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Structural Studies of Translocation Channels: The Nuclear Pore Complex and the Translocon

Published online by Cambridge University Press:  02 July 2020

Q. Yang ,
J-F. Ménétret ,
I.V. Akey ,
K. Plath ,
T. A. Rapoport  and
C. W. Akey
Q. Yang
Affiliation:
Department of Biophysics, Boston University School of Medicine715 Albany St., BostonMass02118-2526
J-F. Ménétret
Affiliation:
Department of Biophysics, Boston University School of Medicine715 Albany St., BostonMass02118-2526
I.V. Akey
Affiliation:
Department of Biophysics, Boston University School of Medicine715 Albany St., BostonMass02118-2526
K. Plath
Affiliation:
Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, BostonMass. 02115
T. A. Rapoport
Affiliation:
Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, BostonMass. 02115
C. W. Akey
Affiliation:
Department of Biophysics, Boston University School of Medicine715 Albany St., BostonMass02118-2526
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Extract

Protein translocation plays a critical role in the targeting of both soluble and membrane proteins to their correct intra- and inter-cellular compartments. We are studying the 3D architecture of two rather different translocation machines, the Nuclear Pore Complex (NPC) and the ribosome-Sec61p complex (translocon), with the aim of understanding their physical mechanisms of gating and transport. Towards this end, we are using single particle electron cryomicroscopy and 3D reconstruction of frozen hydrated specimens to obtain interpretable maps that are biologically relevant.

Previous work suggested that a central channel complex (termed the transporter) is present in vertebrate NPCs. Based on classification studies of the transporter and STEM images of Chironomus NPCs caught translocating large mRNPs, we have hypothesized that the transport mechanism utilizes a double iris-like gating mechanism, in which oppositely facing gates located at either end of the transporter open asynchronously. Recently, we have extended our studies to yeast NPCs and shown that this organelle is markedly smaller than its vertebrate cousin.

Type
Chambers and Channels: Functional Connections in Multiprotein Complexes Studied by Single Chambers and Channels
Information
Microscopy and Microanalysis , Volume 4 , Issue S2: Proceedings: Microscopy & Microanalysis '98, Microscopy Society of America 56th Annual Meeting, Microbeam Analysis Society 32nd Annual Meeting, Atlanta, Georgia July 12-16, 1998 , July 1998 , pp. 960 - 961
Copyright
Copyright © Microscopy Society of America

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References

References:

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6. This research was supported by NIH grants to CWA and TAR.Google Scholar