Lysergic acid diethylamide (LSD) acts through serotonin 5-HT2-family receptors, primarily 5-HT2A, but the closely related 5-HT2B receptor serves as a model due to its high expression. Cryo-electron microscopy structures of LSD-bound 5-HT2B in three states—transducer-free, coupled with Gq protein, and coupled with β-arrestin-1—reveal distinct signaling snapshots from a partially active to fully active states. These findings provide comprehensive molecular insights into LSD's signaling mechanisms and may accelerate the discovery of novel psychedelic drugs.
Treatments for pain or addiction targeting the κ-opioid receptor often cause hallucinogenic side effects. To understand this, cryo-electron microscopy mapped the receptor's structure with various G-proteins and compounds. These detailed maps uncovered molecular controls for G-protein binding and drug selectivity, showing distinct preferences. This clarifies opioid action, establishing a foundation for developing safer, pathway-selective therapies.
Classical psychedelics are being studied for treating depression, addiction, anxiety, and cluster headaches. Their therapeutic effects are thought to involve the 5-HT2A serotonin receptor. Seven cryo-EM structures were determined, covering major classes of psychedelic and non-psychedelic agonists, including a β-arrestin-biased compound. These structures reveal both common and distinct molecular interactions between different psychedelics and the receptor. The findings provide a mechanistic understanding of 5-HT2A activation that could aid development of new drugs with fewer side effects.