Related Experiment Video

Updated: Jul 30, 2026

Detection of Small GTPase Prenylation and GTP Binding Using Membrane Fractionation and GTPase-linked Immunosorbent Assay
13:51

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

Published on: November 11, 2018

Binding of transforming protein, P47gag-crk, to a broad range of phosphotyrosine-containing proteins

M Matsuda1, B J Mayer, Y Fukui

  • 1Rockefeller University, New York, NY 10021.

Science (New York, N.Y.)
|June 22, 1990
PubMed

Insights

The P47gag-crk oncoprotein elevates phosphotyrosine in cells and interacts with tyrosine kinases. Its SH2 and SH3 domains mediate phosphotyrosine-dependent protein binding, crucial for signal transduction.

Area of Science:

  • Molecular Biology
  • Oncology
  • Cellular Signaling

Background:

  • The CT10 virus oncogene product, P47gag-crk, is implicated in cellular transformation.
  • P47gag-crk possesses SH2 and SH3 domains, common in signal transduction proteins like tyrosine kinases.

Purpose of the Study:

  • To investigate the role of P47gag-crk in phosphotyrosine elevation and protein interactions within transformed cells.
  • To determine the mechanism by which P47gag-crk regulates protein binding via its SH2 and SH3 domains.

Main Methods:

  • In vitro binding assays using P47gag-crk and phosphotyrosine-containing proteins.
  • Analysis of protein interactions in cells transformed by CT10 virus and oncogenic tyrosine kinases.
  • Assessment of the effect of protein dephosphorylation on P47gag-crk association.

Main Results:

  • P47gag-crk increases phosphotyrosine levels in transformed cells, despite lacking intrinsic kinase activity.
  • P47gag-crk demonstrated in vitro binding to phosphotyrosine-containing proteins from various transformed cell types.
  • The interaction between P47gag-crk and p60v-src was disrupted upon p60v-src dephosphorylation.

Conclusions:

  • The SH2 and SH3 domains of P47gag-crk are critical for mediating protein interactions.
  • These interactions are regulated in a phosphotyrosine-dependent manner, highlighting a key mechanism in oncogenic signaling.

More Related Videos

Co-immunoprecipitation Assay for Studying Functional Interactions Between Receptors and Enzymes09:40

Co-immunoprecipitation Assay for Studying Functional Interactions Between Receptors and Enzymes

Published on: September 28, 2018

Assessing Cellular Target Engagement by SHP2 (PTPN11) Phosphatase Inhibitors08:45

Assessing Cellular Target Engagement by SHP2 (PTPN11) Phosphatase Inhibitors

Published on: July 17, 2020

Related Concept Videos

Enzyme-linked Receptors01:00

Enzyme-linked Receptors

Enzyme-linked receptors are proteins that act as both receptor and enzyme, activating multiple intracellular signals. This is a large group of receptors that include the receptor tyrosine kinase (RTK) family. Many growth factors and hormones bind to and activate the RTKs.
Neurotrophin (NT) receptors are a family of RTKs, including trkA, trkB, and trkC (tropomyosin-related kinase) receptors. TrkA is specific for nerve growth factor (NGF), neurotrophin-6, and neurotrophin-7. TrkB binds...
Assembly of Signaling Complexes01:30

Assembly of Signaling Complexes

Multiprotein signaling complexes are formed in a dynamic process involving protein-protein interactions at the cytoplasmic domain of transmembrane receptors or enzymatic and non-enzymatic proteins associated with the receptor. These complexes ensure the activation and propagation of intracellular signals that regulate cell functions.
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
Amplifying Signals via Enzymatic Cascade01:22

Amplifying Signals via Enzymatic Cascade

When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...
Receptor Tyrosine Kinases01:26

Receptor Tyrosine Kinases

Receptor tyrosine kinases or RTKs are membrane-bound receptors that phosphorylate specific tyrosine on protein substrates. RTKs regulate cellular growth, differentiation, survival, and migration. They contain an extracellular ligand binding domain, a transmembrane domain, and a cytosolic tail with intrinsic kinase activity. Several extracellular signaling molecules activate RTKs in one or more ways and relay the signal downstream. Ligands such as platelet-derived growth factor (PDGF) or...
TGF - β Signaling Pathway01:16

TGF - β Signaling Pathway

The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors are of three kinds RI, RII, and RIII. The RI...
Transducer Mechanism: Enzyme-Linked Receptors01:27

Transducer Mechanism: Enzyme-Linked Receptors

Enzyme-linked receptors are cell-surface receptors acting as an enzyme or associating with an enzyme intracellularly. They make excellent drug targets. Drugs can bind to the extracellular ligand-binding domain or directly affect their enzymatic domain and alter their activity.
Major types that are helpful drug targets include: