced Expression in Single Yeast Cells
Published on: October 4, 2013
Stepwise multi-gate control of the HOG MAPK pathway under hyperosmotic stress
Kazuo Tatebayashi1,2, Haruo Saito3
1Laboratory of Molecular Genetics, Frontier Research Unit, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan.
Iscience
|June 8, 2026
Summary
Hyperosmotic stress activates the high-osmolarity glycerol (HOG) pathway in yeast via the SHO1 branch. This study reveals three distinct regulatory steps controlled by stress, ensuring controlled pathway activation.
Area of Science:
- Cellular biology
- Molecular biology
- Biochemistry
Background:
- The high-osmolarity glycerol (HOG) pathway in *Saccharomyces cerevisiae* mediates adaptation to hyperosmotic stress.
- This pathway involves the Hog1 mitogen-activated protein kinase (MAPK) and has two upstream branches: SHO1 and SLN1.
- While transmembrane proteins in the SHO1 branch detect stress, the precise signaling steps remain unclear.
Purpose of the Study:
- To elucidate the specific signaling steps regulated by hyperosmotic stress within the SHO1 branch of the HOG pathway.
- To identify the key proteins and interactions involved in stress-induced activation of the SHO1 branch.
Main Methods:
- Investigated protein interactions and phosphorylation events in response to osmotic stress.
- Utilized genetic and biochemical approaches in *Saccharomyces cerevisiae*.
Main Results:
- Hyperosmotic stress regulates three distinct steps in the SHO1 branch.
- Stress promotes Pbs2 phosphorylation by Ste11 via Sho1-dependent interactions, requiring Hkr1.
- Stress also regulates an upstream step for Ste11 activation, dependent on Hkr1 and Opy2.
Conclusions:
- Osmotic stress exerts multi-gate control over HOG pathway activation.
- The SHO1 branch exhibits stepwise regulation at multiple levels, ensuring precise pathway control.
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