title: Distinct clathrin-coated pits sort different G protein-coupled receptor cargo.
abstract: Upon activation, many G protein-coupled receptors (GPCRs) internalize by clathrin-mediated endocytosis and are subsequently sorted to undergo recycling or lysosomal degradation. Here we observe that sorting can take place much earlier than previously thought, by entry of different GPCRs into distinct populations of clathrin-coated pit (CCP). These distinct populations were revealed by analysis of two purinergic GPCRs, P2Y(1) and P2Y(12), which enter two populations of CCPs in a mutually exclusive manner. The mechanisms underlying early GPCR sorting involve differential kinase-dependent processes because internalization of P2Y(12) is mediated by GPCR kinases (GRKs) and arrestin, whereas P2Y(1) internalization is GRK- and arrestin-independent but requires protein kinase C. Importantly, the beta(2) adrenoceptor which also internalizes in a GRK-dependent manner also traffics exclusively to P2Y(12)-containing CCPs. Our data therefore reveal distinct populations of CCPs that sort GPCR cargo at the plasma membrane using different kinase-dependent mechanisms.
authors.affiliation: Department of Pharmacology, School of Medical Sciences, University Walk, Bristol BS8 1TD, UK. s.j.mundell@bris.ac.uk
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Mundell
authors.forename: Jiansong
authors.initials: J
authors.lastname: Luo
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Benovic
authors.forename: Pamela B
authors.initials: PB
authors.lastname: Conley
authors.forename: Alastair W
authors.initials: AW
authors.lastname: Poole
mesh_terms: D000911:Antibodies, Monoclonal / Q000378:metabolism; D019393:Arrestin / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure; D002966:Clathrin / Q000378:metabolism*; D003034:Coated Pits, Cell-Membrane / Q000378:metabolism*; D004705:Endocytosis / Q000502:physiology*; D006801:Humans; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D018343:Receptors, Adrenergic, beta-2 / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000378:metabolism; D058472:Receptors, Purinergic P2Y1; D058925:Receptors, Purinergic P2Y12
chemical_list: D000911:Antibodies, Monoclonal; D019393:Arrestin; D002966:Clathrin; C546382:P2RY1 protein, human; C548576:P2RY12 protein, human; D034741:RNA, Small Interfering; D018343:Receptors, Adrenergic, beta-2; D043562:Receptors, G-Protein-Coupled; D018048:Receptors, Purinergic P2; D058472:Receptors, Purinergic P2Y1; D058925:Receptors, Purinergic P2Y12; D011494:Protein Kinases