title: Regulation of P2Y1 receptor traffic by sorting Nexin 1 is retromer independent.
abstract: The activity and traffic of G-protein coupled receptors (GPCRs) is tightly controlled. Recent work from our laboratory has shown that P2Y(1) and P2Y(12) responsiveness is rapidly and reversibly modulated in human platelets and that the underlying mechanism requires receptor trafficking as an essential part of this process. However, little is known about the molecular mechanisms underlying P2Y receptor traffic. Sorting nexin 1 (SNX1) has been shown to regulate the endosomal sorting of cell surface receptors either to lysosomes where they are downregulated or back to the cell surface. These functions may in part be due to interactions of SNX1 with the mammalian retromer complex. In this study, we investigated the role of SNX1 in P2Y receptor trafficking. We show that P2Y(1) receptors recycle via a slow recycling pathway that is regulated by SNX1, whereas P2Y(12) receptors return to the cell surface via a rapid route that is SNX1 independent. SNX1 inhibition caused a dramatic increase in the rate of P2Y(1) receptor recycling, whereas inhibition of Vps26 and Vps35 known to be present in retromer had no effect, indicating that SNX1 regulation of P2Y(1) receptor recycling is retromer independent. In addition, inhibition of SNX4, 6 and 17 proteins did not affect P2Y(1) receptor recycling. SNX1 has also been implicated in GPCR degradation; however, we provide evidence that P2Y receptor degradation is SNX1 independent. These data describe a novel function of SNX1 in the regulation of P2Y(1) receptor recycling and suggest that SNX1 plays multiple roles in endocytic trafficking of GPCRs.
authors.affiliation: Department of Physiology and Pharmacology, School of Medical Sciences, University Walk, University of Bristol, Bristol BS8 1TD, UK.
authors.forename: Shaista
authors.initials: S
authors.lastname: Nisar
authors.forename: Eamonn
authors.initials: E
authors.lastname: Kelly
authors.forename: Pete J
authors.initials: PJ
authors.lastname: Cullen
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Mundell
mesh_terms: D001792:Blood Platelets / Q000502:physiology; D006801:Humans; D021381:Protein Transport; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D058472:Receptors, Purinergic P2Y1; D058925:Receptors, Purinergic P2Y12; D058305:Sorting Nexins; D014407:Tumor Cells, Cultured; D033921:Vesicular Transport Proteins / Q000378:metabolism*
chemical_list: C546382:P2RY1 protein, human; C548576:P2RY12 protein, human; D043562:Receptors, G-Protein-Coupled; D018048:Receptors, Purinergic P2; D058472:Receptors, Purinergic P2Y1; D058925:Receptors, Purinergic P2Y12; C513978:SNX1 protein, human; C487895:SNX17 protein, human; C513981:SNX4 protein, human; C431150:SNX6 protein, human; D058305:Sorting Nexins; C498296:VPS26A protein, human; C419573:VPS35 protein, human; D033921:Vesicular Transport Proteins