TY - JOUR
T1 - rac1 regulates a cytokine-stimulated, redox-dependent pathway necessary for NF-κB activation
AU - Sulciner, David J.
AU - Irani, Kaikobad
AU - Yu, Z. X.
AU - Ferrans, Victor J.
AU - Goldschmidt-Clermont, Pascal
AU - Finkel, Toren
PY - 1996
Y1 - 1996
N2 - The signal transduction pathway leading to the activation of the transcription factor NF-κB remains incompletely characterized. We demonstrate that in HeLa cells, transient expression of a constitutively active mutant of the small GTP-binding protein rac1 (V12rac1) leads to a significant increase in NF-κB transcriptional activity. In addition, expression of a dominant-negative rac1 mutant (N17rac1) inhibits basal and interleukin 1β-stimulated NF-κB activity. Gel shift analysis using nuclear extract prepared from HeLa cells infected with a recombinant adenovirus encoding N17rac1 (Ad.N17rac1) showed reduced levels of cytokine-stimulated DNA binding to a consensus NF-κB binding site. We demonstrate that rac proteins function downstream of ras proteins in the activation of NF-κB. In addition, V12rac1 stimulation of NF-κB activity is shown to be independent of the ability of rac proteins to activate the family of c-jun amino-terminal kinases. In an effort to further explore how rac proteins might regulate NF- κB activity, we demonstrate that expression of V12rac1 in HeLa cells or stimulation with cytokine results in a significant increase in intracellular reactive oxygen species (ROS). Treatment of cells with either of two chemically unrelated antioxidants inhibits the rise in ROS that occurs following V12rac1 expression as well as the ability of V12rac1 to stimulate NF-κB activity. These results suggest that in HeLa cells, rac1 regulates intracellular ROS production and that rac proteins function as part of a redox-dependent signal transduction pathway leading to NF-κB activation.
AB - The signal transduction pathway leading to the activation of the transcription factor NF-κB remains incompletely characterized. We demonstrate that in HeLa cells, transient expression of a constitutively active mutant of the small GTP-binding protein rac1 (V12rac1) leads to a significant increase in NF-κB transcriptional activity. In addition, expression of a dominant-negative rac1 mutant (N17rac1) inhibits basal and interleukin 1β-stimulated NF-κB activity. Gel shift analysis using nuclear extract prepared from HeLa cells infected with a recombinant adenovirus encoding N17rac1 (Ad.N17rac1) showed reduced levels of cytokine-stimulated DNA binding to a consensus NF-κB binding site. We demonstrate that rac proteins function downstream of ras proteins in the activation of NF-κB. In addition, V12rac1 stimulation of NF-κB activity is shown to be independent of the ability of rac proteins to activate the family of c-jun amino-terminal kinases. In an effort to further explore how rac proteins might regulate NF- κB activity, we demonstrate that expression of V12rac1 in HeLa cells or stimulation with cytokine results in a significant increase in intracellular reactive oxygen species (ROS). Treatment of cells with either of two chemically unrelated antioxidants inhibits the rise in ROS that occurs following V12rac1 expression as well as the ability of V12rac1 to stimulate NF-κB activity. These results suggest that in HeLa cells, rac1 regulates intracellular ROS production and that rac proteins function as part of a redox-dependent signal transduction pathway leading to NF-κB activation.
UR - http://www.scopus.com/inward/record.url?scp=0029912652&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0029912652&partnerID=8YFLogxK
M3 - Article
C2 - 8943367
AN - SCOPUS:0029912652
SN - 0270-7306
VL - 16
SP - 7115
EP - 7121
JO - Molecular and Cellular Biology
JF - Molecular and Cellular Biology
IS - 12
ER -