TOR complex 1 negatively regulates NDR kinase Cbk1 to control cell separation in budding yeast
Magdalena Foltman1,2, Iván Mendez2,3, Joan J Bech-Serra4
1Mechanisms and Regulation of Cell Division Research Unit, Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, Santander, Spain.
Plos Biology
|August 30, 2023
Summary
Target of rapamycin complex 1 (TORC1) in yeast blocks cell separation after division. It achieves this by phosphorylating the Cbk1 protein kinase, impacting cell cycle progression and membrane fusion.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- The target of rapamycin (TOR) pathway is crucial for coordinating cell growth and the cell cycle.
- Mechanisms by which TOR regulates post-anaphase events, including cell separation, are not fully understood.
Purpose of the Study:
- To elucidate the molecular mechanisms by which TOR signaling regulates cell separation in budding yeast.
- To identify key proteins and phosphorylation events involved in TOR-mediated control of cytokinesis.
Main Methods:
- Investigated the role of TOR complex 1 (TORC1) in budding yeast cell separation.
- Utilized phosphomimetic substitution to analyze Cbk1 kinase activity.
- Identified Sec3 as a substrate of Cbk1 and examined its interaction with SNARE components.
Main Results:
- TORC1 was found to inhibit cell separation by phosphorylating the NDR kinase Cbk1.
- Phosphorylation at residue T574 of Cbk1 was identified as critical for TORC1's control over cell separation.
- TORC1 activity was shown to disrupt the interaction between Sec3 and t-SNARE, hindering membrane fusion.
Conclusions:
- TORC1 negatively regulates cell separation in budding yeast through Cbk1 phosphorylation.
- This pathway controls the fusion of secretory vesicles at the division site, impacting cytokinesis completion.
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