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Conserved Ark1-related kinases function in a TORC2 signaling network.
Maria Alcaide-Gavilán1, Rafael Lucena1, Selene Banuelos1
1Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064.
Molecular Biology of the Cell
|July 3, 2020
Summary
Researchers identified Ark1 and Prk1 kinases in the target of rapamycin complex 2 (TORC2) network, revealing their role in controlling cell growth and size. This discovery highlights how TORC2 signaling coordinates cell growth and endocytosis for size homeostasis.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Cell cycle progression relies on cell growth, with rapid growth in rich nutrients leading to larger cell sizes.
- The target of rapamycin complex 2 (TORC2) network in budding yeast regulates growth rate and cell size based on nutrient availability.
Purpose of the Study:
- To identify new components of the TORC2 network.
- To investigate the role of identified kinases, Ark1 and Prk1, within the TORC2 network and their influence on cell size homeostasis.
Main Methods:
- Screening for novel TORC2 network components.
- Investigating the function of Ark1 and Prk1 in budding yeast.
- Analyzing the relationship between endocytosis and cell size.
Main Results:
- Identified Ark1 and Prk1 as redundant kinase paralogues embedded in the TORC2 network.
- Demonstrated that Ark/Prk influence TORC2 signaling independently of their known endocytic roles.
- Showed that reduced endocytosis results in increased cell size, indicating a link between endocytosis and cell size control.
Conclusions:
- Ark1 and Prk1 are integral components of the TORC2 network, impacting cell growth and size.
- Cell size homeostasis requires coordinated regulation of plasma membrane growth and endocytosis.
- A model is proposed where TORC2-dependent signals balance plasma membrane growth and endocytosis to maintain appropriate cell size according to nutrient availability.
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