Search Results

The drugs reshaping obesity and type 2 diabetes have made one principle clear: engaging a metabolic GPCR is not the same as engaging it well. The clinical success of GLP-1 and GIP receptor agonists has pushed the field toward additional pathways that might extend or deepen those benefits, and amylin signaling has become one of the most actively pursued. It is also one of the most structurally demanding targets a discovery team can take on, because the amylin receptor is not a single, fixed protein at all. Why there is no standalone amylin receptor Amylin, also known as islet amyloid polypeptide, is co-secreted with insulin from pancreatic beta cells. It slows gastric emptying, suppresses glucagon secretion, and promotes satiety, and through those actions it helps govern glucose homeostasis and energy balance. That physiology is what makes it such a compelling lever for metabolic disease. The pharmacology is unusual. No gene encodes a dedicated amylin receptor. The functional receptor assembles only when the calcitonin receptor (CALCR), a class B GPCR, associates with one of three receptor activity-modifying proteins, or RAMPs. CALCR partnered with RAMP1, RAMP2, or RAMP3 produces three distinct amylin receptors: AMY1, AMY2, and AMY3. One core receptor, three identities, each with distinct pharmacological properties that must be measured independently. Three subtypes, three pharmacologies This heteromeric architecture is the reason amylin-directed drug design is hard. The three subtypes do not behave interchangeably. A compound's activity at AMY1 does not reliably predict its activity at AMY2 or AMY3, and a molecule's selectivity across the set can shape both its therapeutic effect and its side-effect profile. Characterizing a candidate therefore means resolving its behavior at each subtype rather than treating the amylin receptor as one entity. For a discovery team, that turns subtype identity into a first-order design question. Which receptor is being engaged, how selectively, and what does engagement actually trigger downstream? Answering those questions cleanly, and early, is what separates a rationally designed amylin therapeutic from a promising binder. Biased signaling: reading cAMP against β-arrestin Potency is only part of the picture. Two compounds matched on potency can still differ in signaling bias, the degree to which each drives one downstream pathway relative to another. Figure 1: cAMP accumulation assay. Receptor activation drives adenylate cyclase and changes intracellular cAMP, detected through an enzyme fragment complementation readout that produces a luminescent signal proportional to cAMP. At AMY and CALCR complexes, the two readouts these assays capture are cAMP accumulation (Figure 1) and β-arrestin recruitment (Figure 2). Figure 2: β-arrestin recruitment assay. Agonist binding drives β-arrestin recruitment to the activated receptor, bringing two enzyme fragments together to produce a luminescent signal proportional to recruitment. A ligand that favors cAMP over β-arrestin, or the reverse, can produce a meaningfully different functional outcome even at matched receptor occupancy. For metabolic targets, where the line between efficacy and tolerability is narrow, those signaling fingerprints are increasingly where differentiated drugs are defined. Capturing these differences requires measuring both pathways in parallel, at each receptor subtype, with enough reproducibility to compare compounds against one another with confidence. The drug classes driving the questions The urgency behind all of this comes from the pipeline. Several next-generation strategies are competing in obesity and diabetes development at once: amylin agonists, dual amylin and calcitonin receptor agonists (DACRAs), and GLP-1/amylin co-agonists. Each makes different demands on the receptor, and each benefits from a clear picture of subtype selectivity and signaling bias. That picture also has to extend beyond amylin alone. Because so many programs now pursue combination, dual, and triple-agonist approaches, profiling amylin pharmacology alongside GLP1R and GIPR signaling lets teams understand how a co-agonist behaves across all of its intended targets rather than one at a time. What amylin receptor signaling looks like when you can measure it Resolving this used to mean assembling partial readouts from mismatched sources. A suite of pathway-reflective, cell-based assays now enables direct profiling of CALCR and amylin receptor subtypes (AMY1, AMY2, AMY3). These systems provide quantitative readouts of ligand activity across both cAMP signaling and β-arrestin recruitment, allowing researchers to compare signaling profiles, detect biased agonism, and resolve subtype-specific pharmacology with high reproducibility. Covering the full arc of discovery, from screening to mechanistic profiling, they enable confident rank-ordering of compounds across all relevant receptor configurations. These assays are available