c-Src regulates Nrf2 activity through PKCδ after oxidant stimulus.

Nrf2 is the main transcription factor involved in expression of cell defense enzymes, which is altered in several oxidant-related disorders. Cytosolic Nrf2 activation is modulated through phosphorylation by PKCδ, an enzyme controlled by Src tyrosine kinases. Of relevance, Src family members are involved in numerous cellular processes and regulated by hydrogen peroxide (HO). In this study we analysed the activation of cell survival-related signaling proteins, c-Src and Nrf2, and the influence of c-Src kinase on Nrf2 regulation after exposure to HO. Acute exposure of HT22 mouse hippocampal neural cells to HO increased c-Src and Nrf2 phosphorylation/activation at Tyr416 and Ser40, respectively. Nrf2 phosphorylation at Ser40, its nuclear accumulation and transcriptional activity involving heme oxygenase-1 (HO-1) expression were dependent on c-Src kinase activation. Moreover, modulation of Nrf2 activity by c-Src occurred through PKCδ phosphorylation at Tyr311. We demonstrate, for the first time, c-Src-mediated regulation of Nrf2 transcriptional activity, via PKCδ activation, following an acute HO stimulus. This work supports that the c-Src/PKCδ/Nrf2 pathway may constitute a novel signaling pathway stimulated by HO and a potential target for the treatment of diseases involving redox deregulation.