Mutually inhibitory Ras-PI(3,4)P2 feedback loops mediate cell migration

Xiaoguang Li, Marc Edwards, Kristen F. Swaney, Nilmani Singh, Sayak Bhattacharya, Jane Borleis, Yu Long, Pablo A. Iglesias, Jie Chen, Peter N. Devreotes

Research output: Contribution to journalArticlepeer-review

Abstract

Signal transduction and cytoskeleton networks in a wide variety of cells display excitability, but the mechanisms are poorly understood. Here, we show that during random migration and in response to chemoattractants, cells maintain complementary spatial and temporal distributions of Ras activity and phosphatidylinositol (3,4)-bisphosphate [PI(3,4)P2]. In addition, depletion of PI(3,4)P2 by disruption of the 5-phosphatase, Dd5P4, or by recruitment of 4-phosphatase INPP4B to the plasma membrane, leads to elevated Ras activity, cell spreading, and altered migratory behavior. Furthermore, RasGAP2 and RapGAP3 bind to PI(3,4)P2, and the phenotypes of cells lacking these genes mimic those with low PI(3,4)P2 levels, providing amolecular mechanism. These findings suggest that Ras activity drives PI(3,4)P2 down, causing the PI(3,4)P2- binding GAPs to dissociate from the membrane, further activating Ras, completing a positive-feedback loop essential for excitability. Consistently, a computational model incorporating such a feedback loop in an excitable network model accurately simulates the dynamic distributions of active Ras and PI(3,4)P2 as well as cell migratory behavior. The mutually inhibitory Ras-PI(3,4)P2 mechanisms we uncovered here provide a framework for Ras regulation that may play a key role in many physiological processes.

Original languageEnglish (US)
Pages (from-to)E9125-E9134
JournalProceedings of the National Academy of Sciences of the United States of America
Volume115
Issue number39
DOIs
StatePublished - Sep 25 2018

Keywords

  • Chemotaxis
  • Excitability
  • Phosphoinositides
  • Positive feedback loop
  • Signal transduction

ASJC Scopus subject areas

  • General

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