p120 regulates endothelial permeability independently of its NH2 terminus and Rho binding.
The association of p120-catenin (p120) with the juxtamembrane domain (JMD) of vascular endothelial (VE)-cadherin is required to maintain VE-cadherin levels and transendothelial resistance (TEER) of endothelial cell monolayers. To distinguish whether decreased TEER was due to a loss of p120 and not to the decrease in VE-cadherin, we established a system in which p120 was depleted by short hairpin RNA delivered by lentivirus and VE-cadherin was restored via expression of VE-cadherin fused to green fluorescent protein (GFP). Loss of p120 resulted in decreased TEER, which was associated with decreased expression of VE-cadherin, β-catenin, plakoglobin, and α-catenin. Decreased TEER was rescued by restoration of p120 but not by the expression of VE-cadherin-GFP, despite localization of VE-cadherin-GFP at cell-cell borders. Expression of VE-cadherin-GFP restored levels of β-catenin and α-catenin but not plakoglobin, indicating that p120 may be important for recruitment of plakoglobin to the VE-cadherin complex. To evaluate the role of p120 interaction with Rho GTPase in regulating endothelial permeability, we expressed a recombinant form of p120, lacking the NH(2) terminus and containing alanine substitutions, that eliminates binding of Rho to p120. Expression of this isoform restored expression of the adherens junction complex and rescued permeability as measured by TEER. These results demonstrate that p120 is required for maintaining VE-cadherin expression and TEER independently of its NH(2) terminus and its role in regulating Rho.
Herron
Crystal R
CR
Center for Cardiovascular Sciences, Albany Medical College, Albany, New York, USA.
Lowery
Anthony M
AM
Hollister
Patricia R
PR
Reynolds
Albert B
AB
Vincent
Peter A
PA
D000704:Analysis of Variance; D015820:Cadherins / Q000378:metabolism; D051177:Catenins / Q000378:metabolism*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006801:Humans; D010539:Permeability; D034622:RNA Interference; D051185:gamma Catenin / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000378:metabolism*; D000095002:Delta Catenin
D015820:Cadherins; D051177:Catenins; D051185:gamma Catenin; D020741:rho GTP-Binding Proteins; D000095002:Delta Catenin; C000722347:CTNND1 protein, human