Michel Bouvier: BRET, Biased Agonism, and the Tools That Changed GPCR Pharmacology

G-protein-coupled receptors were once described through a simple model: a lock waiting for a key. Agonists turned them on. Antagonists blocked them. The model was clean, teachable, and wrong in ways that took decades to prove.

Michel Bouvier has spent his career building the tools to show why. From the development of BRET-based biosensors that revealed receptor behavior in living cells, to the discovery of pharmacological chaperones that rescue misfolded receptors from the endoplasmic reticulum, to the experimental frameworks that made biased agonism a credible drug discovery target - his lab has consistently produced technology before the field knew it needed it.

This conversation covers the arc of that career: the personal loss that drew Bouvier toward the sympathetic nervous system, the postdoc in Bob Lefkowitz's lab during the molecular biology revolution in GPCR science, and the foundational question that has guided every receptor his lab has ever studied. Not which receptor - but which question.

ABOUT THE GUEST

Michel Bouvier is CEO of the Institut de Recherches Cliniques de Montreal (IRCM) and Principal Investigator at the Molecular Pharmacology Research Unit, as well as Professor in the Department of Biochemistry and Molecular Medicine at Universite de Montreal.

He completed his PhD under Jacques de Champlain, studying the role of presynaptic adrenergic receptors in hypertension, and his postdoctoral training with Bob Lefkowitz at Duke University, where he was among the first scientists to achieve heterologous GPCR expression in mammalian cells alongside Brad Kobilka, Jeff Benovic, and others.

His lab's contributions include the development of BRET (Bioluminescence Resonance Energy Transfer) technology for studying protein-protein interactions and receptor signaling in living cells, the pharmacological chaperone concept for rescuing misfolded GPCR mutants, and biosensor platforms that helped establish functional selectivity and biased agonism as drug discovery targets.

SCIENTIFIC THEMES OF THE CONVERSATION

• The limits of the binary receptor model and what inverse agonism revealed
  

• BRET technology as a platform for studying GPCR signaling in living cells
  

• Pharmacological chaperones and the concept of rescuing misfolded receptors
  

• Functional selectivity and biased agonism as a framework for next-generation drug discovery
  

• How the tools available define the questions a lab can ask - and the questions that have to wait
  

• The personal and scientific roots of a question-driven research program

KEY INSIGHTS FROM THE CONVERSATION

The question comes before the receptor

Bouvier has never chosen a receptor the way other labs do - as a system to commit to for a career. Every receptor his lab has studied was selected because it was the right model for a question that was already driving the program. That inversion - question first, receptor second - shaped a body of work that spans adrenergic receptors, chemokine receptors, vasopressin receptors, and class C GPCRs without ever being defined by any single one.

Unexpected data is the signal, not the noise

A line Bouvier returns to throughout his career, originally from Julie Axelrod via his PhD mentor Jacques de Champlain: when you get the data you expected, that's fine. When you get data you didn't expect and can rule out artifact - that's when you have something. This isn't just philosophy. It describes the actual origin of BRET, pharmacological chaperones, and the inverse agonism work - each born from a result that didn't fit the prevailing model.

BRET was built in response to a rejection

The technology that would become BRET emerged from a peer-review demand. A high-impact journal accepted the GPCR dimerization data but required evidence in living cells - which didn't exist yet and would take longer than the revision window to develop. Rather than wait, Bouvier's team submitted elsewhere and started building. The proximity assay that resulted, inspired by marine bioluminescence, became one of the most widely used tools in GPCR pharmacology.

Pharmacological chaperones came from a project that looked dead

A PhD student testing the effect of nephrogenic diabetes insipidus mutations on the V2 vasopressin receptor found that none of the mutants reached the plasma membrane. The project appeared finished. In the lab meeting that followed, someone suggested that a lipophilic antagonist might penetrate to the endoplasmic reticulum and stabilize a near-native conformation. Almost everyone dismissed the idea. Bouvier loved it. A call to Sanofi produced a compound from a drawer, the experiment worked, and the pharmacological chaperone concept was born.

