Visualization and ligand-induced modulation of dopamine receptor dimerization at the single molecule level.
G protein-coupled receptors (GPCRs), including dopamine receptors, represent a group of important pharmacological targets. An increased formation of dopamine receptor D2 homodimers has been suggested to be associated with the pathophysiology of schizophrenia. Selective labeling and ligand-induced modulation of dimerization may therefore allow the investigation of the pathophysiological role of these dimers. Using TIRF microscopy at the single molecule level, transient formation of homodimers of dopamine receptors in the membrane of stably transfected CHO cells has been observed. The equilibrium between dimers and monomers was modulated by the binding of ligands; whereas antagonists showed a ratio that was identical to that of unliganded receptors, agonist-bound D2 receptor-ligand complexes resulted in an increase in dimerization. Addition of bivalent D2 receptor ligands also resulted in a large increase in D2 receptor dimers. A physical interaction between the protomers was confirmed using high resolution cryogenic localization microscopy, with ca. 9 nm between the centers of mass.
Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander University, Schuhstraße 19, 91052 Erlangen, Germany.
Alina
A
Tabor
Max Planck Institute for the Science of Light and Department of Physics, Friedrich-Alexander University, Günther-Scharowsky-Straße 1/ Bldg. 24, 91058 Erlangen, Germany.
Siegfried
S
Weisenburger
Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander University, Schuhstraße 19, 91052 Erlangen, Germany.
Ashutosh
A
Banerjee
Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander University, Schuhstraße 19, 91052 Erlangen, Germany.
Nirupam
N
Purkayastha
Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander University, Schuhstraße 19, 91052 Erlangen, Germany.
Jonas M
JM
Kaindl
Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander University, Schuhstraße 19, 91052 Erlangen, Germany.
Harald
H
Hübner
Max Planck Institute for the Science of Light and Department of Physics, Friedrich-Alexander University, Günther-Scharowsky-Straße 1/ Bldg. 24, 91058 Erlangen, Germany.
Luxi
L
Wei
Department of Psychiatry and Psychotherapy, Friedrich-Alexander University, Schwabachanlage 6, 91054 Erlangen, Germany.
Teja W
TW
Grömer
Department of Psychiatry and Psychotherapy, Friedrich-Alexander University, Schwabachanlage 6, 91054 Erlangen, Germany.
Johannes
J
Kornhuber
Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander University, Schuhstraße 19, 91052 Erlangen, Germany.
Nuska
N
Tschammer
The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London NW7 1AA, UK.
Nigel J M
NJ
Birdsall
The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London NW7 1AA, UK.
Gregory I
GI
Mashanov
Max Planck Institute for the Science of Light and Department of Physics, Friedrich-Alexander University, Günther-Scharowsky-Straße 1/ Bldg. 24, 91058 Erlangen, Germany.
Vahid
V
Sandoghdar
Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander University, Schuhstraße 19, 91052 Erlangen, Germany.
Peter
P
Gmeiner
D000818:Animals; D016466:CHO Cells; D003412:Cricetulus; D018492:Dopamine Antagonists / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008024:Ligands; D008856:Microscopy, Fluorescence; D011485:Protein Binding; D055503:Protein Multimerization; D021381:Protein Transport; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D059010:Single-Cell Analysis; D013134:Spiperone / Q000378:metabolism*
D018492:Dopamine Antagonists; D008024:Ligands; D017448:Receptors, Dopamine D2; D013134:Spiperone