Coupled excitable Ras and F-actin activation mediates spontaneous pseudopod formation and directed cell movement.

ABSTRACT: Many eukaryotic cells regulate their mobility by external cues. Genetic studies have identified >100 components that participate in chemotaxis, which hinders the identification of the conceptual framework of how cells sense and respond to shallow chemical gradients. The activation of Ras occurs during basal locomotion and is an essential connector between receptor and cytoskeleton during chemotaxis. Using a sensitive assay for activated Ras, we show here that activation of Ras and F-actin forms two excitable systems that are coupled through mutual positive feedback and memory. This coupled excitable system leads to short-lived patches of activated Ras and associated F-actin that precede the extension of protrusions. In buffer, excitability starts frequently with Ras activation in the back/

SUBMITTER: van Haastert PJ 

PROVIDER: S-EPMC5385941 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature