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Ca 2+ ‐dependent Pyk2 Activation Destabilizes Endothelial Adherens Junctions by Disrupting Interaction between VE‐PTP and VE‐Cadherin
Author(s) -
Soni Dheeraj,
DebRoy Auditi,
Wang DongMei,
Vogel Stephen M,
Tiruppathi Chinnaswamy
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1138.1
Subject(s) - adherens junction , microbiology and biotechnology , ve cadherin , stim1 , tyrosine phosphorylation , phosphorylation , s1pr1 , endothelial stem cell , biology , protein tyrosine phosphatase , chemistry , cadherin , vascular endothelial growth factor a , biochemistry , cell , cancer research , endoplasmic reticulum , vascular endothelial growth factor , in vitro , vegf receptors
Expression of vascular endothelial cadherin (VE‐cad) and its interacting protein partner vascular endothelial protein tyrosine phosphatase (VE‐PTP) at endothelial Adherens Junctions (AJs) is vital for endothelial barrier integrity. Previously, we showed that s tromal i nteracting m olecule 1 (STIM1)‐activated Ca 2+ entry disassembles endothelial AJs to increase vascular permeability. However, the signaling pathways activated secondary to STIM1‐activated Ca 2+ entry (i.e., store‐operated Ca 2+ entry [SOCE]) in endothelial cells, which mediate the disassembly of endothelial AJs, are not fully understood. Here we provide genetic evidence that SOCE signaling disrupts the association between VE‐cad and VE‐PTP at endothelial AJs by activation of the Ca 2+ ‐dependent tyrosine kinase Pyk2. We generated endothelial cell‐restricted STIM1 knockout ( Stim1 ΔEC ) mice by crossing loxP‐flanked STIM1 ( Stim1 fl/fl ) mice with Cdh5‐Cre transgenic mice. Lung endothelial cells (LECs) from Stim1 ΔEC mice showed abrogation of SOCE in response to protease‐activated receptor‐1 (PAR‐1) activation with either thrombin or PAR‐1 agonist peptide (TFLLRNPNDK‐NH 2 ). Further, we observed that PAR‐1‐induced Pyk2 activation (measured by Pyk2 phosphorylation at Tyr‐402) and VE‐PTP inactivation (measured by VE‐PTP phosphorylation) were prevented in LECs of Stim1 ΔEC mice. Consistent with these results, PAR‐1 induced VE‐cad phosphorylation was markedly suppressed in LECs from Stim1 ΔEC mice. As expected, PAR‐1 activation failed to disassemble endothelial AJs in LECs of Stim1 ΔEC mice. Moreover, pharmacological inhibition or silencing of Pyk2 in human lung vascular endothelial cells prevented endothelial AJ disassembly and inactivation of VE‐PTP in response to thrombin. These findings suggest that SOCE signaling regulates endothelial AJs through Pyk2‐mediated inactivation of VE‐PTP. Support or Funding Information NIH/HLBI 1R01HL128359‐01