Related Experiment Video

Updated: Aug 4, 2026

RhoC GTPase Activation Assay
09:58

RhoC GTPase Activation Assay

Published on: August 23, 2010

Oncogenic Ras leads to Rho activation by activating the mitogen-activated protein kinase pathway and decreasing

Jeffrey C Chen1, Shunhui Zhuang, Tony H Nguyen

  • 1Department of Medicine and Cancer Center, University of California, San Diego, La Jolla, California 92093-0652, USA.

The Journal of Biological Chemistry
|November 14, 2002
PubMed

Insights

Oncogenic Ras activates RhoA signaling, crucial for cell transformation. This study reveals Ras increases RhoA activity by altering p190 Rho-GAP localization via the Raf/MEK/ERK pathway.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Cancer Research

Background:

  • Oncogenic Ras is known to require Rho family proteins, including RhoA, for cellular transformation.
  • The precise mechanisms by which oncogenic Ras influences RhoA activity remain largely uncharacterized.

Purpose of the Study:

  • To investigate the effect of oncogenic Ras on RhoA activity in NIH 3T3 cells.
  • To elucidate the signaling pathway and molecular mechanisms linking Ras to RhoA activation.

Main Methods:

  • Utilized NIH 3T3 cells stably transfected with inducible H-Ras(V12) or transiently expressing activated H-Ras.
  • Employed a novel enzymatic method to quantify GTP-bound Rho.
  • Assessed plasma membrane binding of RhoA, p21(WAF1/CIP1) promoter activity, and p190 Rho-GAP activity and localization.

Main Results:

  • Oncogenic Ras expression led to an approximate 2-fold increase in RhoA activity.
  • Increased RhoA activity correlated with enhanced plasma membrane binding and reduced p21(WAF1/CIP1) promoter activity.
  • Ras-induced RhoA activation was linked to decreased cytosolic p190 Rho-GAP activity and its translocation to a detergent-insoluble cytoskeletal fraction.

Conclusions:

  • Oncogenic Ras activates RhoA in NIH 3T3 cells through the Raf/MEK/ERK signaling cascade.
  • This activation involves the reduction of cytosolic p190 Rho-GAP activity and a change in its subcellular localization.
  • The findings identify a novel mechanism for Ras-mediated RhoA regulation impacting cellular transformation.

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

Intracellular Phosphoflow Cytometry of Acute Myeloid Leukemia Patient-Derived Xenotransplants07:38

Intracellular Phosphoflow Cytometry of Acute Myeloid Leukemia Patient-Derived Xenotransplants

Published on: June 6, 2025

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...
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...
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...