First Drug-Like Molecules That Directly Target β-Arrestins Discovered, Opening New Path for GPCR-Targeted Therapies
核心洞察
Duke researchers identified three drug-like molecules that directly bind β-arrestins and block their interaction with GPCRs without affecting G protein signaling.
Cryo-EM revealed one compound, Cmpd-5 (搜索), binds a previously unknown allosteric pocket on β-arrestin (搜索), changing its shape globally to prevent GPCR engagement.
The inhibitors worked even when the GLP-1 receptor (搜索) was stimulated by weight-loss drugs Ozempic and Wegovy, prolonging G protein signaling.
In a breakthrough more than a decade in the making, researchers at Duke University School of Medicine have identified the first drug-like molecules capable of directly targeting β-arrestins—key signaling proteins that regulate roughly one-third of all FDA-approved drug targets. The findings, published June 24 in Nature, provide the first pharmacological tools to control these proteins with precision and open a new frontier for designing therapies with improved specificity and fewer side effects.
The study, led by senior author Robert J. Lefkowitz, MD, Duke Health Distinguished Professor of Medicine, identified three compounds that disrupt multiple aspects of β-arrestin (搜索) function—blocking their recruitment to G protein-coupled receptors (GPCRs), preventing receptor desensitization and internalization, and shutting down β-arrestin–specific signaling pathways—while leaving G protein signaling intact.
“Alem could have published a creditable paper about these molecules 10 years ago,” Lefkowitz said of co-first author Alem W. Kahsai, PhD, assistant professor of medicine. “But he’s a perfectionist. He wanted to figure out how they actually work.”
A Decade-Long Pursuit of Pharmacological Precision
The team began with a broad, unbiased screen of the National Cancer Institute’s vast compound library to identify molecules that might bind β-arrestins. They then narrowed the field using assays that demonstrated which compounds physically interacted with the protein and stabilized it. The most promising candidates were studied in engineered human cell systems where researchers could track real-time GPCR signaling, and later in physiologically relevant immune and heart muscle cells to determine whether their effects extended beyond simplified laboratory models.
“We tested these compounds from every angle we could think of before we were convinced they were bona fide β-arrestin (搜索) inhibitors,” Kahsai said.
Through this stepwise process, three compounds emerged that consistently disrupted β-arrestin (搜索) function across multiple GPCRs, including the GLP-1 receptor (搜索)—the target of the widely used weight-loss drugs Ozempic and Wegovy. Even when the receptor was being stimulated by these drugs, adding the new compounds inhibited β-arrestin control and allowed G protein signaling to continue longer than usual.
Structural Insights Reveal an Allosteric Mechanism
A pivotal moment came when co-first author Natalia Pakharukova, PhD, a postdoctoral researcher, used cryo-electron microscopy to visualize one of the compounds, called Cmpd-5 (搜索), binding to a previously unknown pocket on β-arrestin (搜索). The structural analysis showed that the inhibitor works allosterically: when it binds to this pocket, it changes the shape of β-arrestin globally and prevents it from fully engaging with GPCRs.
This visualization provided the mechanistic clarity that Kahsai had sought for years, explaining how the molecules achieve their selective effects without directly interfering with the receptors themselves.
Implications for Drug Development
GPCRs are targeted by approximately one-third of all FDA-approved drugs, yet current therapies modulate both G protein and β-arrestin (搜索) pathways indiscriminately. The ability to dial specific signaling pathways up or down—what researchers call biased signaling—promises to improve treatment precision while reducing unwanted side effects.
Because GPCRs and β-arrestins are involved in conditions ranging from metabolism and immune responses to cardiovascular function and brain signaling, the discovery suggests new strategies for designing more targeted therapies across multiple therapeutic areas.
The study also dovetails with related findings from the same institution. In separate work, Sudarshan Rajagopal, MD, PhD, associate professor of medicine at Duke, and colleagues showed that β-arrestin (搜索) proteins can assemble into liquid-like clusters known as condensates that act as hubs organizing signaling molecules in space and time. Disrupting these condensates altered GPCR signaling and receptor internalization, linking the structures directly to function.
“Our work shows that these receptors signal in a way we didn't fully appreciate before,” Rajagopal said. “That's important because it suggests new, potentially druggable ways to target GPCR signaling.”
Together, these discoveries provide the first chemical tools for studying β-arrestins and point toward a new generation of pharmacological agents that could achieve greater therapeutic precision by selectively modulating arrestin-dependent pathways.