Proline-rich tyrosine kinase 2 (Pyk2) mediates vascular endothelial-cadherin-based cell-cell adhesion by regulating beta-catenin tyrosine phosphorylation

J Biol Chem. 2005 Jun 3;280(22):21129-36. doi: 10.1074/jbc.M500898200. Epub 2005 Mar 18.


Vascular endothelial-cadherin (VE-cadherin) controls endothelial cell-cell adhesion and preserves endothelial integrity. In order to maintain endothelial barrier function, VE-cadherin function is tightly regulated through mechanisms that involve protein phosphorylation and cytoskeletal dynamics. Here, we show that loss of VE-cadherin function results in intercellular gap formation and a drop in electrical resistance of monolayers of primary human endothelial cells. Detailed analysis revealed that loss of endothelial cell-cell adhesion, induced by VE-cadherin-blocking antibodies, is preceded by and dependent on a rapid activation of Rac1 and increased production of reactive oxygen species. Moreover, VE-cadherin-associated beta-catenin is tyrosine-phosphorylated upon loss of cell-cell contact. Finally, the redox-sensitive proline-rich tyrosine kinase 2 (Pyk2) is activated and recruited to cell-cell junctions following the loss of VE-cadherin homotypic adhesion. Conversely, the inhibition of Pyk2 activity in endothelial cells by the expression of CRNK (CADTK/CAKbeta-related non-kinase), an N-terminal deletion mutant that acts in a dominant negative fashion, not only abolishes the increase in beta-catenin tyrosine phosphorylation but also prevents the loss of endothelial cell-cell contact. These results implicate Pyk2 in the reduced cell-cell adhesion induced by the Rac-mediated production of ROS through the tyrosine phosphorylation of beta-catenin. This signaling is initiated upon loss of VE-cadherin function and is important for our insight in the modulation of endothelial integrity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • ADP-Ribosylation Factors / chemistry
  • ADP-Ribosylation Factors / physiology*
  • Adenoviridae / genetics
  • Antigens, CD
  • Cadherins / metabolism*
  • Cell Adhesion
  • Cell Communication
  • Cells, Cultured
  • Cytoskeletal Proteins / chemistry
  • Cytoskeletal Proteins / metabolism*
  • Cytoskeleton / metabolism
  • Electric Impedance
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / metabolism
  • Focal Adhesion Kinase 2
  • GTPase-Activating Proteins / chemistry
  • GTPase-Activating Proteins / physiology*
  • Gene Deletion
  • Genes, Dominant
  • Humans
  • Immunohistochemistry
  • Immunoprecipitation
  • Mutation
  • Oxidation-Reduction
  • Peptides / chemistry
  • Permeability
  • Phosphorylation
  • Proline / chemistry
  • Protein Structure, Tertiary
  • Protein-Tyrosine Kinases / physiology*
  • Reactive Oxygen Species
  • Signal Transduction
  • Time Factors
  • Trans-Activators / chemistry
  • Trans-Activators / metabolism*
  • Tyrosine / chemistry
  • Tyrosine / metabolism
  • Umbilical Veins / cytology
  • Vascular Endothelial Growth Factor A / metabolism*
  • beta Catenin
  • rac1 GTP-Binding Protein / metabolism


  • Antigens, CD
  • CTNNB1 protein, human
  • Cadherins
  • Cytoskeletal Proteins
  • FAT1 protein, human
  • GTPase-Activating Proteins
  • Peptides
  • Reactive Oxygen Species
  • Trans-Activators
  • Vascular Endothelial Growth Factor A
  • beta Catenin
  • cadherin 5
  • Tyrosine
  • Proline
  • Protein-Tyrosine Kinases
  • Focal Adhesion Kinase 2
  • ASAP2 protein, human
  • ADP-Ribosylation Factors
  • rac1 GTP-Binding Protein