Structure of a Hallucinogen-Activated Gq-Coupled 5-HT2A Serotonin Receptor

Cell. 2020 Sep 17;182(6):1574-1588.e19. doi: 10.1016/j.cell.2020.08.024.


Hallucinogens like lysergic acid diethylamide (LSD), psilocybin, and substituted N-benzyl phenylalkylamines are widely used recreationally with psilocybin being considered as a therapeutic for many neuropsychiatric disorders including depression, anxiety, and substance abuse. How psychedelics mediate their actions-both therapeutic and hallucinogenic-are not understood, although activation of the 5-HT2A serotonin receptor (HTR2A) is key. To gain molecular insights into psychedelic actions, we determined the active-state structure of HTR2A bound to 25-CN-NBOH-a prototypical hallucinogen-in complex with an engineered Gαq heterotrimer by cryoelectron microscopy (cryo-EM). We also obtained the X-ray crystal structures of HTR2A complexed with the arrestin-biased ligand LSD or the inverse agonist methiothepin. Comparisons of these structures reveal determinants responsible for HTR2A-Gαq protein interactions as well as the conformational rearrangements involved in active-state transitions. Given the potential therapeutic actions of hallucinogens, these findings could accelerate the discovery of more selective drugs for the treatment of a variety of neuropsychiatric disorders.

Keywords: GPCR; LSD; psychedelic; sertotonin receptor; signal transduction; structural biology.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Cryoelectron Microscopy
  • Crystallography, X-Ray
  • GTP-Binding Protein alpha Subunits, Gq-G11 / chemistry*
  • GTP-Binding Protein alpha Subunits, Gq-G11 / metabolism
  • Gene Expression
  • HEK293 Cells
  • Hallucinogens / chemistry*
  • Hallucinogens / pharmacology
  • Hallucinogens / therapeutic use
  • Humans
  • Ligands
  • Lysergic Acid Diethylamide / chemistry
  • Lysergic Acid Diethylamide / pharmacology
  • Methiothepin / chemistry
  • Methiothepin / metabolism
  • Models, Chemical
  • Mutation
  • Protein Conformation, alpha-Helical
  • Receptor, Serotonin, 5-HT2A / chemistry*
  • Receptor, Serotonin, 5-HT2A / genetics
  • Receptor, Serotonin, 5-HT2A / metabolism*
  • Recombinant Proteins
  • Serotonin / metabolism
  • Spodoptera


  • Hallucinogens
  • Ligands
  • Receptor, Serotonin, 5-HT2A
  • Recombinant Proteins
  • Serotonin
  • Methiothepin
  • Lysergic Acid Diethylamide
  • GTP-Binding Protein alpha Subunits, Gq-G11