Comprehensive Profiling of GAT100 Confirms It as a Superior CB1 Allosteric Modulator for Drug Development
Extensive functional profiling of the covalent CB1 allosteric probe GAT100 across multiple signaling pathways confirmed it as a more potent and cleaner negative allosteric modulator than existing compounds, with critical structural insights.
Quick Facts
What This Study Found
Building on the initial discovery of GAT100 (RTHC-01201), this study comprehensively characterized its effects across an array of downstream signaling pathways.
GAT100 functioned as a negative allosteric modulator of the orthosteric agonist CP55,940 and the endocannabinoids 2-AG and anandamide across multiple readouts: beta-arrestin1 recruitment, PLCbeta3 and ERK1/2 phosphorylation, cAMP accumulation, and CB1 receptor internalization.
Critically, GAT100 was more potent and effective than both Org27569 and PSNCBAM-1 (the two most-studied CB1 allosteric modulators) in every assay tested. It also lacked the inverse agonism associated with those earlier compounds, a significant advantage for drug development.
Computational docking studies identified C7.38(382) as a key structural feature of GAT100's binding to the allosteric site, providing critical information for designing next-generation allosteric drugs.
Key Numbers
GAT100 tested across 5+ signaling pathways. More potent and efficacious than Org27569 and PSNCBAM-1 in all assays. No inverse agonism. C7.38(382) identified as critical binding residue. Active in both overexpression and endogenous CB1 expression systems.
How They Did This
Multi-assay functional profiling in HEK293A cells overexpressing CB1R and in Neuro2a and STHdhQ7/Q7 cells endogenously expressing CB1R. Assessed beta-arrestin1 recruitment, PLCbeta3 phosphorylation, ERK1/2 phosphorylation, cAMP accumulation, and receptor internalization. Computational docking studies identified key binding residues.
Why This Research Matters
This comprehensive profiling establishes GAT100 as the gold-standard tool for studying CB1 allosteric modulation and provides the detailed signaling data needed to guide drug design. The identification of the key binding residue is a breakthrough for rational drug development.
The Bigger Picture
This work represents a critical step from basic discovery toward translational application. By thoroughly characterizing GAT100's signaling profile and identifying structural determinants, the study provides the roadmap for engineering the next generation of CB1 allosteric drugs.
What This Study Doesn't Tell Us
All data are from cell-based systems. In vivo validation is needed. The covalent nature of GAT100 limits its therapeutic potential but enhances its value as a research tool. Endogenous expression systems used different cell types that may not fully reflect neuronal CB1 biology.
Questions This Raises
- ?Can reversible analogs of GAT100 be designed that retain its improved pharmacological profile?
- ?Will the C7.38(382) binding site be confirmed by crystallography or cryo-EM?
- ?How does allosteric modulation of CB1 affect behavior in animal models?
Trust & Context
- Key Stat:
- GAT100 outperformed all existing CB1 allosteric modulators across every assay
- Evidence Grade:
- Thorough in vitro characterization across multiple cell systems and signaling pathways, with computational structural insights. No in vivo data.
- Study Age:
- Published in 2016. GAT100 has become a widely used research tool in cannabinoid pharmacology.
- Original Title:
- Mapping Cannabinoid 1 Receptor Allosteric Site(s): Critical Molecular Determinant and Signaling Profile of GAT100, a Novel, Potent, and Irreversibly Binding Probe.
- Published In:
- ACS chemical neuroscience, 7(6), 776-98 (2016)
- Authors:
- Laprairie, Robert B(15), Kulkarni, Abhijit R(2), Kulkarni, Pushkar M(3), Hurst, Dow P, Lynch, Diane, Reggio, Patricia H, Janero, David R, Pertwee, Roger G, Stevenson, Lesley A, Kelly, Melanie E M, Denovan-Wright, Eileen M, Thakur, Ganesh A
- Database ID:
- RTHC-01204
Evidence Hierarchy
Tests effects in animals (usually mice or rats), not humans.
What do these levels mean? →Frequently Asked Questions
What makes GAT100 better than previous CB1 allosteric modulators?
GAT100 is more potent, more effective, and lacks the unwanted inverse agonism of Org27569 and PSNCBAM-1. It works consistently across multiple signaling pathways and cell types.
How does this help develop new medicines?
By identifying exactly how GAT100 binds to the CB1 allosteric site (including the key residue C7.38), researchers can design new drugs that precisely modulate CB1 activity for therapeutic purposes.
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Cite This Study
https://rethinkthc.com/research/RTHC-01204APA
Laprairie, Robert B; Kulkarni, Abhijit R; Kulkarni, Pushkar M; Hurst, Dow P; Lynch, Diane; Reggio, Patricia H; Janero, David R; Pertwee, Roger G; Stevenson, Lesley A; Kelly, Melanie E M; Denovan-Wright, Eileen M; Thakur, Ganesh A. (2016). Mapping Cannabinoid 1 Receptor Allosteric Site(s): Critical Molecular Determinant and Signaling Profile of GAT100, a Novel, Potent, and Irreversibly Binding Probe.. ACS chemical neuroscience, 7(6), 776-98. https://doi.org/10.1021/acschemneuro.6b00041
MLA
Laprairie, Robert B, et al. "Mapping Cannabinoid 1 Receptor Allosteric Site(s): Critical Molecular Determinant and Signaling Profile of GAT100, a Novel, Potent, and Irreversibly Binding Probe.." ACS chemical neuroscience, 2016. https://doi.org/10.1021/acschemneuro.6b00041
RethinkTHC
RethinkTHC Research Database. "Mapping Cannabinoid 1 Receptor Allosteric Site(s): Critical ..." RTHC-01204. Retrieved from https://rethinkthc.com/research/laprairie-2016-mapping-cannabinoid-1-receptor
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.