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Toc75‐V/OEP80 is processed during translocation into chloroplasts, and the membrane‐embedded form exposes its POTRA domain to the intermembrane space

Toc75‐V/OEP80 is processed during translocation into chloroplasts, and the membrane‐embedded form exposes its POTRA domain to the intermembrane space

Authors :
Lucia E. Gross
Nicole Spies
Stefan Simm
Enrico Schleiff
Source :
FEBS Open Bio, Vol 10, Iss 3, Pp 444-454 (2020)
Publication Year :
2020
Publisher :
Wiley, 2020.

Abstract

The insertion of membrane proteins requires proteinaceous complexes in the cytoplasm, the membrane, and the lumen of organelles. Most of the required complexes have been described, while the components for insertion of β‐barrel‐type proteins into the outer membrane of chloroplasts remain unknown. The same holds true for the signals required for the insertion of β‐barrel‐type proteins. At present, only the processing of Toc75‐III, the β‐barrel‐type protein of the central chloroplast translocon with an atypical signal, has been explored in detail. However, it has been debated whether Toc75‐V/ outer envelope protein 80 (OEP80), a second protein of the same family, contains a signal and undergoes processing. To substantiate the hypothesis that Toc75‐V/OEP80 is processed as well, we reinvestigated the processing in a protoplast‐based assay as well as in native membranes. Our results confirm the existence of a cleavable segment. By protease protection and pegylation, we observed intermembrane space localization of the soluble N‐terminal domain. Thus, Toc75‐V contains a cleavable N‐terminal signal and exposes its polypeptide transport‐associated domains to the intermembrane space of plastids, where it likely interacts with its substrates.

Details

Language :
English
ISSN :
22115463
Volume :
10
Issue :
3
Database :
Directory of Open Access Journals
Journal :
FEBS Open Bio
Publication Type :
Academic Journal
Accession number :
edsdoj.79d2f1056efb496eb33336572c84a42d
Document Type :
article
Full Text :
https://doi.org/10.1002/2211-5463.12791