Molecular regulation of NADPH oxidase 5 via the MAPK pathway

D. Pandey, D. J.R. Fulton

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

The mechanisms controlling the activity of NADPH oxidase 5 (Nox5) are unique in that they are independent of the protein: protein interactions that coordinate the activation of other Nox isoforms. Instead, the primary driving force for Nox5 activity is calcium. However, in a previous study we reported that the protein kinase C (PKC)-agonist PMA could induce a sustained activation of Nox5 that was independent of calcium changes. This apparent calcium-independent activation was found to be mediated by the PKC-dependent phosphorylation of specific serine and threonine residues on Nox5 which increased the calcium sensitivity of the enzyme and enabled activation at resting levels of calcium. However, the specific kinase(s) mediating the phosphorylation and activation of Nox5 are not known. As PKC can activate the MEK/ERK1/2 signaling pathway, we hypothesized that Nox5 is activated by the coordinated phosphorylation of both MAPK and PKC pathways. The inhibition of MEK1 using PD-98059 and U-0126 significantly reduced the phosphorylation and activity of Nox5 in response to PMA but not to the calcium-mobilizing stimulus ionomycin. Dominant negative MEK1 and knockdown of endogenous MEK1/2 using a specific small interfering RNA also inhibited Nox5 activity in response to PMA. The mutation of S498 to a nonphosphorylatable residue and to a lesser degree T494 blocked the ability of ERK to stimulate Nox5 activity. However, a constitu-tively active form of MEK1 failed to increase Nox5 activity in the absence of PMA stimulation. These results suggest that the MEK/ ERK1/2 pathway is necessary but not sufficient to regulate the PMA-dependent activation of Nox5.

Original languageEnglish (US)
Pages (from-to)H1336-H1344
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume300
Issue number4
DOIs
StatePublished - Apr 1 2011

Fingerprint

NADPH Oxidase
Calcium
Protein Kinase C
Mitogen-Activated Protein Kinase Kinases
Phosphorylation
MAP Kinase Signaling System
Ionomycin
Enzyme Activation
Threonine
Serine
Small Interfering RNA
Protein Isoforms
Proteins
Phosphotransferases

Keywords

  • Mitogen-activated protein kinase
  • Protein kinase C
  • Reactive oxygen species
  • Reduced nicotinamide adenine dinucleotide phosphate oxidase 5

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Molecular regulation of NADPH oxidase 5 via the MAPK pathway. / Pandey, D.; Fulton, D. J.R.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 300, No. 4, 01.04.2011, p. H1336-H1344.

Research output: Contribution to journalArticle

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