Paxillin mediates stretch-induced Rho signaling and endothelial permeability via assembly of paxillin-p42/44MAPK-GEF-H1 complex.
Suboptimal ventilator support or regional ventilation heterogeneity in inflamed lungs causes excessive tissue distension, which triggers stretch-induced pathological signaling and may lead to vascular leak and lung dysfunction. Focal adhesions (FAs) are cell-substrate adhesive complexes participating in cellular mechanotransduction and regulation of the Rho GTPase pathway. Stretch-induced Rho regulation remains poorly understood. We used human lung endothelial cells (ECs) exposed to pathological cyclic stretch (CS) at 18% distension to test the hypothesis that FA protein paxillin participates in CS-induced Rho activation by recruiting the Rho-specific guanine nucleotide exchange factor GEF-H1. CS induced phosphorylation of paxillin and activated p42/44-MAP kinase, Rho GTPase, and paxillin/GEF-H1/p42/44-MAPK association. CS caused nearly 2-fold increase in EC permeability, which was attenuated by paxillin knockdown. Expression of the paxillin-Y31/118F phosphorylation mutant decreased the CS-induced paxillin/GEF-H1 association (16.3 ± 4.1%), GEF-H1 activation (28.9 ± 9.2%), and EC permeability (28.7 ± 8.1%) but not CS-induced p42/44-MAPK activation. Inhibition of p42/44-MAPK suppressed CS-induced paxillin/GEF-H1 interactions (15.9 ± 7.9%), GEF-H1 activation (11.7 ± 4.3%), and disruption of EC monolayer. Expression of GEF-H1T678A lacking p42/44-MAPK phosphorylation site attenuated Rho activation (31.2±11.6%). We conclude that MAPK-dependent targeting of GEF-H1 to paxillin is involved in the regulation of CS-induced Rho signaling and EC permeability. This study proposes a novel concept of paxillin-GEF-H1-p42/44-MAPK module as a regulator of pathological mechanotransduction.-Gawlak, G., Tian, Y., O'Donnell, J. J., III, Tian, X., Birukova, A. A., Birukov, K. G. Paxillin mediates stretch-induced Rho signaling and endothelial permeability via assembly of paxillin-p42/44MAPK-GEF-H1 complex.
Lung Injury Center, Department of Medicine, University of Chicago, Chicago, Illinois, USA.
Grzegorz
G
Gawlak
Lung Injury Center, Department of Medicine, University of Chicago, Chicago, Illinois, USA.
Yufeng
Y
Tian
Lung Injury Center, Department of Medicine, University of Chicago, Chicago, Illinois, USA.
James J
JJ
O'Donnell
Lung Injury Center, Department of Medicine, University of Chicago, Chicago, Illinois, USA.
Xinyong
X
Tian
Lung Injury Center, Department of Medicine, University of Chicago, Chicago, Illinois, USA.
Anna A
AA
Birukova
Lung Injury Center, Department of Medicine, University of Chicago, Chicago, Illinois, USA kbirukov@medicine.bsd.uchicago.edu.
Konstantin G
KG
Birukov
D002199:Capillary Permeability / Q000502:physiology*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism*; D006801:Humans; D008168:Lung / Q000378:metabolism / Q000502:physiology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D051419:Paxillin / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology; D064067:Rho Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D020741:rho GTP-Binding Proteins / Q000378:metabolism*
C577356:ARHGEF2 protein, human; D051419:Paxillin; D064067:Rho Guanine Nucleotide Exchange Factors; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020741:rho GTP-Binding Proteins
cytoskeleton; focal adhesions; guanine nucleotide exchange factors; mechanotransduction