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Biochem J. 2016 Oct 1;473(19):3341-54. doi: 10.1042/BCJ20160545. Epub 2016 Jul 19.

Membrane protein insertion and assembly by the bacterial holo-translocon SecYEG-SecDF-YajC-YidC.

Author information

1
School of Biochemistry, University of Bristol, Bristol BS8 1TD, U.K.
2
European Molecular Biology Laboratory, Grenoble Outstation, 6 rue Jules Horowitz, Grenoble 38042, France.
3
School of Biosciences, University of Birmingham, Birmingham B15 2TT, U.K.
4
Arbeitsgruppe Mikrobiologie, Fachbereich Biologie/Chemie, Universität Osnabrück, Osnabrück D-49069, Germany.
5
School of Biochemistry, University of Bristol, Bristol BS8 1TD, U.K. European Molecular Biology Laboratory, Grenoble Outstation, 6 rue Jules Horowitz, Grenoble 38042, France.

Abstract

Protein secretion and membrane insertion occur through the ubiquitous Sec machinery. In this system, insertion involves the targeting of translating ribosomes via the signal recognition particle and its cognate receptor to the SecY (bacteria and archaea)/Sec61 (eukaryotes) translocon. A common mechanism then guides nascent transmembrane helices (TMHs) through the Sec complex, mediated by associated membrane insertion factors. In bacteria, the membrane protein 'insertase' YidC ushers TMHs through a lateral gate of SecY to the bilayer. YidC is also thought to incorporate proteins into the membrane independently of SecYEG. Here, we show the bacterial holo-translocon (HTL) - a supercomplex of SecYEG-SecDF-YajC-YidC - is a bona fide resident of the Escherichia coli inner membrane. Moreover, when compared with SecYEG and YidC alone, the HTL is more effective at the insertion and assembly of a wide range of membrane protein substrates, including those hitherto thought to require only YidC.

KEYWORDS:

SecY; YidC; holo-translocon; insertion; membrane protein

PMID:
27435098
PMCID:
PMC5095914
DOI:
10.1042/BCJ20160545
[Indexed for MEDLINE]
Free PMC Article

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