ER-associated protein biogenesis and degradation

All proteins of the secretory pathway are imported into the Endoplasmic Reticulum (ER). Fundamental processes located at the ER membrane are protein import and protein degradation. We aim to gain structural insights into these complexes by cryoelectron tomography and integrative modeling.

Structure of the native ER Translocon
Native ER Translocon
Structure of native ER translocon as determined Cryo-ET. Left: Magnified view of the Sec61 protein conducting channel, the core of the ER translocon. Right: Structure of ER translocon bound to the ribosome.

In eukaryotic cells, co-translational protein translocation across and insertion into the endoplasmic reticulum (ER) membrane requires an elaborate macromolecular machinery. While structural details of ribosomes bound to purified and solubilized constituents of the translocon have been elucidated in recent years, little structural knowledge of ribosomes, bound to the complete ER protein translocation machinery in a native membrane environment exists. We use cryoelectron tomography (Cryo-ET) to provide structural insights into the 80S ribosomes and its associated machinery. We study the translocation machinery in situ using rough ER-microsomes.

Further reading:

  1. Braunger K, Pfeffer S, Shrimal S, Gilmore R, Berninghausen O, Mandon EC, Becker T, Förster F, Beckmann R.
    Structural basis for coupling protein transport and N-glycosylation at the mammalian endoplasmic reticulum.
    Science (2018). PubMed, DOI:10.1126/science.aar7899.
  2. Pfeffer S, Dudek J, Schaffer M, Ng BG, Albert S, Plitzko JM, Baumeister W, Zimmermann R, Freeze HH, Engel BD, Förster F.
    Dissecting the molecular organization of the translocon-associated protein complex.
    Nat. Comm. 14516 (2017). DOI:10.1038/ncomms14516.
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  3. Pfeffer S, Dudek J, Zimmermann R, Förster F.
    Organization of the native ribosome-translocon complex at the mammalian endoplasmic reticulum membrane.
    Biochim. Biophys. Acta (2016). PubMed, DOI:10.1016/j.bbagen.2016.06.024.
  4. Mahamid J, Pfeffer S, Schaffer M, Villa E, Danev R, Kuhn Cuellar L, Förster F, Hyman AA, Plitzko JM, Baumeister W.
    Visualizing the molecular sociology at the HeLa cell nuclear periphery.
    Science 351:969-972 (2016). PubMed, DOI:10.1126/science.aad8857.
  5. Schuller JM, Beck F, Lossl P, Heck AJ, Förster F.
    Nucleotide-dependent conformational changes of the AAA+ ATPase p97 revisited.
    FEBS Lett. 590:595-604 (2016). PubMed, DOI:10.1002/1873-3468.12091.
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  6. Pfeffer P, Förster F.
    Sec61: a static framework for membrane-protein insertion.
    Channels 10:1-3 (2016). PubMed, DOI:10.1080/19336950.2015.1125737
  7. Pfeffer S, Burbaum L, Unverdorben P, Pech M, Chen Y, Zimmermann R, Beckmann R, Förster F.
    Structure of the native Sec61 protein-conducting channel.
    Nat. Comm. 6:8403 (2015). DOI:10.1038/ncomms9403 (open access).
  8. Pfeffer S, Förster F.
    Proteintranslation und Prozessierung in physiologischer Umgebung abgebildet.
    Biospektrum, 4:385-387 (2015). DOI:10.1007/s12268-015-0590-y, Biospektrum
  9. Pfeffer S*, Woellhaf MW*, Herrmann JM, Förster F.
    Organization of the mitochondrial translation machinery studied in situ by cryo-electron tomography.
    Nat. Commun. 6:6019 (2015). PubMed, DOI:10.1038/ncomms7019
    * equal contribution
    Laborjournal, VBio, Innovations-Report
  10. Förster F, Schuller JM, Unverdorben P, Aufderheide A.
    Emerging mechanistic insights into AAA complexes regulating proteasomal degradation degradation.
    Biomolecules 4:774-794 (2014). PubMed, DOI:10.3390/biom4030774 (open access)
  11. Pfeffer S*, Dudek J*, Gogala M, Schorr S, Linxweiler J, Lang S, Becker T, Beckmann R, Zimmermann R, Förster F.
    Structure of the mammalian oligosaccharyl-transferase complex in the native ER protein translocon.
    Nat. Commun. 5:3072 (2014). PubMed, DOI: 10.1038/ncomms4072
    * equal contribution
  12. Pfeffer S, Brandt F, Hrabe T, Lang S, Eibauer M, Zimmermann R, Förster F.
    Structure and 3D arrangement of ER membrane associated ribosomes.
    Structure 20:1508-18 (2012). PubMed, DOI: 10.1016/j.str.2012.06.010 (open access)
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