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Transmembrane domain–dependent partitioning of membrane proteins within the endoplasmic reticulum

The length and hydrophobicity of the transmembrane domain (TMD) play an important role in the sorting of membrane proteins within the secretory pathway; however, the relative contributions of protein–protein and protein–lipid interactions to this phenomenon are currently not understood. To investiga...

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Detalles Bibliográficos
Autores principales: Ronchi, Paolo, Colombo, Sara, Francolini, Maura, Borgese, Nica
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 2008
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2287291/
https://www.ncbi.nlm.nih.gov/pubmed/18391072
http://dx.doi.org/10.1083/jcb.200710093
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author Ronchi, Paolo
Colombo, Sara
Francolini, Maura
Borgese, Nica
author_facet Ronchi, Paolo
Colombo, Sara
Francolini, Maura
Borgese, Nica
author_sort Ronchi, Paolo
collection PubMed
description The length and hydrophobicity of the transmembrane domain (TMD) play an important role in the sorting of membrane proteins within the secretory pathway; however, the relative contributions of protein–protein and protein–lipid interactions to this phenomenon are currently not understood. To investigate the mechanism of TMD-dependent sorting, we used the following two C tail–anchored fluorescent proteins (FPs), which differ only in TMD length: FP-17, which is anchored to the endoplasmic reticulum (ER) membrane by 17 uncharged residues, and FP-22, which is driven to the plasma membrane by its 22-residue-long TMD. Before export of FP-22, the two constructs, although freely diffusible, were seen to distribute differently between ER tubules and sheets. Analyses in temperature-blocked cells revealed that FP-17 is excluded from ER exit sites, whereas FP-22 is recruited to them, although it remains freely exchangeable with the surrounding reticulum. Thus, physicochemical features of the TMD influence sorting of membrane proteins both within the ER and at the ER–Golgi boundary by simple receptor-independent mechanisms based on partitioning.
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spelling pubmed-22872912008-10-07 Transmembrane domain–dependent partitioning of membrane proteins within the endoplasmic reticulum Ronchi, Paolo Colombo, Sara Francolini, Maura Borgese, Nica J Cell Biol Research Articles The length and hydrophobicity of the transmembrane domain (TMD) play an important role in the sorting of membrane proteins within the secretory pathway; however, the relative contributions of protein–protein and protein–lipid interactions to this phenomenon are currently not understood. To investigate the mechanism of TMD-dependent sorting, we used the following two C tail–anchored fluorescent proteins (FPs), which differ only in TMD length: FP-17, which is anchored to the endoplasmic reticulum (ER) membrane by 17 uncharged residues, and FP-22, which is driven to the plasma membrane by its 22-residue-long TMD. Before export of FP-22, the two constructs, although freely diffusible, were seen to distribute differently between ER tubules and sheets. Analyses in temperature-blocked cells revealed that FP-17 is excluded from ER exit sites, whereas FP-22 is recruited to them, although it remains freely exchangeable with the surrounding reticulum. Thus, physicochemical features of the TMD influence sorting of membrane proteins both within the ER and at the ER–Golgi boundary by simple receptor-independent mechanisms based on partitioning. The Rockefeller University Press 2008-04-07 /pmc/articles/PMC2287291/ /pubmed/18391072 http://dx.doi.org/10.1083/jcb.200710093 Text en Copyright © 2008, The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Research Articles
Ronchi, Paolo
Colombo, Sara
Francolini, Maura
Borgese, Nica
Transmembrane domain–dependent partitioning of membrane proteins within the endoplasmic reticulum
title Transmembrane domain–dependent partitioning of membrane proteins within the endoplasmic reticulum
title_full Transmembrane domain–dependent partitioning of membrane proteins within the endoplasmic reticulum
title_fullStr Transmembrane domain–dependent partitioning of membrane proteins within the endoplasmic reticulum
title_full_unstemmed Transmembrane domain–dependent partitioning of membrane proteins within the endoplasmic reticulum
title_short Transmembrane domain–dependent partitioning of membrane proteins within the endoplasmic reticulum
title_sort transmembrane domain–dependent partitioning of membrane proteins within the endoplasmic reticulum
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2287291/
https://www.ncbi.nlm.nih.gov/pubmed/18391072
http://dx.doi.org/10.1083/jcb.200710093
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