title: UTP controls cell surface distribution and vasomotor activity of the human P2Y2 receptor through an epidermal growth factor receptor-transregulated mechanism.
abstract: Extracellular nucleotides transmit signals into the cells through the P2 family of cell surface receptors. These receptors are amply expressed in human blood vessels and participate in vascular tone control; however, their signaling mechanisms remain unknown. Here we show that in smooth muscle cells of isolated human chorionic arteries, the activation of the P2Y(2) receptor (P2Y(2)R) induces not only its partition into membrane rafts but also its rapid internalization. Cholesterol depletion with methyl-beta-cyclodextrin reduced the association of the agonist-activated receptor into membrane rafts but did not affect either the UTP-mediated vasoconstrictions or the vasomotor responses elicited by both serotonin and KCl. Ex vivo perfusion of human chorionic artery segments with 1-10 mum UTP, a selective P2Y(2)R agonist, displaced the P2Y(2)R localization into membrane rafts within 1 min, a process preceded by the activation of both RhoA and Rac1 GTPases. AG1478, a selective and potent inhibitor of the epidermal growth factor receptor tyrosine kinase activity, not only blocked the UTP-induced vasomotor activity but also abrogated both RhoA and Rac1 activation, the P2Y(2)R association with membrane rafts, and its internalization. Altogether, these results show for the first time that the plasma membrane distribution of the P2Y(2)R is transregulated by the epidermal growth factor receptor, revealing an unsuspected functional interplay that controls both the membrane distribution and the vasomotor activity of the P2Y(2)R in intact human blood vessels.
authors.affiliation: Departamento de Ciencias Fisiológicas, Facultad de Ciencias Biológicas, Centro de Regulación Celular y Patología JV Luco, Instituto Milenio de Biología Fundamental y Aplicada, Santiago, Chile. an2r@virginia.edu
authors.forename: Andrés
authors.initials: A
authors.lastname: Norambuena
authors.forename: Francisco
authors.initials: F
authors.lastname: Palma
authors.forename: M Inés
authors.initials: MI
authors.lastname: Poblete
authors.forename: M Verónica
authors.initials: MV
authors.lastname: Donoso
authors.forename: Evelyn
authors.initials: E
authors.lastname: Pardo
authors.forename: Alfonso
authors.initials: A
authors.lastname: González
authors.forename: J Pablo
authors.initials: JP
authors.lastname: Huidobro-Toro
mesh_terms: D000199:Actins / Q000737:chemistry; D001158:Arteries / Q000378:metabolism; D002823:Chorion / Q000098:blood supply*; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008024:Ligands; D021962:Membrane Microdomains / Q000378:metabolism; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D018048:Receptors, Purinergic P2 / Q000096:biosynthesis* / Q000737:chemistry; D058473:Receptors, Purinergic P2Y2; D015398:Signal Transduction; D014544:Uridine Triphosphate / Q000737:chemistry / Q000378:metabolism*; D014666:Vasomotor System / Q000502:physiology
chemical_list: D000199:Actins; D008024:Ligands; C546385:P2RY2 protein, human; D018048:Receptors, Purinergic P2; D058473:Receptors, Purinergic P2Y2; D066246:ErbB Receptors; D014544:Uridine Triphosphate