title: Tyrosine phosphorylation of WIP releases bound WASP and impairs podosome assembly in macrophages.
abstract: 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.
authors.affiliation: Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK.
authors.forename: Vineetha
authors.initials: V
authors.lastname: Vijayakumar
authors.affiliation: Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK.
authors.forename: James
authors.initials: J
authors.lastname: Monypenny
authors.affiliation: Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK.
authors.forename: Xing Judy
authors.initials: XJ
authors.lastname: Chen
authors.affiliation: The Beatson Institute for Cancer Research, Glasgow G61 1BD, UK.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Machesky
authors.affiliation: The Beatson Institute for Cancer Research, Glasgow G61 1BD, UK.
authors.forename: Sergio
authors.initials: S
authors.lastname: Lilla
authors.affiliation: Section of Molecular and Cellular Immunology, Institute of Child Health, University College London, London WC1N 1EH, UK.
authors.forename: Adrian J
authors.initials: AJ
authors.lastname: Thrasher
authors.affiliation: Centro Nacional de Biotecnología (CNB-CSIC), 28049 Madrid, Spain.
authors.forename: Inés M
authors.initials: IM
authors.lastname: Antón
authors.affiliation: Department of Haematological & Molecular Medicine, King's College London, London SE5 9NU, UK.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Calle
authors.affiliation: Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK gareth.jones@kcl.ac.uk.
authors.forename: Gareth E
authors.initials: GE
authors.lastname: Jones
mesh_terms: D008841:Actin Cytoskeleton / Q000235:genetics / Q000378:metabolism; D000077329:Agammaglobulinaemia Tyrosine Kinase; D000818:Animals; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D005109:Extracellular Matrix / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism; D010766:Phosphorylation / Q000235:genetics; D000069261:Podosomes / Q000378:metabolism; D011485:Protein Binding; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism; D051316:Wiskott-Aldrich Syndrome Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D003598:Cytoskeletal Proteins; D047908:Intracellular Signaling Peptides and Proteins; C109903:WIPF1 protein, human; D051316:Wiskott-Aldrich Syndrome Protein; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C000625949:BTK protein, human
keywords: Actin cytoskeleton; Macrophages; Matrix degradation; Podosome; Tyrosine phosphorylation; WIP; WIPF1