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Nitrogen-dependent calcineurin activation in the yeast Hansenula polymorpha
Celia Rodríguez1, Luis R Galindo, José M Siverio
1Department of Biochemistry and Molecular Biology, Institute of Biomedical Technologies (ITB), Nitrogen Metabolism Group, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Canarias, Spain. celiacrr@ull.es
Fungal Genetics and Biology : FG & B
|February 14, 2013
Summary
Nitrogen sources regulate cell calcium (Ca2+) and activate calcineurin, a key enzyme. Calcineurin controls nitrogen assimilation pathways, impacting gene expression and growth in Hansenula polymorpha.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Nitrogen assimilation is crucial for microbial growth.
- Calcineurin signaling is involved in cellular responses to environmental stimuli.
- The regulation of nitrogen metabolism by calcineurin in yeast is not fully understood.
Purpose of the Study:
- To investigate the role of calcineurin in nitrogen source utilization and assimilation in Hansenula polymorpha.
- To elucidate the molecular mechanisms by which nitrogen availability modulates calcineurin activity.
- To identify key transcription factors regulated by calcineurin in nitrogen metabolism.
Main Methods:
- Analysis of gene expression using quantitative PCR.
- Measurement of intracellular calcium levels.
- Characterization of a calcineurin deletion mutant (cnb1).
- Assessment of transcription factor levels.
Main Results:
- Non-preferred nitrogen sources increased intracellular Ca2+ and ENA1 expression, indicating calcineurin activation.
- Calcineurin (CNB1) is essential for nitrogen catabolite repression (NCR) and nitrate induction.
- Calcineurin regulates NCR via the transcription factors Crz1 and Gat1.
- Calcineurin influences nitrate induction by affecting Gat2 and Yna2 levels.
Conclusions:
- Calcium ions (Ca2+) and calcineurin are central regulators of nitrogen signaling and assimilation.
- Nitrogen availability modulates Ca2+ homeostasis and calcineurin activation.
- Calcineurin acts as a critical link between nitrogen sensing and the regulation of nitrogen assimilation genes.
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