Orphan G-protein coupled receptor. Constitutively activates the G(q/11)/inositol phosphate and the G(s)-alpha/cAMP signaling pathways . Has spontaneous activity for beta-arrestin recruitment . Shows a reciprocal modulation of signaling functions with the melatonin receptor MTNR1B most likely through receptor heteromerization .
Subcellular locations: Cell membrane, Endosome membrane
Colocalizes with ARRB2 in the endosome .
Expressed in brain; detected in the basal forebrain, frontal cortex, caudate, putamen, thalamus and hippocampus.