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

TY - JOUR

T1 - Tyrosine phosphorylation of WIP releases bound WASP and impairs podosome assembly in macrophages

AU - Vijayakumar, Vineetha

AU - Monypenny, James

AU - Chen, Xing Judy

AU - Machesky, Laura M

AU - Lilla, Sergio

AU - Thrasher, Adrian J

AU - Antón, Inés M

AU - Calle, Yolanda

AU - Jones, Gareth E

N1 - © 2015. Published by The Company of Biologists Ltd.

PY - 2015/1/14

Y1 - 2015/1/14

N2 - 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.

AB - 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.

KW - Actin Cytoskeleton

KW - Animals

KW - Cytoskeletal Proteins

KW - Extracellular Matrix

KW - Humans

KW - Intracellular Signaling Peptides and Proteins

KW - Macrophages

KW - Phosphorylation

KW - Podosomes

KW - Protein Binding

KW - Protein-Tyrosine Kinases

KW - Tyrosine

KW - Wiskott-Aldrich Syndrome Protein

U2 - 10.1242/jcs.154880

DO - 10.1242/jcs.154880

M3 - Article

C2 - 25413351

SN - 1477-9137

VL - 128

SP - 251

EP - 265

JO - Journal of Cell Science

JF - Journal of Cell Science

IS - 2

ER -