from Eurofins DiscoverX, Dr. GPCR's Strategic Partner, across cell line assays, ready-to-use eXpress kits, membrane preparations, and detection reagents, with complementary GLP1R and GIPR assays for combination work. The throughline The lesson running through this generation of metabolic medicines is that signaling quality and selectivity, alongside potency, are what separate a candidate from a therapy. For amylin, that means seeing clearly across three closely related receptors and two signaling pathways. And getting there took solving a specific, stubborn assay problem first. Prefer to hear it straight from the bench? Gaurav Agrawal of Eurofins DiscoverX walks through the problem one scientist to another. He studied how GPCRs activate during his PhD and uncovered a new intracellular trafficking pathway as a postdoc, and he now works alongside the scientists running amylin programs, which keeps him close to the assay problems they hit. He walks through why a standard cell line reports calcitonin instead of amylin, and how the team built a line that finally reads real amylin pharmacology. In this conversation ► 00:00 The amylin receptor challenge, and why it matters now ► 00:40 The Novo dual-agonist data that drew the field in ► 01:40 What an amylin receptor really is: calcitonin plus a RAMP ► 02:30 Three amylin receptors, and which drive weight loss ► 03:00 The stoichiometry problem behind the assay ► 04:00 Why a naive readout reports calcitonin, not amylin ► 06:00 The low-expression promoter approach ► 07:00 Reading the real MOAs: cyclic AMP and β-arrestin ► 07:40 Ortholog assays: mouse, rat, and bridging in vivo data ► 08:40 A characterized amylin portfolio, from profiling to potency Once an amylin receptor line reports real amylin pharmacology instead of calcitonin, the rest follows: clean cAMP and β-arrestin readouts, the subtypes that matter for weight loss, and ortholog assays that tie bench data back to in vivo work. ► Explore the AMY/CALCR portfolio

Introduction G protein-coupled receptors (GPCRs) don't simply switch on or off. Most are pleiotropically coupled to multiple intracellular pathways, and different ligands at the same receptor can produce fundamentally different cellular outcomes, a phenomenon known as GPCR signaling bias, or functional selectivity. Two molecules with identical binding affinity can diverge sharply in their downstream effects: one emphasizing G protein activation, another driving receptor internalization and β-arrestin recruitment, each producing a distinct pharmacological fingerprint. Measuring GPCR signaling bias in drug discovery is critical, as it forms a selection criterion for agonism. Measuring and quantifying signaling bias reveals which candidates emphasize therapeutically beneficial pathways, and which may be falsely characterized as equivalent by single-pathway assays. Drug discovery programs that do not consider investigating for signaling bias often fail to fully understand the distinction and risk candidate molecules from advancing along the pipeline. In this article, you'll learn: Four reasons why bias measurements improve candidate selection at every stage of the discovery pipeline How biased ligands can emphasize beneficial signaling pathways, and actively suppress harmful ones How bias can expand pursuit of targets previously considered too toxic or undruggable Why measuring signaling bias across multiple pathways gives a more accurate picture of true molecular selectivity Obtaining a GPCR Pathway Pharmacological Fingerprint To obtain a pharmacological fingerprint (or profile) for GPCR therapeutics, it is best to show how signaling bias and receptor selectivity can be quantified using cell-based assays. These assays offer a simple approach to the comparison of agonist profiles across different pathways and biased signaling. For example, Figure 1 shows cell-based assay results from the cAMP G protein activation pathway and the β-arrestin recruitment pathway for several incretins (metabolic hormones and therapeutics) acting on GLP-1 and GIP receptors. Both assays provide unique profiles and a preferred receptor signaling bias for the therapeutics tested. Figure 1. Dose-response curves for incretin agonists on GLP-1 and GIP receptors. Comparison of the curves reveals the relative selectivity of retratutide for GLP-1 receptor over GIP receptor compared to tirzepatide and yields sufficient data to calculate the signaling bias of the agonists for β-arrestin over cAMP responses. This data is calculated from the estimated max and EC50. How GPCR Signaling Bias Strengthens Drug Discovery Programs There are four distinct reasons why bias measurements improve drug discovery outcomes. Bias can make better drugs by emphasizing beneficial signaling pathways and de-emphasizing harmful ones. Opioid receptors offer clear illustration of this: G protein-biased agonists at the μ-opioid receptor have been explored as a strategy to preserve analgesia, while reducing β-arrestin-dependent adverse effects such as respiratory depression and constipation (Raehal et al., 2005; DeWire et al., 2013). Another example is at the angiotensin AT1 receptor, biased ligands like TRV120027 block deleterious vasoconstriction, while engaging β-arrestin signals that provide beneficial effects in heart failure (Violin et al., 2010). Bias measurements can identify structurally differentiated hits from high-throughput screens. Two hits from a primary screen may appear equivalent in a single-pathway assay but diverge significantly when tested in orthogonal functional assays. Counter-screening in biased assays distinguishes molecules that are genuinely different on a molecular level, and therefore more likely to produce distinct phenotypes in complex therapeutic models. Bias reduces complex efficacy profiles to measurable, optimizable scales for medicinal chemistry. Efficacy (comprising of both quality and quantity attributes for different agonists) reveals how an expected overall cellular response can be achieved from cellular signals. The quality attribute can be captured by bias measurements allowing for the reduction of complex phenotypes to graded activation of signaling pathways. Once a favorable efficacy fingerprint is identified in therapeutic cells (through cell-based assays), medicinal chemists can work backward to amplify or tune the relevant bias. Bias measurements are essential for accurate selectivity profiling. Quantifying bias offers a way to determine selectivity based on all known signaling for a given molecule. For instance, a compound that appears highly selective at a target receptor based on cAMP readouts alone may show far less selectivity when β-arrestin signaling is included. The β2-adrenoceptor bronchodilator clenbuterol, for example, exhibits 500-fold selectivity for β2 over β1 receptors in cyclic AMP assays, but exhibits a reduced selectivity (approximately 5.7-fold) when β-arrestin-mediated effects are measured (Casella et al., 2011). Without multi-pathway assays, selectivity assessments can be misleading. Emphasizing Beneficial and De-emphasizing Harmful Signaling Pathways One of the most powerful applications of GPCR biased signaling is the ability to separate therapeutic effects from adverse ones at the receptor level, not achieved with binary pharmacology. As different ligands stabilize different receptor conformations, it is possible to design molecules that selectively engage the beneficial pathways over harmful ones. The opioid system offers a highly studied example. Morphine provides effective analgesia but carries debilitating side effects including respiratory depression. Studies in β-arrestin knockout mice demonstrated that morphine produces significantly less respiratory depression in the absence of β-arrestin 2 signaling — pointing directly to a G protein-biased opioid agonist as a potentially superior analgesic, one that preserves pain relief while reducing a life-threatening adverse effect (Raehal et al., 2005; DeWire et al., 2013). The angiotensin system illustrates a more nuanced application: not just de-emphasizing a harmful pathway but blocking it while simultaneously preserving a beneficial one. In congestive heart failure, elevated angiotensin signaling raises arterial pressure resulting in the failure of the myocardium. Standard angiotensin receptor blockers like losartan address this, but at the cost of eliminating beneficial β-arrestin-mediated signals. Biased ligands such as TRV120027 block the deleterious G protein-driven effects, while retaining the beneficial β-arrestin signals offering a meaningfully improved therapeutic profile (Violin et al., 2010). Expanding the Druggable Target Space Through Bias Beyond refining the pharmacology of established targets, biased signaling can rehabilitate entire target classes previously considered too toxic to pursue. The κ-opioid receptor illustrates this directly. κ-Opioid agonists carry genuine therapeutic potential in mood, cognition, and addiction but also produce serious dysphoria, which has historically precluded clinical development. Biased κ-opioid agonists that reduce dysphoric signaling, while preserving beneficial effects, offer a route into a target class that unbiased pharmacology cannot safely access (White et al., 2014). Rather than abandoning a target because of a harmful pathway, bias offers a different answer: design around the liability. Conclusion Bias measurements reveal that efficacy has quality as well as quantity attributes, and that quality can be engineered. A biased ligand can be designed to favor pathways. For example, a pathway that build bones, relieve pain, or stabilize a failing heart, while avoiding pathways that cause respiratory depression, dysphoria, or dangerous arterial pressure. In the case of κ-opioid agonists, bias may be the only route by which an otherwise excluded target class becomes clinically viable at all. Bias quantification increases the value of known lead compounds, sharpens selectivity assessments, and provides medicinal chemists with graded, optimizable scales to work from. Programs that characterize signaling bias early — across G protein, β-arrestin, and second messenger pathways through cell-based assay assessments — carry forward candidates whose vivo behavior can be fully understood providing a meaningful selection criteria and competitive advantage at every stage of drug discovery. Eurofins DiscoverX provides the largest portfolio of GPCR assays and a unique service that utilizes state-of-the-art tools developed by Professor Terry Kenakin at the University of North Carolina School of Medicine for characterization of ligand bias. With the appropriate β-arrestin, internalization, and second messenger assays to quantify selective response and statistical tools to scale these effects, harnessing bias to produce selective ligands is now made simple. For further reading on GPCR biased signaling and assay methodologies, explore the ‘Insights into GPCR Drug Discovery and Development’ eBook and ‘GPCR Functional Cell-based Assays – Assessing Biased Signaling of Agonists’ White Paper by Kenakin, T. et al. (2025). Visit Eurofins DiscoverX GPCR Products and Solutions to explore the full portfolio of GPCR assays from Eurofins DiscoverX. References Raehal, K.M., Walker, J.K., & Bohn, L.M. (2005). Morphine side effects in beta-arrestin 2 knockout mice. Journal of Pharmacology and Experimental Therapeutics, 314(3), 1195–1201. https://doi.org/10.1124/jpet.105.087254 DeWire, S.M., Yamashita, D.S., Rominger, D.H., Liu, G., Cowan, C.L., Graczyk, T.M., … Violin, J.D. (2013). A G protein-biased ligand at the μ-opioid receptor is potently analgesic with reduced gastrointestinal and respiratory dysfunction compared with morphine. Journal of Pharmacology and Experimental Therapeutics, 344 (3), 708–717. https://doi.org/10.1124/jpet.112.201616 Violin, J.D., DeWire, S.M., Yamashita, D., Rominger, D.H., Nguyen, L., Schiller, K., … Lark, M.W. (2010). Selectively engaging β-arrestins at the angiotensin II type 1 receptor reduces blood pressure and increases cardiac performance. Journal of Pharmacology and Experimental Therapeutics, 335 (3), 572–579. https://doi.org/10.1124/jpet.110.173005 Casella, I., Ambrosio, C., Grò, M.C., Molinari, P., & Costa, T. (2011). Divergent agonist selectivity in activating β1- and β2-adrenoceptors for G protein and arrestin coupling. Biochemical Journal, 438 (1), 191–202. https://doi.org/10.1042/BJ20110374 Kenakin, T., Watson, C., Muniz-Medina, V., Christopoulos, A., & Novick, S. (2012). A simple method for quantifying functional selectivity and agonist bias. ACS Chemical Neuroscience, 3 (3), 193–203. https://doi.org/10.1021/cn200111m Kenakin, T. (2019). Biased receptor agonism. Annual Review of Pharmacology and Toxicology, 59, 245–267. https://doi.org/10.1146/annurev-pharmtox-010818-021139

A Result That Looks Clean but Isn't That interpretation may be wrong. Not because the assay failed technically, but because of what steady-state measurement structurally cannot reveal when two opposing activities are present in the same scaffold. This is the kinetic detection problem in multi-target GPCR activity, and it has consequences for how scaffolds are interpreted at early stages of discovery. What This Article Does Not Cover From This Week's Lesson The kinetic detection argument is one piece of the lesson. The lesson also works through: Why certain disease architectures require multi-target engagement in the first place, and the therapeutic contexts where single-receptor pharmacology is a precision mismatch Hybrid ligand design: how two pharmacophores are encoded into one scaffold, and why a uniform PK profile changes what co-administration cannot achieve How amino acid substitution within incretin peptide sequences shifts receptor selectivity across GLP-1, GIP, and glucagon receptor types The two-edged character of multi-target engagement: why therapeutic breadth and side effect liability advance together The detection problem examined in this article is the final piece. It is also the one most consequential for how multi-target compounds are evaluated once they exist. The Steady-State Cancellation Problem A scaffold carrying both agonist and antagonist activity presents a detection problem that standard assays are not designed to resolve. At steady state, the assay captures the net effect of whatever the compound is doing at equilibrium. If the agonist activity and the antagonist activity in the scaffold are roughly balanced, the net effect approaches zero. The readout is flat. The compound appears inert. Nothing in the steady-state result signals that two active processes are cancelling each other. The data is not incorrect. It is incomplete in a way the assay cannot disclose by design. Dynorphin A is a case that makes this concrete. The peptide sequence carries a region responsible for efficacy and a separate region that functions as a binding address. If a fragment loses the efficacy-bearing portion, what remains is an antagonist. In a preparation containing both the full agonist and the antagonist fragment, steady-state observation would reveal only a progressive reduction in response as the ratio of antagonist increases. The underlying dual activity remains invisible. What Kinetics Surfaces Agonist and antagonist activity do not proceed at the same rate. Onset kinetics differ. And those differences, invisible at equilibrium, become visible in real-time observation. When a scaffold carries both activities, kinetic assays produce complex time-dependent response curves. An initial agonist response emerges first. Then the antagonist effect, developing at a different rate, begins to modify it. The curve shape is not noise. It is a pharmacological signature of two processes with different temporal profiles. Dr. Kenakin describes this in the session: "You will see these complex curves. You see agonism, but then you'd start to see the other effect kick in. Kinetically, however, you might see it." Ambenonium demonstrates this with unusual clarity. The compound is simultaneously a muscarinic receptor inhibitor and a cholinesterase inhibitor, two activities that oppose each other functionally. At steady state, the effects cancel, and the compound appears to have no net action. In real-time observation, both activities emerge as distinct, time-separated signatures: one potentiating acetylcholine through cholinesterase inhibition, the other attenuating the response through receptor blockade. The compound is not inactive. It is pharmacologically complex in a way that steady-state measurement assigns no value to. What This Means for Multi-Target Programs The implication is practical. A scaffold that reads as inactive under standard screening conditions may carry multiple activities that are cancelling at equilibrium. Dismissing it on the basis of that result forecloses something that kinetic investigation might recover. The broader point is a methodological one. Steady-state assays answer the question they are designed to answer: what is the net effect at equilibrium? They are not designed to disaggregate that net effect into its components. When a multi-target scaffold is the subject of investigation, the question being asked and the information the assay returns may not match. Kinetic approaches reframe the question. Rather than asking what the compound's net effect is, they ask how the compound's effects develop over time. That reframing is what makes the underlying pharmacological complexity visible. Why Terry's Corner The kinetic detection argument is one piece of what the session covers. The lesson develops the surrounding framework: why certain disease architectures require multi-target engagement in the first place, the design strategies for building it into a single scaffold, and how peptide sequence modification shifts receptor selectivity in predictable directions. The detection problem examined here is the final piece, and the one most consequential for how multi-target compounds are evaluated once they exist. Terry's Corner is the room where pharmacologists work through frameworks like these alongside Dr. Terry Kenakin. Structured lessons are the foundation. Live AMAs and workshops are where the thinking comes alive, and where the question you've been sitting on finally has somewhere to go. 🟢 40 years of expertise at your fingertips: Explore the complete library ➤ ✳️ Want to know what's inside? Read the latest articles ➤ Stay sharp between lectures. Subscribe to The Kenakin Brief today ➤ Follow the thinking. Terry's Corner on LinkedIn ➤ Check out the YouTube Channel. Terry's Corner on YouTube ➤

Dr. GPCR Podcast - The Voice of the Community Whether you’re a scientist, student, or just curious, you’ll hear about discoveries, career stories, and the latest GPCR news. Jump in and get inspired! Strategic Partners Latest Podcast Episodes Select by Guest Name 2026-06-10 2026-04-29 2026-03-04 2025-12-17 2026-05-27 2026-04-01 2026-02-18 2025-12-03 2026-05-13 2026-03-18 2026-02-04 2025-11-19 1 2 3 4 5 1 ... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 ... 16 Enjoying the Dr. GPCR Podcast? Leave a Review. Leave a quick review to help more scientists find the show—and help us keep improving every episode. It takes <60 seconds and makes a big difference. ★ Review on Apple Podcasts ★ Rate on Spotify ✉️ Send feedback to the team Thanks for listening to this podcast episode Follow us on your favorite Podcast Player Listen and subscribe where you get your podcasts

