Functions and Mechanisms of the Human Ribosome-Translocon Complex

Sven Lang*, Duy Nguyen, Stefan Pfeffer, Friedrich Förster, Volkhard Helms, Richard Zimmermann

*Corresponding author for this work

    Research output: Chapter in Book/Report/Conference proceedingChapterAcademicpeer-review

    Abstract

    The membrane of the endoplasmic reticulum (ER) in human cells harbors the protein translocon, which facilitates membrane insertion and translocation of almost every newly synthesized polypeptide targeted to organelles of the secretory pathway. The translocon comprises the polypeptide-conducting Sec61 channel and several additional proteins, which are associated with the heterotrimeric Sec61 complex. This ensemble of proteins facilitates ER targeting of precursor polypeptides, Sec61 channel opening and closing, and modification of precursor polypeptides in transit through the Sec61 complex. Recently, cryoelectron tomography of translocons in native ER membranes has given unprecedented insights into the architecture and dynamics of the native, ribosome-associated translocon and the Sec61 channel. These structural data are discussed in light of different Sec61 channel activities including ribosome receptor function, membrane insertion or translocation of newly synthesized polypeptides as well as the possible roles of the Sec61 channel as a passive ER calcium leak channel and regulator of ATP/ADP exchange between cytosol and ER.

    Original languageEnglish
    Title of host publicationSubcellular Biochemistry
    Place of PublicationCham
    PublisherSpringer
    Chapter4
    Pages83-141
    Number of pages59
    ISBN (Electronic)978-3-030-28151-9
    ISBN (Print)978-3-030-28150-2
    DOIs
    Publication statusPublished - 1 Jan 2019

    Publication series

    NameSubcellular Biochemistry
    Volume93
    ISSN (Print)0306-0225

    Keywords

    • Endoplasmic reticulum
    • Membrane protein biogenesis
    • Protein secretion
    • Protein targeting
    • Protein translocation
    • Sec61 channel

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