C-Abl-mediated Phosphorylation of WAVE3 Is Required for Lamellipodia Formation and Cell Migration

Khalid Sossey-Alaoui,Xiurong Li,John K. Cowell

doi:10.1074/jbc.m701484200

Khalid Sossey-Alaoui, Xiurong Li + Show 1 more

Open Access

https://doi.org/10.1074/jbc.m701484200

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Abstract

The activity of the Wiskott-Aldrich syndrome-related WAVE3 protein is critical for the regulation of the Arp2/3-dependent cytoskeleton organization downstream of Rac-GTPase. The Ableson (Abl) non-receptor tyrosine kinase is also involved in the remolding of actin cytoskeleton in response to extracellular stimuli. Here we show that platelet-derived growth factor stimulation of cultured cells results in WAVE3-Abl interaction and localization to the cell periphery. WAVE3-Abl interaction promotes the tyrosine phosphorylation of WAVE3 by Abl, and STI-571, a specific inhibitor of Abl kinase activity, abrogates the Abl-mediated phosphorylation of WAVE3. We have also shown that Abl targets and phosphorylates four tyrosine residues in WAVE3 and that the Abl-dependent phosphorylation of WAVE3 is critical for the stimulation of lamellipodia formation and cell migration. Our results show that the activation of WAVE3 to promote actin remodeling is enhanced by the c-Abl-mediated tyrosine phosphorylation of WAVE3.

Highlights

Abl Kinase Activity Is Required for WAVE3 Tyrosine Phosphorylation—Our previous study suggested that WAVE3 phosphorylation is required for WAVE3-p85 interaction, and for the PDGF regulation of WAVE3-mediated regulation of lamellipodia formation and cell migration, downstream of phosphatidylinositol 3-kinase [3]
C-Abl tyrosine kinase activity was found to be required for the phosphorylation of WAVE2, a close relative of WAVE3 [30]
Co-immunoprecipitation analyses of protein lysates from PDGF-stimulated MDA-MB-231 cells determined that endogenous WAVE3 and c-Abl proteins are present in the same immunocomplex (Fig. 1B), suggesting that Abl might be involved in WAVE3 phosphorylation

Summary

Introduction

Abl Kinase Activity Is Required for WAVE3 Tyrosine Phosphorylation—Our previous study suggested that WAVE3 phosphorylation is required for WAVE3-p85 interaction, and for the PDGF regulation of WAVE3-mediated regulation of lamellipodia formation and cell migration, downstream of phosphatidylinositol 3-kinase [3]. Immunoblotting with anti-tyrosine antibody of anti-GFP immunoprecipitates of proteins from cells expressing the different WAVE3 mutants shows that WAVE3 is phosphorylated as a full-length protein or when amino acids 91– 440 are present, indicating the presence of target tyrosine residue(s) in this region of the WAVE3 protein (Fig. 4B).

Results

Conclusion