Explore the world of GPCRs with Dr. GPCR Podcast! Join industry leaders as they share insights, stories, and groundbreaking discoveries, enriching our understanding of GPCRs. Delve into the science behind these vital components shaping our collective knowledge. Welcome to the Dr. GPCR Podcast - The Voice of the Community Conversations with the world’s leading GPCR scientists. Exploring discoveries, careers, and ideas shaping human health. In each episode, we sit down with leading experts to explore their career journeys, groundbreaking discoveries, and the impact of their research on our shared understanding of GPCR biology. Launched at the height of the pandemic, the Dr. GPCR Podcast was created with three goals: Share discoveries – Highlight the latest advances in the GPCR field. Amplify voices – Provide scientists a platform to showcase their work. Inspire the future – Motivate the next generation to pursue GPCR research. At its core, Dr. GPCR’s mission is simple yet ambitious: to bring the GPCR community together - across borders and disciplines - to connect, exchange, and collaborate in order to improve human health through a deeper understanding of GPCR biology. Latest Podcast Episodes More podcast episodes Dr. GPCR Podcast Audience Survey We are currently planning our next season and need your help. This short survey will help us understand your needs to bring you exciting and informative content. We also know that you are busy, which is why we designed this short survey that should take you 5 minutes. Fill out this form Be our Guest In each episode, we chat with an expert about their career trajectory, discoveries, and how their research contributed to the shared pool of knowledge about GPCR biology. We’d love to have you on our podcast. To be a guest, fill out the form below, and we’ll be in touch in 48 hours. Fill out this form What others are saying about this podcast "You made it a very comfortable and engaging experience, and it felt like we were chatting over coffee — Yamina thoughtfully guided our chat throughout." Anita Nivedha I think it's really well done. I'm genuinely interested to see how it evolves and grows over time, as I feel it has the potential to develop into something even more impactful. Anonymous This came at just the most perfect time. I hadn't heard a scientific talk outside my lab since February and was starved to hear someone else talk passionately about GPCRs. I've listened to the episodes multiple times and it's just like being at a conference getting new ideas. I just couldn't be happier y'all created this podcast. Anonymous Great initiative, thanks. Carrier paths, choosing research topics, switching fields, late start, failures and successes. Anonymous I enjoy the breadth of questioning that goes beyond just the science, and reveals a bit about the scientists as individuals/mentors/people. Anonymous Really enjoyable science podcast! Dr. Yamina Berchiche interviews leading GPCR scientists on this vibrant, entertaining podcast. I really appreciate the way the podcast educates and mentors, particularly towards junior scientists but also to the community as a wholen Yamina is a great interviewer, getting insight and personal history from her guests. Am very grateful for Dr GPCR livening up the week in these difficult times! Sam @Pharmamechanic Listen and subscribe where you get your podcasts

Learn about Celtarys Research through the Dr. GPCR Ecosystem. Explore their innovative GPCR projects, collaborations, and contributions to cutting-edge drug discovery. Partnership Dr. GPCR x Celtarys Reseach Empowering medicinal biochemists Celtarys empowers medicinal biochemists by providing innovative fluorescent probes that de-risk the pre-clinical drug discovery phase. Our proprietary conjugation technology and unparalleled scientific expertise ensure researchers can confidently advance their projects with greater precision and reliability. Visit Website About Celtarys Research Celtarys Research develops and commercializes new chemical tools to spread the use of fluorescence-based methods in the pre-clinical phase of drug discovery. Our proprietary chemical conjugation technology allows us to grow, in a competitive manner and in a short time (<3 months), customized fluorescent ligands with optimal pharmacological and photophysical properties for any druggable target. We have a catalogue of over 30 fluorescent ligands for different families of GPCRs, including adenosine, dopamine, serotonin, cannabinoid and muscarinic receptors. We also offer our expertise in the form of custom development services, where we tackle challenging targets and synthesize probes with the most suitable properties for your needs. Meet the Celtarys Team Wilson Gomes CEO Wilson Gomes holds a Mechanical Engineering degree, an MBA from the University of North Carolina, and completed the General Management Program at Harvard Business School. He has over 20 years of experience in the medtech and diagnostics industries, having held senior roles at Johnson & Johnson and Danaher across the EMEA region in sales, marketing, and general management. He joined Celtarys as CEO in 2024, where he is responsible for driving strategy and growth. His focus is on expanding commercial reach and accelerating the adoption of the company’s GPCR assay technologies. Maria Majellaro Co-Funder and CSO Dr. Maria Majellaro earned her degree in Pharmaceutical