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The Cytoplasmic Tail of Rhodopsin Acts as a Novel Apical Sorting Signal in Polarized MDCK Cells

All basolateral sorting signals described to date reside in the cytoplasmic domain of proteins, whereas apical targeting motifs have been found to be lumenal. In this report, we demonstrate that wild-type rhodopsin is targeted to the apical plasma membrane via the TGN upon expression in polarized ep...

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Detalles Bibliográficos
Autores principales: Chuang, Jen-Zen, Sung, Ching-Hwa
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1998
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2149337/
https://www.ncbi.nlm.nih.gov/pubmed/9732285
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author Chuang, Jen-Zen
Sung, Ching-Hwa
author_facet Chuang, Jen-Zen
Sung, Ching-Hwa
author_sort Chuang, Jen-Zen
collection PubMed
description All basolateral sorting signals described to date reside in the cytoplasmic domain of proteins, whereas apical targeting motifs have been found to be lumenal. In this report, we demonstrate that wild-type rhodopsin is targeted to the apical plasma membrane via the TGN upon expression in polarized epithelial MDCK cells. Truncated rhodopsin with a deletion of 32 COOH-terminal residues shows a nonpolar steady-state distribution. Addition of the COOH-terminal 39 residues of rhodopsin redirects the basolateral membrane protein CD7 to the apical membrane. Fusion of rhodopsin's cytoplasmic tail to a cytosolic protein glutathione S-transferase (GST) also targets this fusion protein (GST–Rho39Tr) to the apical membrane. The targeting of GST–Rho39Tr requires both the terminal 39 amino acids and the palmitoylation membrane anchor signal provided by the rhodopsin sequence. The apical transport of GST–Rho39Tr can be reversibly blocked at the Golgi complex by low temperature and can be altered by brefeldin A treatment. This indicates that the membrane-associated GST–Rho39Tr protein may be sorted along a yet unidentified pathway that is similar to the secretory pathway in polarized MDCK cells. We conclude that the COOH-terminal tail of rhodopsin contains a novel cytoplasmic apical sorting determinant. This finding further indicates that cytoplasmic sorting machinery may exist in MDCK cells for some apically targeted proteins, analogous to that described for basolaterally targeted proteins.
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spelling pubmed-21493372008-05-01 The Cytoplasmic Tail of Rhodopsin Acts as a Novel Apical Sorting Signal in Polarized MDCK Cells Chuang, Jen-Zen Sung, Ching-Hwa J Cell Biol Articles All basolateral sorting signals described to date reside in the cytoplasmic domain of proteins, whereas apical targeting motifs have been found to be lumenal. In this report, we demonstrate that wild-type rhodopsin is targeted to the apical plasma membrane via the TGN upon expression in polarized epithelial MDCK cells. Truncated rhodopsin with a deletion of 32 COOH-terminal residues shows a nonpolar steady-state distribution. Addition of the COOH-terminal 39 residues of rhodopsin redirects the basolateral membrane protein CD7 to the apical membrane. Fusion of rhodopsin's cytoplasmic tail to a cytosolic protein glutathione S-transferase (GST) also targets this fusion protein (GST–Rho39Tr) to the apical membrane. The targeting of GST–Rho39Tr requires both the terminal 39 amino acids and the palmitoylation membrane anchor signal provided by the rhodopsin sequence. The apical transport of GST–Rho39Tr can be reversibly blocked at the Golgi complex by low temperature and can be altered by brefeldin A treatment. This indicates that the membrane-associated GST–Rho39Tr protein may be sorted along a yet unidentified pathway that is similar to the secretory pathway in polarized MDCK cells. We conclude that the COOH-terminal tail of rhodopsin contains a novel cytoplasmic apical sorting determinant. This finding further indicates that cytoplasmic sorting machinery may exist in MDCK cells for some apically targeted proteins, analogous to that described for basolaterally targeted proteins. The Rockefeller University Press 1998-09-07 /pmc/articles/PMC2149337/ /pubmed/9732285 Text en 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 Articles
Chuang, Jen-Zen
Sung, Ching-Hwa
The Cytoplasmic Tail of Rhodopsin Acts as a Novel Apical Sorting Signal in Polarized MDCK Cells
title The Cytoplasmic Tail of Rhodopsin Acts as a Novel Apical Sorting Signal in Polarized MDCK Cells
title_full The Cytoplasmic Tail of Rhodopsin Acts as a Novel Apical Sorting Signal in Polarized MDCK Cells
title_fullStr The Cytoplasmic Tail of Rhodopsin Acts as a Novel Apical Sorting Signal in Polarized MDCK Cells
title_full_unstemmed The Cytoplasmic Tail of Rhodopsin Acts as a Novel Apical Sorting Signal in Polarized MDCK Cells
title_short The Cytoplasmic Tail of Rhodopsin Acts as a Novel Apical Sorting Signal in Polarized MDCK Cells
title_sort cytoplasmic tail of rhodopsin acts as a novel apical sorting signal in polarized mdck cells
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2149337/
https://www.ncbi.nlm.nih.gov/pubmed/9732285
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