Related Experiment Video
Updated: Jul 8, 2026
A High-content Imaging Workflow to Study Grb2 Signaling Complexes by Expression Cloning
Published on: October 30, 2012
Development of binding assays for the SH2 domain of Grb7 and Grb2 using fluorescence polarization
Jean-Philippe Luzy1, Huixiong Chen, Brunilde Gril
1INSERM U648, Laboratoire de Pharmacochimie Moléculaire et Cellulaire, UFR Biomédicale, Université Paris Descartes, Paris, France.
Abstract:
Adaptor proteins Grb7 and Grb2 have been implicated as being 2 potential therapeutic targets in several human cancers, especially those that overexpress ErbB2. These 2 proteins contain both a SH2 domain (Src homology 2) that binds to phosphorylated tyrosine residues contained within ErbB2 and other specific protein targets. Two assays based on enzyme-linked immunosorbent assay and fluorescence polarization methods have been developed and validated to find and rank inhibitors for both proteins binding to the pY(1139). Fluorescence polarization assays allowed the authors to determine quickly and reproducibly affinities of peptides from low nanomolar to high micromolar range and to compare them directly for Grb7 and Grb2. As a result, the assays have identified a known peptidomimetic Grb2 SH2 inhibitor (mAZ-pTyr-(alphaMe)pTyr-Asn-NH(2)) that exhibits the most potent affinity for the Grb7 SH2 domain described to date.
Insights
New assays identify potent inhibitors for Grb7 and Grb2 (Src homology 2) proteins, crucial targets in ErbB2-overexpressing cancers. A known Grb2 inhibitor shows unprecedented affinity for Grb7, offering new therapeutic avenues.
Area of Science:
- Biochemistry
- Molecular Biology
- Oncology
Background:
- Adaptor proteins Grb7 and Grb2 are implicated as therapeutic targets in human cancers, particularly those overexpressing ErbB2.
- Both proteins possess a SH2 (Src homology 2) domain that binds to phosphorylated tyrosine residues on ErbB2 and other targets.
Purpose of the Study:
- To develop and validate assays for identifying and ranking inhibitors of Grb7 and Grb2 SH2 domain binding to pY(1139).
- To compare the binding affinities of potential inhibitors for Grb7 and Grb2.
Main Methods:
- Development and validation of two assays: enzyme-linked immunosorbent assay (ELISA) and fluorescence polarization (FP).
- Utilized FP assays for rapid and reproducible determination of peptide affinities, ranging from nanomolar to micromolar concentrations.
- Direct comparison of inhibitor affinities for Grb7 and Grb2 SH2 domains.
Main Results:
- Successfully developed and validated ELISA and FP assays for Grb7 and Grb2 inhibitor screening.
- FP assays enabled efficient determination and comparison of binding affinities across a wide concentration range.
- Identified a known Grb2 SH2 inhibitor, mAZ-pTyr-(alphaMe)pTyr-Asn-NH(2), as the most potent Grb7 SH2 domain binder reported to date.
Conclusions:
- The developed assays are effective tools for discovering and ranking inhibitors of Grb7 and Grb2 SH2 domains.
- The findings highlight a promising peptidomimetic inhibitor with high affinity for Grb7, suggesting its potential in cancer therapy.
- This research provides a foundation for developing targeted therapies against ErbB2-driven cancers by inhibiting Grb7 and Grb2.
