Dyrk1A negatively regulates the actin cytoskeleton through threonine phosphorylation of N-WASP

J Cell Sci. 2012 Jan 1;125(Pt 1):67-80. doi: 10.1242/jcs.086124. Epub 2012 Jan 16.

Abstract

Neural Wiskott-Aldrich syndrome protein (N-WASP) is involved in tight regulation of actin polymerization and dynamics. N-WASP activity is regulated by intramolecular interaction, binding to small GTPases and tyrosine phosphorylation. Here, we report on a novel regulatory mechanism; we demonstrate that N-WASP interacts with dual-specificity tyrosine-phosphorylation-regulated kinase 1A (Dyrk1A). In vitro kinase assays indicate that Dyrk1A directly phosphorylates the GTPase-binding domain (GBD) of N-WASP at three sites (Thr196, Thr202 and Thr259). Phosphorylation of the GBD by Dyrk1A promotes the intramolecular interaction of the GBD and verprolin, cofilin and acidic (VCA) domains of N-WASP, and subsequently inhibits Arp2/3-complex-mediated actin polymerization. Overexpression of either Dyrk1A or a phospho-mimetic N-WASP mutant inhibits filopodia formation in COS-7 cells. By contrast, the knockdown of Dyrk1A expression or overexpression of a phospho-deficient N-WASP mutant promotes filopodia formation. Furthermore, the overexpression of a phospho-mimetic N-WASP mutant significantly inhibits dendritic spine formation in primary hippocampal neurons. These findings suggest that Dyrk1A negatively regulates actin filament assembly by phosphorylating N-WASP, which ultimately promotes the intramolecular interaction of its GBD and VCA domains. These results provide insight on the mechanisms contributing to diverse actin-based cellular processes such as cell migration, endocytosis and neuronal differentiation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / metabolism*
  • Actin-Related Protein 2-3 Complex / metabolism
  • Actins / chemistry
  • Actins / metabolism*
  • Animals
  • COS Cells
  • Chlorocebus aethiops
  • Dendrites / metabolism
  • GTP Phosphohydrolases / metabolism
  • Gene Expression
  • Humans
  • Mice
  • Molecular Sequence Data
  • Phosphorylation
  • Phosphothreonine / metabolism*
  • Protein Binding
  • Protein Structure, Tertiary
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • Protein-Tyrosine Kinases / genetics
  • Protein-Tyrosine Kinases / metabolism*
  • Pseudopodia / metabolism
  • Rats
  • Wiskott-Aldrich Syndrome Protein / antagonists & inhibitors
  • Wiskott-Aldrich Syndrome Protein / chemistry*
  • Wiskott-Aldrich Syndrome Protein / metabolism*
  • cdc42 GTP-Binding Protein / metabolism

Substances

  • Actin-Related Protein 2-3 Complex
  • Actins
  • Wiskott-Aldrich Syndrome Protein
  • Phosphothreonine
  • Dyrk kinase
  • Protein-Tyrosine Kinases
  • Protein-Serine-Threonine Kinases
  • GTP Phosphohydrolases
  • cdc42 GTP-Binding Protein

Associated data

  • GENBANK/BAA21534
  • RefSeq/NP_036923