Regulation of gene expression by the small GTPase Rho through the ERK6 (p38γ) MAP kinase pathway
Abstract
Small GTP-binding proteins of the Rho-family, Rho, Rac, and Cdc42, have been traditionally linked to the regulation of the cellular actin-based cytoskeleton. Rac and Cdc42 can also control the activity of JNK, thus acting in a molecular pathway transmitting extracellular signals to the nucleus. Interestingly, Rho can also regulate gene expression, albeit by a not fully understood mechanism. Here, we found that activated RhoA can stimulate c-jun expression and the activity of the c-jun promoter. As the complexity of the signaling pathways controlling the expression of c-jun has begun to be unraveled, this finding provided a unique opportunity to elucidate the biochemical routes whereby RhoA regulates nuclear events. We found that RhoA can initiate a linear kinase cascade leading to the activation of ERK6 (p38γ), a recently identified member of the p38 family of MAPKs. Furthermore, we present evidence that RhoA, PKN, MKK3/MKK6, and ERK6 (p38γ) are components of a novel signal transduction pathway involved in the regulation of gene expression and cellular transformation.
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Footnotes
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↵1 Corresponding author.
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E-MAIL sg39v{at}nih.gov; FAX (301) 402-0823.
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Article and publication are at www.genesdev.org/cgi/doi/10.1101/gad.855801.
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- Received September 28, 2000.
- Accepted January 4, 2001.
- Cold Spring Harbor Laboratory Press