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Watch Episode 166 When’s the last time you argued in the lab about injecting GTPγS? Four hundred plates of assays, concentration-response curves, and mutagenesis screens are standard. _____________ Keyword Cloud: GPCR scientist network, GPCR training program, mentorship in science, GTPγS assay, lab culture

discovery, mu-opioid receptor, positive allosteric modulators, GPCR training program, GPCR online course, GTPγS assay, chronic pain

Thus we propose the use of fluorescent probes in GPCR screening assays due to their numerous advantages The advantages of Fluorescent Probes in GPCR assays over other methods Fluorescent ligands are made by receptors, tracking of their internalization and are also safer alternatives to radioligand binding assays The traditional binding assays for GPCRs use radioligands, whose limitations, especially safety concerns common starting point for employing fluorescent probes in GPCR assays.

Radioligands have been used to study GPCRs for decades, but with the advances in the fluorescence field, assays They are ligands labeled with radioactive isotopes which can be used in binding assays to quantify other Fluorescent Probes: Differences in Binding Assays Fluorescent ligands are a type of fluorescent probes that offer an alternative to radioligands in binding assays. GPCR-radioligand binding assays.

Many pharmacology experiments produce beautifully clean assay curves. The harder question is what those assay signals actually predict biologically. Drug discovery programs rarely fail because an assay produced poor data. They fail because the interpretation of that data did not translate to biology outside the assay system The Assay Window Problem Every functional assay operates within a measurement window , and interpreting

Imagine running a calcium assay and discovering your compound shows only weak activity. Kenakin dives deep into a widely used, often misunderstood tool in early drug discovery: the calcium assay Revered for its convenience, the FLIPR assay provides rapid insights into receptor activity. with strategic clarity. 📍 Foundational Level | Calcium Assays 📚 Part of Terry Kenakin’s Pharmacology Unlock "Calcium Assays" now

Enhance your GPCR research with deeper assay insights for more effective results. Terry's Corner – Assay Volume Control in GPCR Drug Discovery This week in Terry’s Corner, you’ll learn But behind every “new” assay is a decade of design, failure, and rethinking.

The strategic challenge is knowing which early assays are truly non-negotiable, which mechanisms demand In this session, you’ll gain: Clarity on high-impact early safety assays and their compelling rationale Kenakin highlights the definitive role of patch clamp assays and how high-throughput adaptations have Liver-centric assays identify primary and secondary toxic mechanisms Reactive metabolite detection is Kenakin demonstrates how mechanistic assays allow for early warning, ensuring that compounds prone to

But what if the assay system itself  could be leveraged as a powerful experimental variable? Assay volume control does just that. The real question: are you letting your assay system dictate the wrong story? Clarify whether observed effects reflect true pharmacology or assay artifacts . Unlock Assay Volume Control Only in Terry’s Corner 🎬 Watch Course Trailers Not sure yet?

Overcoming them requires careful assay design and strategic use of the right fluorescent probes. For GPCR assay developers, HCS supports:  Quantitative visualization of receptor internalization and trafficking  • Live-cell kinetic measurements  unavailable to endpoint assays  Multiplexed assessment Why Traditional Radioligand Methods Fall Short for Modern Screening Needs Radioligand binding assays the gold standard for image-based GPCR assays.

Not because the assay failed technically, but because of what steady-state measurement structurally cannot A scaffold carrying both agonist and antagonist activity presents a detection problem that standard assays At steady state, the assay captures the net effect of whatever the compound is doing at equilibrium. It is incomplete in a way the assay cannot disclose by design. When a scaffold carries both activities, kinetic assays produce complex time-dependent response curves

is to obtain a fluorescent ligand suitable for the Tag-lite® binding assays. (Ki) and saturation Tag-lite® binding assay (Kd).   1  Competition radioligand binding assay.  2  Saturation assay by Tag-lite® binding assay.  3  Displacement of specific [3H]-CP55940 binding in human HEK-CB1 assay and Kd= 42nM in Tag-lite®). Saturation assays using CELT-335.

Homogeneous Time-Resolved Fluorescence Assays: Overcoming Common Challenges Balancing sensitivity and This technology enhances sensitivity and assay specificity . Saturation assays using CELT-335. A Robust and Efficient FRET-Based Assay for Cannabinoid Receptor Ligands Discovery. A Robust and Efficient FRET-Based Assay for Cannabinoid Receptor Ligands Discovery.

Thus, developing assays for commercially available probes such as CELT-419 would facilitate research Fluorescence anisotropy (FA) assay has been used to study the ligand binding kinetics of many GPCRs.[ assays, the radioligand binding method was used.  The estimated Z’ of the assay is 0.71, which is sufficient for HTS standards. Figure 3.   provide more information and alternatives for binding assays.

August 2022 In vitro assays for the functional characterization of (psychedelic) substances at the serotonin More specifically, this review covers assays to monitor the canonical G protein signaling pathway (e.g measuring G protein recruitment/activation, inositol phosphate accumulation, or Ca2+ mobilization), assays recruitment or signaling, and assays to monitor receptor conformational changes. mechanism and linked to its specific execution, as these may heavily impact the assay outcome."

