AMP-Activated Protein Kinase and Sirtuin 1 Coregulation of Cortactin Contributes to Endothelial Function

Arterioscler Thromb Vasc Biol. 2016 Dec;36(12):2358-2368. doi: 10.1161/ATVBAHA.116.307871. Epub 2016 Oct 6.

Abstract

Objective: Cortactin translocates to the cell periphery in vascular endothelial cells (ECs) on cortical-actin assembly in response to pulsatile shear stress. Because cortactin has putative sites for AMP-activated protein kinase (AMPK) phosphorylation and sirtuin 1 (SIRT1) deacetylation, we examined the hypothesis that AMPK and SIRT1 coregulate cortactin dynamics in response to shear stress.

Approach and results: Analysis of the ability of AMPK to phosphorylate recombinant cortactin and oligopeptides whose sequences matched AMPK consensus sequences in cortactin pointed to Thr-401 as the site of AMPK phosphorylation. Mass spectrometry confirmed Thr-401 as the site of AMPK phosphorylation. Immunoblot analysis with AMPK siRNA and SIRT1 siRNA in human umbilical vein ECs and EC-specific AMPKα2 knockout mice showed that AMPK phosphorylation of cortactin primes SIRT1 deacetylation in response to shear stress. Immunoblot analyses with cortactin siRNA in human umbilical vein ECs, phospho-deficient T401A and phospho-mimetic T401D mutant, or aceto-deficient (9K/R) and aceto-mimetic (9K/Q) showed that cortactin regulates endothelial nitric oxide synthase activity. Confocal imaging and sucrose-density gradient analyses revealed that the phosphorylated/deacetylated cortactin translocates to the EC periphery facilitating endothelial nitric oxide synthase translocation from lipid to nonlipid raft domains. Knockdown of cortactin in vitro or genetic reduction of cortactin expression in vivo in mice substantially decreased the endothelial nitric oxide synthase-derived NO bioavailability. In vivo, atherosclerotic lesions increase in ApoE-/-/cortactin+/- mice, when compared with ApoE-/-/cortactin+/+ littermates.

Conclusions: AMPK phosphorylation of cortactin followed by SIRT1 deacetylation modulates the interaction of cortactin and cortical-actin in response to shear stress. Functionally, this AMPK/SIRT1 coregulated cortactin-F-actin dynamics is required for endothelial nitric oxide synthase subcellular translocation/activation and is atheroprotective.

Keywords: AMP-activated protein kinases; atherosclerosis; caveolin-1; cortactin; nitric oxide synthase type III.

MeSH terms

  • AMP-Activated Protein Kinases / deficiency
  • AMP-Activated Protein Kinases / genetics
  • AMP-Activated Protein Kinases / metabolism*
  • Acetylation
  • Actins / metabolism
  • Animals
  • Apolipoproteins E / deficiency
  • Apolipoproteins E / genetics
  • Atherosclerosis / genetics
  • Atherosclerosis / metabolism*
  • Atherosclerosis / prevention & control
  • Cells, Cultured
  • Cortactin / deficiency*
  • Cortactin / genetics
  • Cortactin / metabolism*
  • Disease Models, Animal
  • Endothelial Cells / enzymology*
  • Genotype
  • Humans
  • Male
  • Mice, Knockout
  • Nitric Oxide Synthase Type III / metabolism
  • Phenotype
  • Phosphorylation
  • Protein Transport
  • Pulsatile Flow
  • RNA Interference
  • Signal Transduction
  • Sirtuin 1 / genetics
  • Sirtuin 1 / metabolism*
  • Stress, Mechanical
  • Transfection

Substances

  • Actins
  • Apolipoproteins E
  • CTTN protein, human
  • Cortactin
  • Cttn protein, mouse
  • NOS3 protein, human
  • Nitric Oxide Synthase Type III
  • Nos3 protein, mouse
  • AMPK alpha2 subunit, mouse
  • PRKAA2 protein, human
  • AMP-Activated Protein Kinases
  • SIRT1 protein, human
  • Sirt1 protein, mouse
  • Sirtuin 1