Caveolin 1 and G-Protein-Coupled Receptor Kinase-2 Coregulate Endothelial Nitric Oxide Synthase Activity in Sinusoidal Endothelial Cells.


Journal Article

Liver injury leads to a vasculopathy in which post-translational modifications of endothelial nitric oxide synthase (eNOS) lead to impaired nitric oxide synthesis. We hypothesized that caveolin 1 (CAV1), a well-known eNOS interactor, regulates eNOS activity in sinusoidal endothelial cells (SECs) via its interaction with G-protein-coupled receptor kinase-2 (GRK2) that also post-translationally modifies eNOS. Liver injury with portal hypertension was established using bile duct ligation in rats. CAV1 function was modified using a CAV1 scaffolding domain construct and cDNAs encoding wild-type CAV1, and CAV1 phosphorylation was increased in injured SECs, resulting in increased GRK2-CAV1 interaction and decreased eNOS activity. In injured SECs, endothelin-1 blocked CAV1 phosphorylation induced by CAV1 scaffolding domain, indicating that CAV1 interaction with GRK2 is inversely regulated by endothelin-1 and CAV1 scaffolding domain after liver injury. In addition, after transduction with DNA encoding wild-type CAV1 into SECs isolated from Cav1-deficient mice, GRK2 association with CAV1 was evident, whereas transduction with a dominant negative CAV1 mutated at tyrosine 14 reduced the interaction. Finally, isoproterenol-induced GRK2 phosphorylation enhanced CAV1-GRK2 interaction and reduced eNOS activity. Our data suggest a novel mechanism and model in which CAV1 phosphorylation facilitates CAV1 scaffolding and GRK2-CAV1 interaction, thus clustering eNOS within a complex that inhibits eNOS activity. This process takes place in injured, but not in normal, SECs.

Full Text

Cited Authors

  • Liu, S; Premont, RT; Singh, S; Rockey, DC

Published Date

  • April 2017

Published In

Volume / Issue

  • 187 / 4

Start / End Page

  • 896 - 907

PubMed ID

  • 28162981

Pubmed Central ID

  • 28162981

Electronic International Standard Serial Number (EISSN)

  • 1525-2191

International Standard Serial Number (ISSN)

  • 0002-9440

Digital Object Identifier (DOI)

  • 10.1016/j.ajpath.2016.11.017


  • eng