Role of Ras-dependent ERK activation in phorbol ester-induced endothelial cell barrier dysfunction

Alexander D. Verin, Feng Liu, Natalia Bogatcheva, Talaibek Borbiev, Marc B. Hershenson, Peiyi Wang, Joe G.N. Garcia

Research output: Contribution to journalArticlepeer-review

85 Scopus citations


The treatment of endothelial cell monolayers with phorbol 12-myristate 13-acetate (PMA), a direct protein kinase C (PKC) activator, leads to disruption of endothelial cell monolayer integrity and intercellular gap formation. Selective inhibition of PKC (with bisindolylmaleimide) and extracellular signal-regulated kinases (ERKs; with PD-98059, olomoucine, or ERK antisense oligonucleotides) significantly attenuated PMA-induced reductions in transmonolayer electrical resistance consistent with PKC- and ERK-mediated endothelial cell barrier regulation. An inhibitor of the dual-specificity ERK kinase (MEK), PD-98059, completely abolished PMA-induced ERK activation. PMA also produced significant time-dependent increases in the activity of Raf-1, a Ser/Thr kinase known to activate MEK (~6-fold increase over basal level). Similarly, PMA increased the activity of Ras, which binds and activates Raf-1 (~80% increase over basal level). The Ras inhibitor farnesyltransferase inhibitor III (100 μM for 3 h) completely abolished PMA-induced Raf-1 activation. Taken together, these data suggest that the sequential activation of Ras, Raf-1, and MEK are involved in PKC-dependent endothelial cell barrier regulation.

Original languageEnglish (US)
Pages (from-to)L360-L370
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Issue number2 23-2
StatePublished - 2000


  • Cytoskeleton
  • Extracellular signal-regulated kinase
  • Mitogen-activated protein kinases

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology


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