Related Experiment Video

Updated: Aug 8, 2026

Comparing the Affinity of GTPase-binding Proteins using Competition Assays
10:37

Comparing the Affinity of GTPase-binding Proteins using Competition Assays

Published on: October 8, 2015

Interactions between p21ras proteins and their GTPase activating proteins

P Polakis1, F McCormick

  • 1Cetus Corporation, Emeryville, California 94608.

Cancer Surveys
|January 1, 1992
PubMed

Insights

Two proteins, GAP and NF1 gene product, regulate p21ras GTPase activity by interacting with ras p21. Ki-rev1 gene product (p21rap1) may suppress oncogene transformation by competing for GAP binding.

Area of Science:

  • Molecular Biology
  • Cell Signaling
  • Oncology

Background:

  • p21ras GTPase activity is crucial for cellular signaling pathways.
  • Understanding proteins that regulate p21ras is key to deciphering cell growth and disease.
  • Ras signaling is implicated in various cancers and genetic disorders like NF1.

Purpose of the Study:

  • To identify and characterize proteins that regulate p21ras GTPase activity.
  • To elucidate the interaction mechanisms between regulatory proteins and ras p21.
  • To investigate the role of these interactions in cellular transformation and disease.

Main Methods:

  • Protein-protein interaction studies to identify binding partners of ras p21.
  • Analysis of protein domains involved in signaling complex formation.
  • Investigating the functional consequences of protein interactions on GTPase activity and cellular transformation.

Main Results:

  • Identified two key regulators of p21ras: GAP and the NF1 gene product.
  • GAP interacts with receptor tyrosine kinases, linking them to p21ras signaling.
  • The NF1 gene product connects p21ras to other signaling pathways relevant to NF1 disease.
  • Ki-rev1 gene product (p21rap1) competes with p21ras for GAP binding, potentially suppressing oncogenic transformation.

Conclusions:

  • GAP and the NF1 gene product are critical regulators of p21ras function.
  • These interactions provide direct links between diverse signaling pathways and p21ras.
  • Ki-rev1's ability to suppress ras oncogenes may be mediated by competitive binding to GAP.

More Related Videos

Detection of Small GTPase Prenylation and GTP Binding Using Membrane Fractionation and GTPase-linked Immunosorbent Assay13:51

Detection of Small GTPase Prenylation and GTP Binding Using Membrane Fractionation and GTPase-linked Immunosorbent Assay

Published on: November 11, 2018

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

Related Concept Videos

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...
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...
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...
Interactions Between Signaling Pathways01:19

Interactions Between Signaling Pathways

Signaling cascades usually lack linearity. Multiple pathways interact and regulate one another, allowing cells to integrate and respond to diverse environmental stimuli.
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
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:
Activation and Inactivation of G Proteins01:22

Activation and Inactivation of G Proteins

Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high affinity and are together...