Activation of Cdc42 GTPase upon CRY2-Induced Cortical Recruitment Is Antagonized by GAPs in Fission Yeast

Article Article scientifique Article Activation of Cdc42 GTPase upon CRY2-Induced Cortical Recruitment Is Antagonized by GAPs in Fission Yeast eng 2020-09-12 2020-09-12 author Lamas Iker 0000-0001-6027-0377 author Weber Nathalie 0000-0001-6709-9787 553728 author Martin Sophie 0000-0002-5317-2557 403314 Département de biologie moléculaire et cellulaire (MOCEL) 2089 10.3390/cells9092089 32932721 2073-4409 PMC7565336 https://www.mdpi.com/2073-4409/9/9/2089 <p>The small GTPase Cdc42 is critical for cell polarization in eukaryotic cells. In rod-shaped fission yeast Schizosaccharomyces pombe cells, active GTP-bound Cdc42 promotes polarized growth at cell poles, while inactive Cdc42-GDP localizes ubiquitously also along cell sides. Zones of Cdc42 activity are maintained by positive feedback amplification involving the formation of a complex between Cdc42-GTP, the scaffold Scd2, and the guanine nucleotide exchange factor (GEF) Scd1, which promotes the activation of more Cdc42. Here, we use the CRY2-CIB1 optogenetic system to recruit and cluster a cytosolic Cdc42 variant at the plasma membrane and show that this leads to its moderate activation also on cell sides. Surprisingly, Scd2, which binds Cdc42-GTP, is still recruited to CRY2-Cdc42 clusters at cell sides in individual deletion of the GEFs Scd1 or Gef1. We show that activated Cdc42 clusters at cell sides are able to recruit Scd1, dependent on the scaffold Scd2. However, Cdc42 activity is not amplified by positive feedback and does not lead to morphogenetic changes, due to antagonistic activity of the GTPase activating protein Rga4. Thus, the cell architecture is robust to moderate activation of Cdc42 at cell sides.</p> CRY2-CIBN Cdc42 GTPase activating protein GAP Cell polarity Clustering Fission yeast Schizosaccharomyces pombe Optogenetics Pattern formation Positive feedback European Research Council CellFusion true Cells 9 9 b8c8ba0d-fc86-4487-ad2a-185df0994ce5 Article (Published version) Public Article-scientifique-from-unpaywall.pdf 2552472 application/pdf CC BY-4.0 e3c50346fd262e1e1cc5eb6b6200fd8fdef1ec76a8881b3be46657800bedbfd0 openAccess

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Activation of Cdc42 GTPase upon CRY2-Induced Cortical Recruitment Is Antagonized by GAPs in Fission Yeast	Cells			2020	66	37

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Weber, Nathalie