RT Journal Article
T1 Glycogen Synthase Kinase-3beta inhibits the xenobiotic and antioxidant cell response by direct phosphorylation and nuclear exclusion of the Transcription Factor Nrf2
A1 Salazar Roa, María
A1 Rojo, Ana
A1 Velasco, Diego
A1 Sagarra, Rosa María
A1 Cuadrado, Antonio
AB The transcription factor Nrf2 (nuclear factor E2-related factor 2) regulates the expression of antioxidant phase II genes and contributes to preserve redox homeostasis and cell viability in response to oxidant insults. Nrf2 should be coordinated with the canonical cell survival pathway represented by phosphatidylinositol 3-kinase (PI3K) and the Ser/Thr kinase Akt but so far the mechanistic connections remain undefined. Here we identify glycogen synthase kinase-3β (GSK-3β), which is inhibited by Akt-mediated phosphorylation, as the link between both processes. Using heme oxygenase-1 (HO-1) as a model phase II gene, we found that both PI3K and Akt increased mRNA and protein levels of this enzyme. Pharmacological inhibitors (LiCl and PDZD-8) and genetic variants of GSK-3β (constitutively active and dominant negative mutants) indicated that PI3K/Akt activates and GSK-3β inhibits the antioxidant response elements of the ho1 promoter and pointed Nrf2 as directly involved in this process. Indeed, GSK-3β phosphorylated Nrf2 in vitro and in vivo. Immunocytochemistry and subcellular fractionation analyses demonstrated that the effect of GSK-3β-mediated phosphorylation of Nrf2 is to exclude this transcription factor from the nucleus. Nrf2 up-regulated the expression of HO-1, glutathione peroxidase, glutathione S-transferase A1, NAD(P)H: quinone oxidoreductase and glutamate-cysteine ligase and protected against hydrogen peroxide-induced glutathione depletion and cell death, whereas co-expression of active GSK-3β attenuated both phase II gene expression and oxidant protection. These results contribute to clarify the cross-talk between the survival signal elicited by PI3K/Akt and the antioxidant phase II cell response, and introduce GSK-3β as the key mediator of this regulation mechanism.
PB Elsevier
SN 0021-9258
YR 2006
FD 2006
LK https://hdl.handle.net/20.500.14352/95066
UL https://hdl.handle.net/20.500.14352/95066
LA eng
NO María Salazar, Ana I. Rojo, Diego Velasco, Rosa María de Sagarra, Antonio Cuadrado, Glycogen Synthase Kinase-3β Inhibits the Xenobiotic and Antioxidant Cell Response by Direct Phosphorylation and Nuclear Exclusion of the Transcription Factor Nrf2*, Journal of Biological Chemistry, Volume 281, Issue 21, 2006, Pages 14841-14851, ISSN 0021-9258, https://doi.org/10.1074/jbc.M513737200.
NO This work was supported by Grant SAF2004-02039 from Spanish Ministry of Education (MEC), GR/SAL/0198/2004 from the Community of Madrid, and RSMN(03/08) from the Health Institute Carlos III.
NO Ministerio de Educación (España)
NO Instituto de Salud Carlos III
NO Comunidad de Madrid
DS Docta Complutense
RD 17 abr 2025