Related Experiment Videos
Ca2+ transport in Saccharomyces cerevisiae
1Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, 9 Cambridge Center 02142.
The Journal of Experimental Biology
|November 1, 1994
Summary
Budding yeast uses Ca2+ pumps (PMC1, PMR1) for calcium regulation. Deleting both is lethal, activating calcineurin, which impacts calcium transport and tolerance.
Area of Science:
- Cellular biology
- Molecular biology
- Biochemistry
Background:
- Cytosolic free Ca2+ is tightly regulated in budding yeast via pumps and antiporters.
- PMC1 and PMR1 are identified as key Ca2+ pumps for vacuolar and secretory organelle sequestration.
- Dual deletion of PMC1 and PMR1 leads to lethality due to elevated cytosolic Ca2+.
Purpose of the Study:
- To investigate the roles of Ca2+ pumps PMC1 and PMR1 in yeast calcium homeostasis.
- To elucidate the mechanism by which calcineurin activation affects Ca2+ transport.
- To model the cellular response to environmental calcium fluctuations.
Main Methods:
- Gene deletion studies to assess the impact of PMC1 and PMR1 on yeast viability.
- Analysis of cytosolic Ca2+ levels in response to pump activity.
- Investigation of calcineurin's role in regulating Ca2+ transporters.
Main Results:
- The function of either PMC1 or PMR1 alone is sufficient for yeast viability.
- Deletion of both PMC1 and PMR1 is lethal, causing increased cytosolic Ca2+ and calcineurin activation.
- Calcineurin activation influences vacuolar Ca2+ sequestration and potentially Ca2+ pump activity.
Conclusions:
- Calcineurin and calmodulin mediate the cellular response to environmental Ca2+ levels.
- These regulatory pathways modulate various Ca2+ transporters, impacting yeast Ca2+ tolerance.
- A model is proposed where calmodulin and calcineurin integrate Ca2+ signals to control transporter activity.