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Yeast respond to hypotonic shock with a calcium pulse
A F Batiza1, T Schulz, P H Masson
1Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
The Journal of Biological Chemistry
|September 20, 1996
Summary
Hypotonic shock triggers a rapid calcium pulse in yeast via stretch-activated channels. Initial calcium influx comes from internal stores, with extracellular calcium sustaining the response.
Area of Science:
- Cell Biology
- Biophysics
- Yeast Physiology
Background:
- Cytosolic calcium ([Ca2+]cyt) plays a crucial role in cellular signaling pathways.
- Understanding calcium dynamics in response to environmental stimuli is vital for cell physiology.
Purpose of the Study:
- To investigate the role of cytosolic calcium in Saccharomyces cerevisiae during hypotonic shock.
- To elucidate the mechanisms and calcium sources involved in the [Ca2+]cyt response to osmotic stress.
Main Methods:
- Utilized a transgenic AEQUORIN calcium reporter system in yeast.
- Applied hypotonic shock and monitored real-time [Ca2+]cyt changes.
- Investigated the effects of gadolinium (stretch-activated channel blocker) and BAPTA (extracellular calcium chelator).
Main Results:
- Hypotonic shock induced a rapid, transient rise in [Ca2+]cyt.
- Gadolinium abolished this calcium rise, indicating involvement of stretch-activated channels.
- The initial calcium rise was insensitive to extracellular BAPTA, but sustained elevation was attenuated.
- These findings suggest a dual calcium source: intracellular stores for the initial pulse and extracellular calcium for sustained response.
Conclusions:
- Hypotonic shock in yeast generates a calcium pulse dependent on stretch-activated channels.
- The immediate calcium influx originates from intracellular stores.
- Sustained cytosolic calcium increase relies on extracellular calcium influx.