Chemistry and Technology from the University of Bari and completed her PhD in Biomolecular Sciences in Pharmacology and Medicine as “Doctor Europeus” in 2018. She then joined the University of Santiago de Compostela as a postdoctoral researcher in Prof. Eddy Sotelo’s group, contributing to the IGNICIA tech transfer project and the validation of Celtarys’ core technology. In 2021, she co-founded Celtarys and now leads the company’s scientific direction. Her work focuses on organic synthesis, medicinal chemistry, and the development of GPCR-targeted tools for pharma, biotech, and academic partners. Webinar Fluorescent Probes for GLP-1R and GIPR Imaging: From Cell Assays to In Vivo Systems Fluorescent tools for imaging endogenous incretin receptors across biological systems See Webinar Page Podcast Episodes See Podcast Page See Podcast Page See Podcast Page See Podcast Page Celtarys News & Updates A2A Fluorescent Competitive Binding: Advancing NanoBRET® Target Engagement for GPCR Drug Discovery The A₂A adenosine receptor NanoBRET® competitive binding assay enables real-time quantification of ligand–receptor interactions in living cells. By combining NanoLuc-tagged receptors with fluorescent tracers, this approach allows direct measurement of binding displacement, delivering robust pIC₅₀ and pKᵢ values that align with established pharmacology. In this article, we examine the assay principle, validation strategy, and performance across reference antagonists and agonis Lucía from Celtarys Research Mar 10 5 min read Illuminating C5aR Biology: The Role of Fluorescent Ligands in GPCR Research GPCRs are one of the most important families of therapeutic targets in the pharmaceutical industry. They are involved in several pathologies, ranging from neurological, oncological, degenerative, metabolic, immunological… around a third of the drugs in clinical use are GPCR ligands Lucía from Celtarys Research Feb 20 6 min read 1 2 3 4 5 Our Partnership Dr. GPCR and Celtarys Research Join Forces to Expand Access to Innovative GPCR Tools Boston, MA and Santiago de Compostela, Spain — June 3rd, 2025 — Dr. GPCR, the global knowledge hub for G protein-coupled receptor (GPCR) research and education, is proud to welcome Celtarys Research to its partner ecosystem. This collaboration aims to amplify the visibility and adoption of Celtarys’ cutting-edge fluorescent ligand technology and accelerate the development of GPCR-targeted therapeutics. Celtarys Research develops high-quality, fluorescently labeled ligands and innovative chemical biology tools to support real-time, non-radioactive GPCR assays. These tools enable high-resolution binding studies, kinetic analysis, and live-cell imaging, empowering both academic and industrial scientists to uncover GPCR biology with greater precision and speed. “We’re thrilled to partner with Celtarys and introduce their high-performance fluorescent ligands to our global GPCR community,” said Dr. Yamina Berchiche, Founder and CEO of Dr. GPCR. “These tools can dramatically improve how scientists measure ligand-receptor interactions, visualize binding in live cells, and design better experiments, core to advancing GPCR-targeted discovery.” “Dr. GPCR provides a unique platform to reach scientists at every stage of GPCR research,” said Wilson Gomes, CEO of Celtarys Research. “This partnership will help accelerate the adoption of our chemical tools and foster collaborations that turn receptor biology into therapeutic breakthroughs.” “We’re excited to support the GPCR community with tools that deliver clarity, sensitivity, and speed,” added Dr. Maria Majellaro, CSO of Celtarys. “Working with Dr. GPCR allows us to engage with researchers worldwide who are shaping the future of receptor-targeted therapies.” To explore Celtarys Research’s catalog and learn more about their GPCR tools, visit https://www.ecosystem.drgpcr.com/celtarys-research Services & Expertise NEW! High Content Screening Service Live‑cell HCS imaging in HEK‑293T–hCB2R with fluorescent ligand CELT-331; confocal capture on Operetta CLS. GPCR Expertise Specialized knowledge in adenosine, dopamine, serotonin, cannabinoid and muscarinic receptors for advanced research. Fluorescent Probes Innovative fluorescent probes that de-risk the pre-clinical drug discovery phase with optimal pharmacological properties. Custom Development Customized fluorescent ligands developed in less than 3 months with optimal properties for any druggable target. Product Catalog GPCR Ligands Our GPCR fluorescent ligands are the ideal solution for your High Throughput Screening (HTS) needs. GPCR Functional Assay Fluorescent GTPγS enables sensitive, non-radioactive GPCR activity assays for drug discovery. Custom Development Tailored fluorescent probes designed for unique research requirements. Contact Celtarys Research First name* Last name Email* Write a message Submit Get in Touch Address Avda. Mestre Mateo 2, Santiago de Compostela, 15706, Spain Email Website LinkedIn