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Glycosylation can influence topogenesis of membrane proteins and reveals dynamic reorientation of nascent polypeptides within the translocon

Goder, V. and Bieri, C. and Spiess, M.. (1999) Glycosylation can influence topogenesis of membrane proteins and reveals dynamic reorientation of nascent polypeptides within the translocon. The Journal of cell biology, Vol. 147, H. 2. pp. 257-266.

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Official URL: http://edoc.unibas.ch/dok/A5258062

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Abstract

The topology of multispanning membrane proteins in the mammalian endoplasmic reticulum is thought to be dictated primarily by the first hydrophobic sequence. We analyzed the in vivo insertion of a series of chimeric model proteins containing two conflicting signal sequences, i.e., an NH(2)-terminal and an internal signal, each of which normally directs translocation of its COOH-terminal end. When the signals were separated by more than 60 residues, linear insertion with the second signal acting as a stop-transfer sequence was observed. With shorter spacers, an increasing fraction of proteins inserted with a translocated COOH terminus as dictated by the second signal. Whether this resulted from membrane targeting via the second signal was tested by measuring the targeting efficiency of NH(2)-terminal signals followed by polypeptides of different lengths. The results show that targeting is mediated predominantly by the first signal in a protein. Most importantly, we discovered that glycosylation within the spacer sequence affects protein orientation. This indicates that the nascent polypeptide can reorient within the translocation machinery, a process that is blocked by glycosylation. Thus, topogenesis of membrane proteins is a dynamic process in which topogenic information of closely spaced signal and transmembrane sequences is integrated.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Growth & Development > Biochemistry (Spiess)
UniBasel Contributors:Spiess, Martin
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
Publisher:Rockefeller University Press
ISSN:0021-9525
Note:Publication type according to Uni Basel Research Database: Journal article
Language:English
Identification Number:
Last Modified:31 Dec 2015 10:42
Deposited On:22 Mar 2012 13:19

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