Related Experiment Video

Updated: May 22, 2026

Bioluminescence Resonance Energy Transfer (BRET)-Based Assay for Measuring Interactions of CRAF with 14-3-3 Proteins in Live Cells
06:44

Bioluminescence Resonance Energy Transfer (BRET)-Based Assay for Measuring Interactions of CRAF with 14-3-3 Proteins in Live Cells

Published on: March 1, 2024

The tumor suppressor DiRas3 forms a complex with H-Ras and C-RAF proteins and regulates localization, dimerization,

Angela Baljuls1, Matthias Beck, Ayla Oenel

  • 1Theodor Boveri Institute of Bioscience, Department of Microbiology, University of Wuerzburg, 97074 Wuerzburg, Germany. angela_baljuls@gmx.de

The Journal of Biological Chemistry
|May 19, 2012
PubMed

Insights

The tumor suppressor DiRas3 interacts with H-Ras, forming a complex that inhibits cancer cell growth. This discovery clarifies how DiRas3 impacts Ras/MAPK signaling, offering new therapeutic targets for breast and ovarian cancers.

Area of Science:

  • Molecular Biology
  • Oncology
  • Cell Signaling

Background:

  • The maternally imprinted Ras-related tumor suppressor gene DiRas3 is frequently lost or downregulated in ovarian and breast cancers.
  • DiRas3 exhibits anti-tumorigenic effects by inhibiting proliferation, motility, invasion, and inducing apoptosis and autophagy.
  • Re-expression of DiRas3 disrupts Ras/MAPK and PI3K signaling, but its precise mechanism of interference with Ras/RAF/MEK/ERK pathway remains unclear.

Purpose of the Study:

  • To elucidate the molecular mechanism by which DiRas3 interferes with the Ras/RAF/MEK/ERK signal transduction pathway.
  • To investigate the interaction between DiRas3 and the H-Ras oncogene and its downstream effects on signaling.

Main Methods:

  • Co-immunoprecipitation assays to detect protein-protein interactions.
  • Western blotting to analyze protein levels and activation states.
  • Analysis of multimeric complex formation and its stability.

Main Results:

  • DiRas3 directly associates with the H-Ras oncogene, an interaction strengthened upon H-Ras activation.
  • The active H-Ras-DiRas3 complex facilitates H-Ras binding to its effector protein C-RAF.
  • A stable multimeric complex of DiRas3, C-RAF, and active H-Ras is formed, leading to C-RAF recruitment to the membrane skeleton, suppressed C-RAF/B-RAF heterodimerization, and inhibited C-RAF kinase activity.

Conclusions:

  • DiRas3 acts as a negative regulator of the Ras/MAPK pathway by forming a stable complex with H-Ras and C-RAF.
  • This interaction leads to the inhibition of C-RAF kinase activity, providing a mechanistic explanation for DiRas3's tumor-suppressive function.
  • Understanding this interaction opens avenues for developing targeted therapies for cancers with altered DiRas3 and H-Ras signaling.

More Related Videos

Characterize Disease-related Mutants of RAF Family Kinases by Using a Set of Practical and Feasible Methods07:49

Characterize Disease-related Mutants of RAF Family Kinases by Using a Set of Practical and Feasible Methods

Published on: July 17, 2019

Generation of High-Throughput Three-Dimensional Tumor Spheroids for Drug Screening05:54

Generation of High-Throughput Three-Dimensional Tumor Spheroids for Drug Screening

Published on: September 5, 2018

Related Concept Videos

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...
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...
PI3K/mTOR/AKT Signaling Pathway01:22

PI3K/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...
mTOR Signaling and Cancer Progression03:03

mTOR Signaling and Cancer Progression

The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
Abnormal Proliferation02:23

Abnormal Proliferation

Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...