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Endomembrane HRas controls the PI3 kinase/Akt/eNOS signaling cascade in VEGF induced endothelial cell migration
Author(s) -
Haeussler Dagmar,
Burgoyne Joseph R,
Hou Xiuyun,
Pimental David R,
Cohen Richard A,
Bachschmid Markus M
Publication year - 2013
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.27.1_supplement.1051.1
Subject(s) - hras , endomembrane system , microbiology and biotechnology , enos , protein kinase b , pi3k/akt/mtor pathway , chemistry , nitric oxide , biology , phosphorylation , signal transduction , biochemistry , nitric oxide synthase , endoplasmic reticulum , golgi apparatus , organic chemistry , kras , mutation , gene
We demonstrate for the first time that endomembrane‐delimited HRas mediates VEGF‐induced activation of eNOS and migratory response of human endothelial cells. Using thiol labeling strategies and immunofluorescent cell staining, we found that only 31% of total HRas is S‐palmitoylated, tethering the small GTPase to the plasma membrane but leaving the function of the large majority of endomembrane localized HRas unexplained. Knock‐down of HRas blocked VEGF‐induced PI3K‐dependent Akt (S473) and eNOS (S1177) phosphorylation and nitric oxide‐dependent cell migration, demonstrating the essential role of HRas. Activation of endogenous HRas led to recruitment and phosphorylation of eNOS at endomembranes. The loss of migratory response in cells lacking endogenous HRas was fully restored by modest overexpression of an endomembrane‐delimited HRas palmitoylation mutant. These studies define a newly recognized endomembrane localization of HRas‐mediated nitric oxide‐dependent proangiogenic signaling.