Tyrosine phosphorylation of WIP releases bound WASP and impairs podosome assembly in macrophages

Vineetha Vijayakumar, James Monypenny, Xing Judy Chen, Laura M Machesky, Sergio Lilla, Adrian J Thrasher, Inés M Antón, Yolanda Calle, Gareth E Jones

Research output: Contribution to journalArticlepeer-review


Podosomes are integrin-containing adhesion structures commonly found in migrating leukocytes of the monocytic lineage. The actin cytoskeletal organisation of podosomes is based on a WASP- and Arp2/3-mediated mechanism. WASP also associates with a second protein, WIP (also known as WIPF1), and they co-localise in podosome cores. Here, we report for the first time that WIP can be phosphorylated on tyrosine residues and that tyrosine phosphorylation of WIP is a trigger for release of WASP from the WIP-WASP complex. Using a knockdown approach together with expression of WIP phosphomimics, we show that in the absence of WIP-WASP binding, cellular WASP is rapidly degraded, leading to disruption of podosomes and a failure of cells to degrade an underlying matrix. In the absence of tyrosine phosphorylation, the WIP-WASP complex remains intact and podosome lifetimes are extended. A screen of candidate kinases and inhibitor-based assays identified Bruton's tyrosine kinase (Btk) as a regulator of WIP tyrosine phosphorylation. We conclude that tyrosine phosphorylation of WIP is a crucial regulator of WASP stability and function as an actin-nucleation-promoting factor.

Original languageEnglish
Pages (from-to)251-265
Number of pages15
JournalJournal of Cell Science
Issue number2
Publication statusPublished - 14 Jan 2015


  • Actin Cytoskeleton
  • Animals
  • Cytoskeletal Proteins
  • Extracellular Matrix
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Macrophages
  • Phosphorylation
  • Podosomes
  • Protein Binding
  • Protein-Tyrosine Kinases
  • Tyrosine
  • Wiskott-Aldrich Syndrome Protein

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