Cell–substrate adhesion drives Scar/WAVE activation and phosphorylation by a Ste20-family kinase, which controls pseudopod lifetime
Open Access
- 3 August 2020
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLoS Biology
- Vol. 18 (8), e3000774
- https://doi.org/10.1371/journal.pbio.3000774
Abstract
The Scar/WAVE complex is the principal catalyst of pseudopod and lamellipod formation. Here we show that Scar/WAVE’s proline-rich domain is polyphosphorylated after the complex is activated. Blocking Scar/WAVE activation stops phosphorylation in both Dictyostelium and mammalian cells, implying that phosphorylation modulates pseudopods after they have been formed, rather than controlling whether they are initiated. Unexpectedly, phosphorylation is not promoted by chemotactic signaling but is greatly stimulated by cell:substrate adhesion and diminished when cells deadhere. Phosphorylation-deficient or phosphomimetic Scar/WAVE mutants are both normally functional and rescue the phenotype of knockout cells, demonstrating that phosphorylation is dispensable for activation and actin regulation. However, pseudopods and patches of phosphorylation-deficient Scar/WAVE last substantially longer in mutants, altering the dynamics and size of pseudopods and lamellipods and thus changing migration speed. Scar/WAVE phosphorylation does not require ERK2 in Dictyostelium or mammalian cells. However, the MAPKKK homologue SepA contributes substantially—sepA mutants have less steady-state phosphorylation, which does not increase in response to adhesion. The mutants also behave similarly to cells expressing phosphorylation-deficient Scar, with longer-lived pseudopods and patches of Scar recruitment. We conclude that pseudopod engagement with substratum is more important than extracellular signals at regulating Scar/WAVE’s activity and that phosphorylation acts as a pseudopod timer by promoting Scar/WAVE turnover.Funding Information
- Cancer Research UK (A17196)
- Cancer Research UK (A20017)
This publication has 65 references indexed in Scilit:
- WAVE regulatory complex activation by cooperating GTPases Arf and Rac1Proceedings of the National Academy of Sciences of the United States of America, 2011
- ERK-MAPK Drives Lamellipodia Protrusion by Activating the WAVE2 Regulatory ComplexMolecular Cell, 2011
- Activation of the WAVE Complex by Coincident Signals Controls Actin AssemblyMolecular Cell, 2009
- Coordination of Rho GTPase activities during cell protrusionNature, 2009
- A new set of small, extrachromosomal expression vectors for Dictyostelium discoideumPlasmid, 2009
- Neutrophils Establish Rapid and Robust WAVE Complex Polarity in an Actin-Dependent FashionCurrent Biology, 2009
- WAVE2 is regulated by multiple phosphorylation events within its VCA domainCell Motility, 2009
- MaxQuant enables high peptide identification rates, individualized p.p.b.-range mass accuracies and proteome-wide protein quantificationNature Biotechnology, 2008
- Chemotaxis in shallow gradients is mediated independently of PtdIns 3-kinase by biased choices between random protrusionsNature, 2007
- Empirical Statistical Model To Estimate the Accuracy of Peptide Identifications Made by MS/MS and Database SearchAnalytical Chemistry, 2002