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Kathryn Livingston: Allosteric Opioid Modulators and Receptor Signaling Beyond the Membrane

Opioid receptors belong to a class of GPCRs where the pharmacology extends well beyond what equilibrium binding data can show. The first allosteric modulators of opioid receptors were discovered through an academic-industry collaboration and immediately raised a foundational question: without competing for the orthosteric site, how do these compounds actually work? Livingston's PhD research at the University of Michigan addressed this systematically - mapping selectivity, mechanism, and the long-term consequences of modulator exposure on receptor desensitization and tolerance acquisition.

Her postdoc in von Zastrow's lab at UCSF introduced a different framework entirely. Rather than measuring endpoint states, she learned to watch receptors move, internalize, and continue signaling from inside the cell - a finding that challenged the membrane-centric assumption underlying much of classical receptor pharmacology.

The conversation traces the scientific and personal logic behind each transition: from chemistry to pharmacology, from membrane to endosome, from bench to product development. For Livingston, GPCRs were never purely academic - her entry into the field began with a forensic toxicologist father who tested crime scene samples for controlled substances, and a question about why molecules change who we are.

About the Guest

Livingston completed her PhD in pharmacology at the University of Michigan, where she investigated the first allosteric modulators of opioid receptors under Traynor, characterizing their selectivity, binding mechanisms, and effects on acute and chronic receptor signaling. She trained as a postdoctoral fellow in von Zastrow's lab at UCSF, where she worked on beta-2 adrenergic receptor internalization using live-cell imaging approaches that track receptor dynamics in real time. She now works at Gator Bio, where she transitioned from Field Application Scientist - serving as a technical liaison between GPCR researchers and analytical instrumentation - to Product Manager, translating customer research needs into commercial tools.

Scientific Themes of the Conversation

Allosteric modulation of opioid receptors - mechanism, selectivity, and therapeutic rationale
Receptor internalization and post-endocytic signaling as a paradigm shift in GPCR pharmacology
Assay design as an epistemic constraint on pharmacological interpretation
Equilibrium vs. dynamic frameworks for studying receptor biology
The Field Application Scientist as a career model for GPCR-trained scientists
The structural complementarity of academic and industry research in drug discovery

Key Insights from the Conversation

1. Allosteric opioid modulators bypass the orthosteric site entirely

Rather than competing with morphine or endogenous opioids at the binding pocket, allosteric modulators act at a distinct site on the receptor. Livingston's PhD project was among the first to characterize how these compounds operate - mapping whether activity is receptor-dependent, whether they shift affinity or efficacy, and whether effects persist through desensitization and tolerance. The therapeutic logic is that decoupling from the orthosteric site might preserve pain relief while altering the signaling profiles responsible for side effects.

2. Internalized receptors don't stop working

The membrane-centric view of receptor pharmacology assumes signaling ends when a receptor is endocytosed. Von Zastrow's lab challenged this directly, demonstrating that GPCRs continue to generate signals after they leave the cell surface. For Livingston, encountering this finding after a PhD grounded in equilibrium binding required a genuine conceptual reset - the receptor she had been mapping was not anchored to the membrane in the way her training had assumed.

3. An assay measures a specific thing - not the biology you assume it measures

One of Livingston's most consistently held principles: understanding exactly what your assay is measuring is not optional. A readout that captures a downstream marker, a surrogate signal, or a population average can yield clean data while systematically pointing in the wrong direction. Misinterpreting assay specificity is, in her view, one of the most consequential and underacknowledged sources of error in pharmacological research.

4. Live-cell imaging makes the dynamic pharmacology of GPCRs visible

Where equilibrium assays capture endpoint states, live-cell microscopy reveals what happens between them. During her postdoc, Livingston transitioned from pulling numbers off instruments to watching receptors traffic, cluster, and internalize in real time. She describes the shift as both technically disorienting and visually striking - a different relationship to data than any endpoint assay can produce.

5. Academia and industry are structurally complementary - not competing versions of the same thing

Academia can sustain a 15-year investigation of a single receptor question. Industry can screen tens of millions of compounds in the time it takes to write a grant. Livingston argues these structural constraints make the two sectors dependent on each other - and notes that her PhD emerged directly from an academic-industry collaboration that would not have produced the allosteric modulators without both sides present.

6. The Field Application Scientist role is one of the least-known best fits for GPCR-trained scientists

The FAS role combines technical depth, customer-facing science, and teaching - a combination Livingston describes as a natural extension of what she valued most in training. The role is rarely discussed in academic career advising, yet it draws directly on GPCR pharmacology skills: deep assay knowledge, the ability to troubleshoot complex data, and fluency across multiple experimental systems.

Episode Timeline

Timestamps are AI-generated based on transcript analysis and may not reflect exact chapter breaks in the final audio or video. Use as a navigational guide.

00:00 Introduction and ecosystem announcements
02:15 From inorganic chemistry to GPCR pharmacology
03:17 The origin story - forensic toxicology, mental disorders, and GPCRs
06:58 PhD research: first allosteric modulators of opioid receptors
11:58 Know your assay - and why getting it wrong costs more than data
12:36 Choosing von Zastrow's lab and the internalization paradigm shift
14:17 How to choose a postdoc with no trial period
19:07 Beta-2 adrenergic receptors and live-cell imaging at UCSF
22:02 The moment academia stopped making sense
30:54 From Field Application Scientist to Product Manager
38:58 What both roles look like day-to-day
39:28 Three steps for PhDs and postdocs considering industry

Selected Quotes

"Instead of directly targeting the receptor like morphine or buprenorphine, we target allosterically. We enhance your endogenous tone, we cause pain relief, maybe we mitigate some of these side effects."

"To go to Mark's lab where everything is dynamic, everything is moving - this is a live cell where pieces are internalizing, moving - and then to flip it on its head again and say the receptor at the surface might not be the center of the world."

"You have to know what your assay is actually measuring. Because you can get this data and you interpret it one way, but if you don't know the nuances, the very intricacies about your assay - you don't actually know what the specificity of the thing you're measuring is - then you can interpret it in a really wrong way."

"In industry, you can't spend 15 years trying to solve one problem. There's no way. But in academia, you also can't screen 30 million cell lines in an afternoon. They're completely complementary."

About Dr. Kathryn E Livingston

Dr. Kathryn E Livingston is currently a Product Manager at Gator Bio, a biotechnology company providing solutions to researchers studying protein-protein interactions. Kathryn obtained her BS in Chemistry from Carnegie Mellon University and went on to receive a Ph.D. in Pharmacology at the University of Michigan. Working under the supervision of Dr. John Traynor,

Kathryn worked to develop and understand first-in-class allosteric modulators of opioid receptors. Research into their mechanism of action in purified systems formed the base of her thesis work. Following this, Kathryn did a post-doctoral fellowship at UCSF in the laboratory of Dr. Mark von Zastrow. There she researched the beta-2 adrenergic receptor and developed assays to investigate real-time activity in intact cellular systems. Kathryn’s passion is developing solutions to problems in whatever form is most efficient: novel instrumentation, novel methods, or novel communication.

Dr. Kathryn E Livingston on the web