Inverse agonism split the room

When Bouvier presented the concept of inverse agonism - compounds that inhibit the spontaneous activity of a constitutively active receptor - to a mixed audience of pharmacologists and chemists, the pharmacologists wanted to call it heresy. The chemists called it allosteric regulation and asked what was new. The divide illustrated something Bouvier has observed repeatedly: mental models, once useful, can become obstacles. The key-and-lock image that helped generations of students understand receptor pharmacology had calcified into a constraint on what the field was willing to see.

Passion is not a soft variable

Bouvier frames this explicitly and without sentimentality: research has periods where it is simply difficult, and passion is what carries a scientist through them. Not talent alone. He is careful to separate the two - invoking the Axelrod anecdote not to diminish intelligence but to make the case that sustained curiosity is the variable most trainable and most often underestimated by advisors and students alike.

EPISODE TIMELINE

Timestamps are AI-generated estimates based on transcript content. Verify against the final edited audio before publishing.

• 00:00 Introduction

• 02:23 Scientific origin - the high school chemistry teacher who made synthesis feel real

• 04:44 A father's death at 39 from hypertension and the path toward receptor pharmacology

• 08:18 Cold-calling Bob Lefkowitz - landing the postdoc that changed the trajectory

• 12:06 The meaning of unexpected data and what it signals about discovery

• 14:49 Arriving at Duke during the GPCR molecular biology revolution

• 17:50 Question-driven research - why Bouvier has never had a favorite receptor

• 20:03 The origin of BRET - dimerization controversy, marine bioluminescence, and a reviewer's demand

• 25:51 Building G-protein biosensors and the team that made it happen

• 27:57 From living-cell tools to drug discovery - baculovirus expression, inverse agonism, and biased agonism

• 34:15 Discovering pharmacological chaperones for V2 vasopressin receptor mutations

• 40:19 Advice for junior scientists and the rewards of discovery

• 43:41 Closing reflections

SELECTED QUOTES

About Dr. Michel Bouvier

Michel Bouvier is a professor of Biochemistry and Molecular Medicine and the CEO of the Institute for Research in Immunology and Cancer (IRIC) at the Université de Montréal.

Following his Ph.D. in Neurological Sciences at the same university in 1985, he completed a post-doctoral fellow at Duke University in the laboratory of Robert Lefkowitz. In 1989, he returned to Montréal as a professor of biochemistry and a scholar of the Medical Research Council of Canada at the Faculty of Medicine of the Université de Montréal.

Since 2001, he holds the Canada Research Chair in Signal Transduction and Molecular Pharmacology. Dr. Bouvier is the author of 300 scientific papers and 15 patents and delivered close to 500 invited conferences. He is a world-renowned expert in the field of cell signaling and GPCRs and made seminal contributions to our understanding of this major class of drug targets. In addition to paradigm shifts including inverse agonism, biased signaling, and pharmacological chaperones, his work on bioluminescence resonance energy transfer (BRET) resulted in the development of screening assays that are now widely used for drug discovery.

His work received more than 30,000 citations yielding an h-index of 95. He has supervised the research work of 75 graduate students and 40 post-doctoral fellows. Michel’s scientific contributions were recognized by the attribution of many awards and distinctions including his election as a fellow of the Royal Society of Canada (2014), the Julie Axelrod award from the American Society of Pharmacology and Exerimental Therapeutics (2017), the Wilder Penfield award from the Quebec Government (2017), the innovation award of ADRIQ (2019) and the 2021 Killam prize form the Canada Council for the Arts.

As some of you may know, Michel was one of my professors at the Universite de Montreal. He was also the head of both my Master’s and Ph.D. thesis committees. I was and am still impressed by Dr. Bouvier’s ability to ask highly relevant questions during meetings. In this episode, you will hear us talk about it.

I spent some time working in Michel’s lab with some of his postdocs and although I was never officially a member of the lab, I am humbled to have been able to work with him and his team and use the tools developed in his lab to better understand GPCR structure/function relationships.

Dr. Michel Bouvier on the web

• Wikipedia

• IRIC

• Bouvier Lab

• Google Scholar

• Pubmed

• ResearchGate

• Twitter

• LinkedIn

• Universite de Montreal- Department of Biochemistry and Molecular Medicine

• Dr. GPCR Ecosystem