Differences in the signaling pathways of α1A- and α1B-adrenoceptors are related to different endosomal targeting

Segura, V., Pérez-Aso, M., Montó, F., Carceller, E., Noguera, M.A., Pediani, J. , Milligan, G. , McGrath, I.C. and D’Ocon, P. (2013) Differences in the signaling pathways of α1A- and α1B-adrenoceptors are related to different endosomal targeting. PLoS ONE, 8(5), e64996. (doi:10.1371/journal.pone.0064996) (PMID:23717684) (PMCID:PMC3663791)

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Abstract

Aims: To compare the constitutive and agonist-dependent endosomal trafficking of α1A- and α1B-adrenoceptors (ARs) and to establish if the internalization pattern determines the signaling pathways of each subtype. Methods: Using CypHer5 technology and VSV-G epitope tagged α1A- and α1B-ARs stably and transiently expressed in HEK 293 cells, we analyzed by confocal microscopy the constitutive and agonist-induced internalization of each subtype, and the temporal relationship between agonist induced internalization and the increase in intracellular calcium (determined by FLUO-3 flouorescence), or the phosphorylation of ERK1/2 and p38 MAP kinases (determined by Western blot). Results and Conclusions: Constitutive as well as agonist-induced trafficking of α1A and α1B ARs maintain two different endosomal pools of receptors: one located close to the plasma membrane and the other deeper into the cytosol. Each subtype exhibited specific characteristics of internalization and distribution between these pools that determines their signaling pathways: α1A-ARs, when located in the plasma membrane, signal through calcium and ERK1/2 pathways but, when translocated to deeper endosomes, through a mechanism sensitive to β-arrestin and concanavalin A, continue signaling through ERK1/2 and also activate the p38 pathway. α1B-ARs signal through calcium and ERK1/2 only when located in the membrane and the signals disappear after endocytosis and by disruption of the membrane lipid rafts by methyl-β-cyclodextrin.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Milligan, Professor Graeme and Pediani, Dr John and McGrath, Professor Ian
Authors: Segura, V., Pérez-Aso, M., Montó, F., Carceller, E., Noguera, M.A., Pediani, J., Milligan, G., McGrath, I.C., and D’Ocon, P.
College/School:College of Medical Veterinary and Life Sciences
College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:PLoS ONE
Publisher:Public Library of Science
ISSN:1932-6203
Copyright Holders:Copyright © 2013 The Authors
First Published:First published in PLoS ONE 8(5):e64996
Publisher Policy:Reproduced under a Creative Commons License

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