The signal sequence influences post-translational ER translocation at distinct stages

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dc.contributor.authorJohnson, N.
dc.contributor.authorHassdenteufel, S.
dc.contributor.authorTheis, M.
dc.contributor.authorPaton, A.
dc.contributor.authorPaton, J.
dc.contributor.authorZimmermann, R.
dc.contributor.authorHigh, S.
dc.contributor.editorPalazzo, A.F.
dc.date.issued2013
dc.description.abstractThe metazoan Sec61 translocon transports polypeptides into and across the membrane of the endoplasmic reticulum via two major routes, a well-established co-translational pathway and a post-translational alternative. We have used two model substrates to explore the elements of a secretory protein precursor that preferentially direct it towards a co- or post-translational pathway for ER translocation. Having first determined the capacity of precursors to enter ER derived microsomes post-translationally, we then exploited semi-permeabilized mammalian cells specifically depleted of key membrane components using siRNA to address their contribution to the membrane translocation process. These studies suggest precursor chain length is a key factor in the post-translational translocation at the mammalian ER, and identify Sec62 and Sec63 as important components acting on this route. This role for Sec62 and Sec63 is independent of the signal sequence that delivers the precursor to the ER. However, the signal sequence can influence the subsequent membrane translocation process, conferring sensitivity to a small molecule inhibitor and dictating reliance on the molecular chaperone BiP. Our data support a model where secretory protein precursors that fail to engage the signal recognition particle, for example because they are short, are delivered to the ER membrane via a distinct route that is dependent upon both Sec62 and Sec63. Although this requirement for Sec62 and Sec63 is unaffected by the specific signal sequence that delivers a precursor to the ER, this region can influence subsequent events, including both Sec61 mediated transport and the importance of BiP for membrane translocation. Taken together, our data suggest that an ER signal sequence can regulate specific aspects of Sec61 mediated membrane translocation at a stage following Sec62/Sec63 dependent ER delivery.
dc.description.statementofresponsibilityNicholas Johnson, Sarah Haßdenteufel, Melanie Theis, Adrienne W. Paton, James C. Paton, Richard Zimmermann, Stephen High
dc.identifier.citationPLoS One, 2013; 8(10):e75394-1-e75394-11
dc.identifier.doi10.1371/journal.pone.0075394
dc.identifier.issn1932-6203
dc.identifier.issn1932-6203
dc.identifier.orcidPaton, J. [0000-0001-9807-5278]
dc.identifier.urihttp://hdl.handle.net/2440/85570
dc.language.isoen
dc.publisherPublic Library of Science
dc.rights© 2013 Johnson et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
dc.source.urihttps://doi.org/10.1371/journal.pone.0075394
dc.subjectIntracellular Membranes
dc.subjectEndoplasmic Reticulum
dc.subjectRNA, Small Interfering
dc.subjectProtein Processing, Post-Translational
dc.subjectProtein Transport
dc.titleThe signal sequence influences post-translational ER translocation at distinct stages
dc.typeJournal article
pubs.publication-statusPublished

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