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Ubiquitination of PAR1 nucleates a non‐canonical p38 signaling pathway to regulate thrombin‐induced vascular leakage (1066.15)
Author(s) -
Grimsey Neil,
Smith Thomas,
Le Philip,
Trejo JoAnn
Publication year - 2014
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.28.1_supplement.1066.15
Subject(s) - microbiology and biotechnology , autophosphorylation , thrombin , ubiquitin , signal transduction , signal transducing adaptor protein , ubiquitin ligase , chemistry , p38 mitogen activated protein kinases , phosphorylation , biology , biochemistry , protein kinase a , immunology , mapk/erk pathway , platelet , gene
Thrombin activation of the protease‐activated receptor‐1 (PAR1), a GPCR, triggers inflammation, endothelial barrier permeability and vascular leakage. Multiple signaling pathways contribute to vascular leakage including activation of the p38 MAP kinase. However, the precise mechanism of PAR1‐stimulated p38 activation is not known. In this study, we examined the role of PAR1 ubiquitination in the activation of p38 signaling and endothelial barrier dysfunction. We demonstrate that thrombin activation of PAR1 stimulates p38 signaling via a novel ubiquitin/TAB1/TAB2‐induced p38 autophosphorylation pathway. Thrombin‐induced ubiquitination of PAR1 is mediated by the activation and recruitment of the E3 ubiquitin ligase NEDD4‐2. The adaptor protein TAB2 then binds to ubiquitinated PAR1 and recruits another adaptor TAB1. TAB1 also binds and triggers p38 activation through autophosphorylation and not the MKK3/MKK6 pathway. This pathway is conserved for ADP‐dependent activation of the P2Y1 purinergic receptor. We further demonstrate that thrombin activation of PAR1 requires non‐canonical p38‐signaling pathway to regulate barrier permeability of cultured human endothelial cells. Collectively, these data suggest that a subset of GPCRs utilize ubiquitin to assemble and activate a TAB2 and TAB1 non‐canonical p38 signaling complex that regulates endothelial barrier permeability and vascular leakage. Grant Funding Source : Supported by NIH R01 HL073328 and Western States Affiliate AHA Postdoctoral Fellowship