Related Experiment Video
Updated: Jul 4, 2026
08:05
Assaying Protein Kinase Activity with Radiolabeled ATP
Published on: May 26, 2017
WNK2 modulates MEK1 activity through the Rho GTPase pathway
Sónia Moniz1, Paulo Matos, Peter Jordan
1Centre of Human Genetics, National Health Institute, Lisbon, Portugal.
Cellular Signalling
|July 3, 2008
Summary
WNK2 protein kinase regulates cell growth by modulating ERK1/2 activation. Its depletion impacts RhoA and Rac1 signaling, affecting MEK1 phosphorylation and ERK1/2 activation efficiency.
Area of Science:
- Molecular Biology
- Cell Signaling
- Cancer Research
Background:
- WNK (With No Lysine) protein kinases are crucial in multicellular organisms, with four genes in the human genome.
- Human WNK2 is a recently identified cell growth regulator impacting ERK1/2 protein kinase activation.
- Epigenetic silencing of WNK2 occurs in gliomas, suggesting its role in cancer.
Purpose of the Study:
- To elucidate the mechanism by which WNK2 influences ERK activation.
- To understand the signaling pathways regulated by WNK2 in cell growth modulation.
Main Methods:
- Investigated the effects of WNK2 depletion on RhoA and Rac1 GTP-loading.
- Assessed the activation of the Rac1-effector PAK1.
- Examined the phosphorylation of MEK1 at serine 298 and its effect on MEK1-ERK1/2 affinity.
Main Results:
- WNK2 depletion led to decreased RhoA activation and increased Rac1 GTP-loading.
- This promoted PAK1 stimulation, resulting in MEK1 phosphorylation at serine 298.
- Increased MEK1 phosphorylation enhanced its affinity for ERK1/2, modulating ERK activation.
Conclusions:
- WNK2 acts as a regulator of ERK activation through a RhoA-mediated signaling pathway.
- WNK2 controls a cross-talk mechanism influencing MEK1's efficiency in activating ERK1/2.
- Findings provide mechanistic insight into WNK2's role in cell growth and potential implications for glioma.
Related Concept Videos
01:07MAPK Signaling Cascades
Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
01:24Small GTPases - Ras and Rho
Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:
Three regulatory proteins control their activity:
01:22PI3K/mTOR/AKT Signaling Pathway
The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast, mTORC2 consists of a rapamycin-insensitive companion...
02:54Canonical Wnt Signaling Pathway
The gene encoding the main signaling molecules of the Wnt signaling pathways (the Wnt proteins) was discovered almost four decades ago by Nüsslein-Volhard and Wieschaus. They identified and originally named the gene "wingless" (wg) after a phenotype discovered during their landmark genetic screen in Drosophila for body pattern defects. At around the same time, another researcher named Harold Varmus found that a murine tumor virus activates the mammalian wg homolog, Int-1, which results in tumor...
01:20The JAK-STAT Signaling Pathway
Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as SH2...
01:41Non-Canonical Wnt Signaling Pathways
Wnt is a zygotic effect gene that is expressed during very early embryonic development. It regulates various processes in animals starting from early development through the adult stage, such as organogenesis in the embryo and maintenance of neuronal and blood stem cells. Wnt proteins can induce a wide variety of intracellular pathways depending upon the specific abilities of different Wnt ligands to form a complex with shared and cognate receptors in the presence of different co-receptors. The...