Phosphoinositides containing stearic acid are required for interaction between Rho GTPases and the exocyst to control the late steps of polarized exocytosis.
Patricia Laquel, Eric Testet, Karine Tuphile, Christophe Cullin, Laetitia Fouillen, Jean-Jacques Bessoule, François Doignon
{"title":"Phosphoinositides containing stearic acid are required for interaction between Rho GTPases and the exocyst to control the late steps of polarized exocytosis.","authors":"Patricia Laquel, Eric Testet, Karine Tuphile, Christophe Cullin, Laetitia Fouillen, Jean-Jacques Bessoule, François Doignon","doi":"10.1111/tra.12829","DOIUrl":null,"url":null,"abstract":"<p><p>Cell polarity is achieved by regulators such as small G proteins, exocyst members and phosphoinositides, with the latter playing a key role when bound to the exocyst proteins Sec3p and Exo70p, and Rho GTPases. This ensures asymmetric growth via the routing of proteins and lipids to the cell surface using actin cables. Previously, using a yeast mutant for a lysophosphatidylinositol acyl transferase encoded by the PSI1 gene, we demonstrated the role of stearic acid in the acyl chain of phosphoinositides in cytoskeletal organization and secretion. Here, we use a genetic approach to characterize the effect on late steps of the secretory pathway. The constitutive overexpression of PSI1 in mutants affecting kinases involved in the phosphoinositide pathway demonstrated the role of molecular species containing stearic acid in bypassing a lack of phosphatidylinositol-4-phosphate (PI(4)P) at the plasma membrane, which is essential for the function of the Cdc42p module. Decreasing the levels of stearic acid-containing phosphoinositides modifies the environment of the actors involved in the control of late steps in the secretory pathway. This leads to decreased interactions between Exo70p and Sec3p, with Cdc42p, Rho1p and Rho3p, because of disruption of the GTP/GDP ratio of at least Rho1p and Rho3p GTPases, thereby preventing activation of the exocyst.</p>","PeriodicalId":23207,"journal":{"name":"Traffic","volume":null,"pages":null},"PeriodicalIF":3.6000,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Traffic","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1111/tra.12829","RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2022/1/10 0:00:00","PubModel":"Epub","JCR":"Q3","JCRName":"CELL BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Cell polarity is achieved by regulators such as small G proteins, exocyst members and phosphoinositides, with the latter playing a key role when bound to the exocyst proteins Sec3p and Exo70p, and Rho GTPases. This ensures asymmetric growth via the routing of proteins and lipids to the cell surface using actin cables. Previously, using a yeast mutant for a lysophosphatidylinositol acyl transferase encoded by the PSI1 gene, we demonstrated the role of stearic acid in the acyl chain of phosphoinositides in cytoskeletal organization and secretion. Here, we use a genetic approach to characterize the effect on late steps of the secretory pathway. The constitutive overexpression of PSI1 in mutants affecting kinases involved in the phosphoinositide pathway demonstrated the role of molecular species containing stearic acid in bypassing a lack of phosphatidylinositol-4-phosphate (PI(4)P) at the plasma membrane, which is essential for the function of the Cdc42p module. Decreasing the levels of stearic acid-containing phosphoinositides modifies the environment of the actors involved in the control of late steps in the secretory pathway. This leads to decreased interactions between Exo70p and Sec3p, with Cdc42p, Rho1p and Rho3p, because of disruption of the GTP/GDP ratio of at least Rho1p and Rho3p GTPases, thereby preventing activation of the exocyst.
期刊介绍:
Traffic encourages and facilitates the publication of papers in any field relating to intracellular transport in health and disease. Traffic papers span disciplines such as developmental biology, neuroscience, innate and adaptive immunity, epithelial cell biology, intracellular pathogens and host-pathogen interactions, among others using any eukaryotic model system. Areas of particular interest include protein, nucleic acid and lipid traffic, molecular motors, intracellular pathogens, intracellular proteolysis, nuclear import and export, cytokinesis and the cell cycle, the interface between signaling and trafficking or localization, protein translocation, the cell biology of adaptive an innate immunity, organelle biogenesis, metabolism, cell polarity and organization, and organelle movement.
All aspects of the structural, molecular biology, biochemistry, genetics, morphology, intracellular signaling and relationship to hereditary or infectious diseases will be covered. Manuscripts must provide a clear conceptual or mechanistic advance. The editors will reject papers that require major changes, including addition of significant experimental data or other significant revision.
Traffic will consider manuscripts of any length, but encourages authors to limit their papers to 16 typeset pages or less.