Adenylyl cyclases combinatorially integrate opposing dopamine receptor signals
Dopamine receptors are divided into two families which exert opposing effects on the second messenger cyclic AMP (cAMP). While most neuronal cell types express a single receptor subtype, some neurons co-express opposing receptor subtypes. It remains unclear how these cells could resolve simultaneous stimulatory and inhibitory inputs. Here, we introduce a multiplexed assay that quantifies surface receptor abundance and dynamic cAMP output in single cells. Using this assay, together with mathematical modeling, we demonstrate that signals from opposing receptor subtypes are integrated flexibly by downstream adenylyl cyclases (ACs) rather than at the receptor level. Because AC isoforms exhibit unique biochemical properties, a cells AC expression profile determines whether conflicting inputs are cancelled, suppressed, or amplified. Brain transcriptome analysis indicates that co-expression of opposing dopamine receptors is associated with expression of specific AC isoforms predicted to sustain signaling during multi-receptor activation. Our results show that dopamine signal integration depends on the expression profiles of receptors and AC isoforms in a predictable way.