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Cell-permeable high-affinity tracers for Gq proteins provide structural insights, reveal distinct binding kinetics

Markus Kuschak1, Vigneshwaran Namasivayam1, Muhammad Rafehi1

  • 1PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, Bonn, Germany.

British Journal of Pharmacology
|December 28, 2019
PubMed
Abstract

Insights

Researchers developed novel high-affinity probes for Gq proteins, enabling accurate quantification and the discovery of new Gq inhibitors for potential therapeutic applications in cancer and inflammatory diseases.

Area of Science:

  • Cellular signaling and molecular biology
  • Pharmacology and drug discovery
  • Oncology and disease research

Background:

  • G proteins act as intracellular signal transducers, with Gq subtypes linked to oncogenesis and upregulated in cancer.
  • Gq protein inhibition presents a promising therapeutic strategy, yet lacks specific diagnostic tools and drugs.
  • The need for precise tools to study Gq protein function in disease is critical.

Purpose of the Study:

  • To develop high-affinity, cell-permeable probes for specific labeling and quantification of Gq proteins.
  • To utilize these probes in a high-throughput assay for discovering novel Gq protein inhibitors.
  • To investigate the pharmacological differences between Gq inhibitors FR900359 (FR) and YM-254890 (YM).

Main Methods:

  • Development of 3H-labeled, high-affinity probes based on macrocyclic depsipeptides FR900359 and YM-254890.
  • Utilizing CRISPR/Cas9 Gαq-knockout cells to assess probe specificity for Gq protein subtypes.
  • Employing a high-throughput binding assay to identify novel Gq inhibitors and computational studies to analyze binding kinetics.

Main Results:

  • The developed probes (FR and YM) exhibit low nanomolar affinity for Gαq, Gα11, and Gα14, but not Gα15.
  • FR and YM show distinct dissociation kinetics, suggesting different biological impacts.
  • A high-throughput assay identified novel Gq inhibitors that suppressed Gq signaling and promoted adipocyte differentiation.

Conclusions:

  • Despite structural similarities, FR and YM are pharmacologically distinct Gq protein inhibitors.
  • The developed probes and assays represent versatile tools for advancing G protein research.
  • These findings pave the way for new diagnostic and therapeutic strategies targeting Gq proteins in disease.

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