Pyk2 phosphorylation of VE-PTP downstream of STIM1-induced Ca 2+ entry regulates disassembly of adherens junctions

Am J Physiol Lung Cell Mol Physiol. 2017 Jun 1;312(6):L1003-L1017. doi: 10.1152/ajplung.00008.2017. Epub 2017 Apr 6.

Abstract

Vascular endothelial protein tyrosine phosphatase (VE-PTP) stabilizes endothelial adherens junctions (AJs) through constitutive dephosphorylation of VE-cadherin. Here we investigated the role of stromal interaction molecule 1 (STIM1) activation of store-operated Ca2+ entry (SOCE) in regulating AJ assembly. We observed that SOCE induced by STIM1 activated Pyk2 in human lung microvascular endothelial cells (ECs) and induced tyrosine phosphorylation of VE-PTP at Y1981. Pyk2-induced tyrosine phosphorylation of VE-PTP promoted Src binding to VE-PTP, Src activation, and subsequent VE-cadherin phosphorylation and thereby increased the endothelial permeability response. The increase in permeability was secondary to disassembly of AJs. Pyk2-mediated responses were blocked in EC-restricted Stim1 knockout mice, indicating the requirement for STIM1 in initiating the signaling cascade. A peptide derived from the Pyk2 phosphorylation site on VE-PTP abolished the STIM1/SOCE-activated permeability response. Thus Pyk2 activation secondary to STIM1-induced SOCE causes tyrosine phosphorylation of VE-PTP, and VE-PTP, in turn, binds to and activates Src, thereby phosphorylating VE-cadherin to increase endothelial permeability through disassembly of AJs. Our results thus identify a novel signaling mechanism by which STIM1-induced Ca2+ signaling activates Pyk2 to inhibit the interaction of VE-PTP and VE-cadherin and hence increase endothelial permeability. Therefore, targeting the Pyk2 activation pathway may be a potentially important anti-inflammatory strategy.

Keywords: Pyk2; VE-cadherin; permeability increase; store-operated Ca2+ entry; stromal interaction molecule 1; thrombin; vascular endothelial protein tyrosine phosphatase.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adherens Junctions / metabolism*
  • Animals
  • Antigens, CD / metabolism
  • Cadherins / metabolism
  • Calcium / metabolism*
  • Capillary Permeability
  • Cell Membrane Permeability
  • Endothelial Cells / metabolism
  • Enzyme Activation
  • Focal Adhesion Kinase 2 / metabolism*
  • Gene Knockdown Techniques
  • Gene Silencing
  • Humans
  • Mice, Inbred C57BL
  • Microvessels / cytology
  • Models, Biological
  • Neoplasm Proteins / metabolism
  • Peptides / metabolism
  • Phosphorylation
  • Phosphotyrosine / metabolism
  • Receptor, PAR-1 / metabolism
  • Receptor-Like Protein Tyrosine Phosphatases, Class 3 / metabolism*
  • Stromal Interaction Molecule 1 / metabolism*
  • src-Family Kinases / metabolism

Substances

  • Antigens, CD
  • Cadherins
  • Neoplasm Proteins
  • Peptides
  • Receptor, PAR-1
  • STIM1 protein, human
  • Stim1 protein, mouse
  • Stromal Interaction Molecule 1
  • cadherin 5
  • Phosphotyrosine
  • Focal Adhesion Kinase 2
  • src-Family Kinases
  • Receptor-Like Protein Tyrosine Phosphatases, Class 3
  • Calcium