Related Experiment Video

Updated: May 10, 2026

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells
10:27

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells

Published on: March 9, 2012

The small GTPase RALA controls c-Jun N-terminal kinase-mediated FOXO activation by regulation of a JIP1 scaffold

Maaike C W van den Berg1, Inkie J A van Gogh, Alida M M Smits

  • 1Molecular Cancer Research, University Medical Center Utrecht, Utrecht, 3584 CG, The Netherlands.

The Journal of Biological Chemistry
|June 18, 2013
PubMed

Insights

Cellular stress activates FOXO transcription factors via JNK signaling. This study identifies RALA and JIP1 as key mediators in the ROS-induced JNK-dependent FOXO pathway, conserved in C. elegans.

Area of Science:

  • Molecular Biology
  • Cellular Stress Response
  • Genetics

Background:

  • FOXO transcription factors act as tumor suppressors and influence lifespan.
  • Cellular stress, particularly oxidative stress from reactive oxygen species (ROS), activates FOXOs via JNK-mediated phosphorylation.
  • JNK regulation of FOXO is an evolutionarily conserved process.

Purpose of the Study:

  • To elucidate the specific pathway mediating ROS-induced, JNK-dependent FOXO regulation.
  • To identify novel components involved in this stress response pathway.

Main Methods:

  • Investigated the role of RLF (RalGDS-like factor), RALA, and JIP1 (C-Jun-amino-terminal-interacting protein 1) in ROS-induced signaling.
  • Utilized biochemical assays to study protein complex formation and activation.
  • Employed C. elegans models to confirm evolutionary conservation of the pathway.

Main Results:

  • Identified RLF as an exchange factor activating RALA in response to increased ROS.
  • Demonstrated that RLF, in complex with JIP1 and JNK, facilitates the assembly and activation of MLK3, MKK4, and JNK onto the JIP1 scaffold.
  • Showcased conserved regulation of FOXO by RALA and JIP1 in C. elegans, where depletion of ral-1 or jip-1 hindered heat shock-induced DAF16 nuclear translocation.

Conclusions:

  • The pathway involving RLF, RALA, and JIP1 is crucial for ROS-induced JNK-dependent FOXO activation.
  • This regulatory mechanism is conserved across species, highlighting its fundamental importance in stress response.
  • Findings provide new insights into the molecular underpinnings of cellular stress and FOXO function.
Keywords:
C. elegansMAP Kinases (MAPKs)Reactive Oxygen Species (ROS)Scaffold ProteinsSignal TransductionSmall GTPasesTranscription Factors

More Related Videos

Affinity Precipitation of Active Rho-GEFs Using a GST-tagged Mutant Rho Protein (GST-RhoA(G17A)) from Epithelial Cell Lysates11:28

Affinity Precipitation of Active Rho-GEFs Using a GST-tagged Mutant Rho Protein (GST-RhoA(G17A)) from Epithelial Cell Lysates

Published on: March 31, 2012

RhoC GTPase Activation Assay09:58

RhoC GTPase Activation Assay

Published on: August 22, 2010

Related Concept Videos

Small GTPases - Ras and Rho01:24

Small 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:
MAPK Signaling Cascades01:07

MAPK 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...
The JAK-STAT Signaling Pathway01:20

The 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...
The Ras Gene02:38

The Ras Gene

The Ras-gene-encoded proteins are regulators of signaling pathways controlling cell proliferation, differentiation, or cell survival. The Ras-gene family in humans constitutes three primary members—the HRas, NRas, and KRas. These genes code for four functionally distinct yet closely related proteins—the HRas, NRas, KRas4A, and KRas4B. The involvement of mutant Ras genes in human cancer was first discovered in 1982 and is among the most common causes of human tumorigenesis.
Ras is a superfamily...
Rab Cascades01:25

Rab Cascades

Rab GTPases act in a regulated cascade during membrane fusion, helping the lipid bilayers mix. The Rab family of proteins are active when bound to GTP, and inactive when bound to GDP. Hence, they act as guanine nucleotide-dependent molecular switches. Rab-GTP recognizes and binds to long or short-range tethering proteins to capture the target vesicle. These tethers coordinate with SNAREs on the vesicle and the target membrane to assemble the trans SNARE complex that locks the mixing bilayers.
GTPases and their Regulation02:14

GTPases and their Regulation

Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒  small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...