Phosphorylation of WASp is a key regulator of activity and stability in vivo

Michael P Blundell, Gerben Bouma, Joao Metelo, Austen Worth, Yolanda Calle, Lucy A Cowell, Lisa S Westerberg, Dale A Moulding, Samuel Mirando, Christine Kinnon, Giles O Cory, Gareth E Jones, Scott B Snapper, Siobhan O Burns, Adrian J Thrasher

Research output: Contribution to journalArticlepeer-review

Abstract

The Wiskott-Aldrich syndrome protein (WASp) is a key cytoskeletal regulator in hematopoietic cells. Covalent modification of a conserved tyrosine by phosphorylation has emerged as an important potential determinant of activity, although the physiological significance remains uncertain. In a murine knockin model, mutation resulting in inability to phosphorylate Y293 (Y293F) mimicked many features of complete WASp-deficiency. Although a phosphomimicking mutant Y293E conferred enhanced actin-polymerization, the cellular phenotype was similar due to functional dysregulation. Furthermore, steady-state levels of Y293E-WASp were markedly reduced compared to wild-type WASp and Y293F-WASp, although partially recoverable by treatment of cells with proteasome inhibitors. Consequently, tyrosine phosphorylation plays a critical role in normal activation of WASp in vivo, and is indispensible for multiple tasks including proliferation, phagocytosis, chemotaxis, and assembly of adhesion structures. Furthermore, it may target WASp for proteasome-mediated degradation, thereby providing a default mechanism for self-limiting stimulation of the Arp2/3 complex.

Original languageEnglish
Pages (from-to)15738-43
Number of pages6
JournalPROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volume106
Issue number37
DOIs
Publication statusPublished - 15 Sep 2009

Keywords

  • Actins
  • Amino Acid Substitution
  • Animals
  • Binding Sites
  • COS Cells
  • Cell Line
  • Cell Movement
  • Cercopithecus aethiops
  • Hematopoiesis
  • Humans
  • In Vitro Techniques
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mice, Transgenic
  • Mutagenesis, Site-Directed
  • Phagocytosis
  • Phosphorylation
  • Recombinant Proteins
  • Tyrosine
  • Wiskott-Aldrich Syndrome
  • Wiskott-Aldrich Syndrome Protein

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