Related Experiment Video

Updated: Oct 2, 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

Ras-mediated cleavage of a GTP analogue by a novel mechanism

R Gail1, B Costisella, M R Ahmadian

  • 1Max-Planck-Institut für molekulare Physiologie, Abteilung Strukturelle Biologie, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.

Chembiochem : a European Journal of Chemical Biology
|February 6, 2002
PubMed

Insights

Oncogenic Ras mutations impair GTP hydrolysis. A novel GTP analogue, DABP-GTP, enables inactivation via a unique mechanism, offering potential for new anti-Ras cancer drugs.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Oncology

Background:

  • Ras proteins are key regulators of cell signaling, growth, and differentiation.
  • Mutations in Ras genes are common in human cancers, leading to uncontrolled cell proliferation.
  • Oncogenic Ras mutations disrupt the normal GTPase activity, locking Ras in an active state.

Purpose of the Study:

  • To investigate the mechanism of action of a novel GTP analogue, 3,4-diaminobenzophenone(DABP)-phosphoramidate-GTP.
  • To determine if DABP-GTP can inactivate both wild-type and oncogenic Ras proteins.
  • To explore the potential of DABP-GTP as a therapeutic agent against Ras-driven cancers.

Main Methods:

  • High-Performance Liquid Chromatography (HPLC)
  • Mass Spectrometry (MS)
  • Nuclear Magnetic Resonance (NMR) Spectroscopy

Main Results:

  • DABP-GTP facilitates the transition of Ras to its inactive GDP-bound form in both wild-type and oncogenic Ras.
  • The DABP-GTPase reaction mechanism differs significantly from physiological GTP hydrolysis.
  • The reaction involves nucleophilic attack by the analogue's amino group on the gamma-phosphate, forming a stable cyclic diamidate product, rather than water.

Conclusions:

  • The unique mechanism of DABP-GTP offers a novel approach to inhibiting Ras signaling.
  • These findings provide a basis for developing new anti-Ras drugs targeting GTPase activity.
  • Targeting Ras with novel analogues like DABP-GTP holds promise for cancer therapy.

More Related Videos

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells10:27

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

Published on: March 9, 2012

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

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:
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...
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...
Rab Proteins01:14

Rab Proteins

Rab proteins constitute the largest family of monomeric GTPases, of which 70 members are present in humans. Rab proteins and their effectors regulate consecutive stages of vesicle transport such as vesicle transport, docking, and fusion to the correct recipient membrane.
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
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.
GPCR Desensitization01:12

GPCR Desensitization

G protein-coupled receptor (GPCR) signaling plays a crucial role in cell functioning. GPCR desensitization is an equally essential process. It allows cells to respond to changing environments and regain sensitivity to new stimuli while preventing unnecessary stimulation when no longer needed. Prolonged exposure to stimuli leads to GPCR desensitization. It involves blocking the receptors from binding and activating additional G proteins. This inhibits activation of downstream effectors, thereby...