Visualization of differential GPCR crosstalk in DRD1-DRD2 heterodimer upon different dopamine levels

• Published in: Progress in neurobiology Vol. 213; p. 102266
• Main Authors: Kim, Hyunbin, Nam, Min-Ho, Jeong, Sohyeon, Lee, Hyowon, Oh, Soo-Jin, Kim, Jeongjin, Choi, Nakwon, Seong, Jihye
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.06.2022
• Subjects: Brain - metabolism; cAMP; Dopamine; Dopamine receptor sensor; DRD1; DRD2; GPCR heterodimer; Humans; Receptors, Dopamine D1 - metabolism; Receptors, Dopamine D2 - metabolism; Signal Transduction; Tonic and phasic DA release; DRD1; Tonic and phasic DA release; DRD2; cAMP; GPCR heterodimer; Dopamine receptor sensor
• ISSN: 0301-0082; 1873-5118
• DOI: 10.1016/j.pneurobio.2022.102266

Dopaminergic signaling is regulated by transient micromolar (phasic) and background nanomolar (tonic) dopamine releases in the brain. These dopamine signals can be differentially translated by dopamine receptor type 1 and type 2, DRD1 and DRD2, which are G protein-coupled receptors (GPCRs). In response to dopamine, DRD1 and DRD2 are known to mediate opposite functions on cAMP production via Gs and Gi protein signaling. Interestingly, they can form a heterodimer. However, receptor crosstalk between DRD1-DRD2 heterodimers has not been directly measured, but it was only inferred from measuring downstream signaling pathways. Here we develop fluorescent protein-based multicolor biosensors which can monitor individual activation states of DRD1 and DRD2, and apply them to directly monitor the functional crosstalk between DRD1-DRD2 heterodimers in live cells. Utilizing these powerful tools, we surprisingly discover differential crosstalk in the DRD1-DRD2 heterodimers upon different dopamine (DA) levels: DRD1 activation is selectively inhibited at micromolar DA levels, while DRD2 is inhibited only by nanomolar DA concentration, implying a novel function of the DRD1-DRD2 heterodimer upon different DA levels. Our results imply differential receptor crosstalk and novel functions of the DRD1-DRD2 heterodimer in response to physiological dopamine levels from nanomolar to micromolar dopamine concentrations. [Display omitted] ●Development of new red fluorescent DRD1 sensor (R-DRD1) and green DRD2 sensor (G-DRD2).●Simultaneous monitoring of DRD1 and DRD2 activities by multicolor live-cell imaging.●Differential crosstalk in the DRD1-DRD2 heterodimer upon different dopamine levels.