title: Interactions between the Mas-related receptors MrgD and MrgE alter signalling and trafficking of MrgD.
abstract: When expressed via an inducible promoter in human embryonic kidney 293 cells, the rat Mas-related gene D (rMrgD) receptor responded to beta-alanine but not L-alanine by elevating intracellular [Ca(2+)], stimulating phosphorylation of the mitogenactivated protein kinases known as extracellular signal-regulated kinase (ERK) 1 and ERK2 and translocating from the plasma membrane to punctate intracellular vesicles. By contrast, the related rat Mas-related gene E (rMrgE) receptor did not respond to beta-alanine. Coexpression of rMrgD with rMrgE, which occurs in peripheral nociceptive neurons, allowed coimmunoprecipitation of the two receptors and resulted in the detection of cell surface rMrgD-rMrgE heterodimers via timeresolved fluorescence resonance energy transfer. These interactions increased the potency of beta-alanine to phosphorylate ERK1 and ERK2 as well as maintaining the capacity of beta-alanine to elevate intracellular [Ca(2+)], which was reduced in magnitude and slowed in response with increasing times of expression of rMrgD in isolation. Associated with these effects, the presence of rMrgE restricted beta-alanine-induced internalization of rMrgD. This is the first report of heterodimeric interactions between members of the Mas-related gene (Mrg) receptor family and indicates that interactions between rMrgD and rMrgE modulate the function of rMrgD. Because the Mrg receptors are potential therapeutic targets in pain, these results suggest that efforts to understand the function and regulation of individual Mrg family receptors may require coexpression of relevant pairs.
authors.affiliation: Molecular Pharmacology Group, Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, UK.
authors.forename: Sandra
authors.initials: S
authors.lastname: Milasta
authors.forename: John
authors.initials: J
authors.lastname: Pediani
authors.forename: Shirley
authors.initials: S
authors.lastname: Appelbe
authors.forename: Steven
authors.initials: S
authors.lastname: Trim
authors.forename: Michael
authors.initials: M
authors.lastname: Wyatt
authors.forename: Peter
authors.initials: P
authors.lastname: Cox
authors.forename: Mark
authors.initials: M
authors.lastname: Fidock
authors.forename: Graeme
authors.initials: G
authors.lastname: Milligan
mesh_terms: D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects; D002478:Cells, Cultured; D019281:Dimerization; D005727:Ganglia, Spinal / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D010766:Phosphorylation; D021381:Protein Transport; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D051381:Rats; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D015091:beta-Alanine / Q000494:pharmacology*
chemical_list: C508497:Mas-related receptor MrgD, rat; C508498:Mas-related receptor MrgE, rat; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D015091:beta-Alanine; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3