Eric Trinquet, a veteran innovator behind functional GPCR assays like HTRF and IP-One, believes rigid But those failures are where new paths emerge, often leading to transformative tools like the IP1 assay Eric Trinquet Built to Fail, Built to Win: Inside the IP1 Assay Origin Story The IP-One assay didn’t Instead, they focused on equilibrium-based assays and zeroed in on IP1 accumulation—pioneering a clean “We did a full dose-response and saw antagonism—all in one plate-based assay.

partnership with Eurofins DiscoverX , a global leader in GPCR product solutions including cell-based assay years of GPCR expertise, Eurofins DiscoverX delivers one of the industry’s most comprehensive GPCR assay portfolios, encompassing over 90% of the human GPCRome with assays for human receptors, species orthologs “They offer more than assays—they build true scientific partnerships that help teams get the most from About Eurofins DiscoverX Eurofins DiscoverX is a global leader in GPCR cell-based assay technologies

Figure 1: cAMP accumulation assay. Figure 2: β-arrestin recruitment assay. These assays are available from Eurofins DiscoverX, Dr. and detection reagents, with complementary GLP1R and GIPR assays for combination work. And getting there took solving a specific, stubborn assay problem first.

Every GPCR assay that makes it to market carries years of failures, late-night ideas, risky bets, and Functional assays for GPCRs—especially Gq-coupled receptors—were notoriously messy. Calcium flux? Trinquet’s team asked a bolder question: could they design equilibrium-based assays for pathways no one Built to Fail, Built to Win: The IP One Gamble After the success of their cAMP assay, Trinquet’s team Months were spent debating assay design. IP1 isn’t naturally abundant or easy to detect.

kinetics ✅ A framework to classify antagonists and rank compounds by offset rate, using rapid calcium assays The Hemi-Equilibrium Problem Calcium assays look simple. Flip it around, and you’ve got a shortcut: use depression of max in calcium assays to rapidly rank offset The reality is dynamic—ligands arrive, depart, and interact in ways that standard assays often miss. suggestions Practical insights  distilled from decades of pharmacology experience Whether you’re validating assays

Does Your Assay Agree With the Literature? Your experiment gives a pKB of 8.0. Is that consistent, or is your assay biased? to: Confirm whether your mean truly overlaps with accepted values Verify if binding and functional assays interchangeable with existing ones Instead of vague comparisons, you’ll have statistical clarity on whether your assay suggestions Practical insights  distilled from decades of pharmacology experience Whether you’re validating assays

In this session, you’ll gain: Why saturation and displacement assays fail when protein stoichiometry The midpoint and maximum—core parameters for downstream modeling—are only meaningful when the assay fully Displacement Curves and the Illusion of Potency Displacement assays measure affinity when no traceable Removing coupling partners (e.g., GTPγS) collapses the system to a single low-affinity curve. Equilibration time:  Many assays stop before the system reaches equilibrium, especially with slow competitors

developed and validated a label-free, liquid chromatography-mass spectrometry (LC-MS) based cell binding assay This assay was applied to various target classes, with particular emphasis on those for which protein-based binding assay can be difficult to achieve. In another example, this assay was applied to an ion channel target with its agonists, of which the determined binding affinity was consistent with functional assays.

A compound shows no response in one assay, and we call it “selective.” It should hold regardless of receptor density or assay format. If the assay threshold is too high, real pharmacology becomes invisible. Modern assays allow isolation of discrete signaling nodes. It prevents false negatives caused by insensitive assays.

The final step involves introducing fluorophores suitable for the desired assays. Neither fluorescent P1 nor P3 showed good activity in calcium functional assays. Further assays were conducted in a more extensive manner. compound CELT-68 (based on P3) , demonstrated activity in cAMP assays (Figure 4, Table 1). Both are orthosteric ligands with antagonistic activity in Calcium and cAMP assays (Table 1).

Too often, fundamentals are undervalued: in vitro assays are treated as routine checkboxes, and ADME Predictive in vitro assays have dramatically reduced this attrition—but with success comes complacency Kenakin highlights predictive in vitro permeation assays  that enable early iteration Absorption failures Predictive Assays: Assumptions and Opportunities High-throughput PK panels have transformed discovery vitro–in vivo correlation depends on scaling assumptions and controls CYP inhibition, transporter assays

Watch Episode 176 The first time Michelle ran a cyclic AMP assay, she did it with a single-channel pipette Assay samples were layered on trays of ice. These weren’t quaint inconveniences. We were doing assays on ice, pipetting one sample at a time. Those early cyclic AMP assays weren’t just cold and slow — they were part of a bigger puzzle. Mini Timeline: Manual assay years — technical rigor as foundation Technology boom — scaling curiosity

2026 GPCR Pharmacology AMA: Receptor Theory, Biased Signaling & Assay Interpretation The first GPCR Pharmacology Kenakin will address receptor theory, assay interpretation, biased signaling, and practical drug discovery coefficients (log(τ/KA) or log(max/EC50)) Systematic comparison of biased agonists using modern functional assays For scientists working in GPCR programs, this connects functional assay data directly to translational What seems definitive during early screening can shift as assay systems, receptor expression levels,

August 2022 Luciferase-based GloSensor™ cAMP assay: Temperature optimization and application to cell-based The GloSensor™ cAMP assay enables real-time monitoring of signaling downstream of many GPCRs. However, it is crucial to optimize assay conditions such as temperature. Here, we describe the temperature sensitivity and reversibility of the GloSensor™ cAMP assay, and which Nevertheless, the GloSensor™ cAMP assay can be applied to analyze signaling by a wide range of GPCRs

By walking through saturation curves, displacement assays, stoichiometry pitfalls, and kinetic traps, Academic innovation moves discovery forward only when assays are validated, distributed, and adopted Majellaro, Johannes Broichhagen, and David Hodson discuss GLP-1 receptor probes, fluorescence-based assays