Single-molecule methods for characterizing receptor dimers reveal metastable opioid receptor homodimers that induce functional modulation

Opioid receptors (ORs) are critical for endogenous and synthetic analgesics. OR homodimerization is considered important for their pharmacological diversity, but whether they form homodimers remains controversial. Here, we establish that the three classical ORs, μ-, κ-, and δ-ORs (MOR, KOR, and DOR, respectively) undergo repeated transient (120-180 ms) homodimerizations every few seconds. This is achieved by using single-molecule imaging and developing theories for analyzing single-molecule colocalization data, which provide key parameters, such as homodimer-monomer dissociation equilibrium constants and rate constants. Their 9-26 amino-acid C-terminal cytoplasmic domains, without sequence similarities, are involved in specific homodimerization, whereas the transmembrane domains provide less specific affinities. Using the membrane-permeable peptides mimicking the C-terminal homodimerization sequences which block homodimerizations, functions of monomers and homodimers were dissected. KOR and DOR homodimers, but not MOR homodimers, activate downstream G-proteins differently from monomers upon agonist addition, without influencing OR internalization. These findings guide strategies to enhance OR-based analgesia.

Authors

Institutions

Publication Details

Journal
Nature Communications
Published
2025-11-07
DOI
https://doi.org/10.1038/s41467-025-64694-3
Citations
3
Primary Topic
Receptor Mechanisms and Signaling
Type
article
Field-Weighted Citation Impact
2.42

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

Single-molecule methods for characterizing receptor dimers reveal metastable opioid receptor homodimers that induce functional modulation

Takahiro Fujiwara, Tatsushi Yokoyama, Koichiro M. Hirosawa, Masayuki Sakamoto et al.
3 citations
Nature Communications
Receptor Mechanisms and Signaling
2.42
article

Single-molecule methods for characterizing receptor dimers reveal metastable opioid receptor homodimers that induce functional modulation

Takahiro Fujiwara, Tatsushi Yokoyama, Koichiro M. Hirosawa, Masayuki Sakamoto, Ryoji Kise, Simone Pigolotti, Rinshi S. Kasai, Asuka Inoue, Taka A. Tsunoyama, Masataka Yanagawa, Ziya Kalay, Peng Zhou, Akihiro Kusumi, Amine Aladag
article en
3 citations

Abstract

Opioid receptors (ORs) are critical for endogenous and synthetic analgesics. OR homodimerization is considered important for their pharmacological diversity, but whether they form homodimers remains controversial. Here, we establish that the three classical ORs, μ-, κ-, and δ-ORs (MOR, KOR, and DOR, respectively) undergo repeated transient (120-180 ms) homodimerizations every few seconds. This is achieved by using single-molecule imaging and developing theories for analyzing single-molecule colocalization data, which provide key parameters, such as homodimer-monomer dissociation equilibrium constants and rate constants. Their 9-26 amino-acid C-terminal cytoplasmic domains, without sequence similarities, are involved in specific homodimerization, whereas the transmembrane domains provide less specific affinities. Using the membrane-permeable peptides mimicking the C-terminal homodimerization sequences which block homodimerizations, functions of monomers and homodimers were dissected. KOR and DOR homodimers, but not MOR homodimers, activate downstream G-proteins differently from monomers upon agonist addition, without influencing OR internalization. These findings guide strategies to enhance OR-based analgesia.

Nature CommunicationsVol. 16(1)
Okinawa Institute of Science and Technology Graduate University (JP), Kyoto University (JP), Kyoto Pharmaceutical University (JP), Gifu University (JP), National Cancer Research Institute (GB)
Japan Agency for Medical Research and Development, Ministry of Education, Culture, Sports, Science and Technology, Okinawa Institute of Science and Technology Graduate University, University of California, San Diego, Japan Society for the Promotion of Science, ACT-X, Moonshot Research and Development Program
Openalex Percentile: Top 10%
Receptor Mechanisms and Signaling
2.42
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.