Developing Photoaffinity Probes for Dopamine Receptor D2to Determine Targets of Parkinson's Disease Drugs

Spencer T. Kim, Emma J. Doukmak, Raymond G. Flax, Dylan J. Gray, Victoria N. Zirimu, Ebbing De Jong, Rachel C. Steinhardt

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Dopaminergic pathways control highly consequential aspects of physiology and behavior. One of the most therapeutically important and best-studied receptors in these pathways is dopamine receptor D2(DRD2). Unfortunately, DRD2 is challenging to study with traditional molecular biological techniques, and most drugs designed to target DRD2 are ligands for many other receptors. Here, we developed probes able to both covalently bind to DRD2 using photoaffinity labeling and provide a chemical handle for detection or affinity purification. These probes behaved like good DRD2 agonists in traditional biochemical assays and were able to perform in chemical-biological assays of cell and receptor labeling. Rat whole brain labeling and affinity enrichment using the probes permitted proteomic analysis of the probes' interacting proteins. Bioinformatic study of the hits revealed that the probes bound noncanonically targeted proteins in Parkinson's disease network as well as the retrograde endocannabinoid signaling, neuronal nitric oxide synthase, muscarinic acetylcholine receptor M1, GABA receptor, and dopamine receptor D1(DRD1) signaling networks. Follow-up analysis may yield insights into how this pathway relates specifically to Parkinson's disease symptoms or provide new targets for treatments. This work reinforces the notion that the combination of chemical biology and omics-based approaches provides a broad picture of a molecule's "interactome" and may also give insight into the pleiotropy of effects observed for a drug or perhaps indicate new applications.

Original languageEnglish (US)
Pages (from-to)3008-3022
Number of pages15
JournalACS Chemical Neuroscience
Issue number20
StatePublished - Oct 19 2022


  • DRD2
  • GABA receptor
  • bioinformatics
  • dopamine receptors
  • endocannabinoid pathway
  • muscarinic receptor M1
  • photo-cross-linking
  • photoaffinity labeling (PAL)
  • pramipexole
  • proteomics
  • ropinirole

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Cognitive Neuroscience
  • Cell Biology


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