Correlated cryogenic fluorescence microscopy and electron cryo-tomography shows that exogenous TRIM5α can form hexagonal lattices or autophagy aggregates in vivo

Carter, S. D. , Mamede, J. I., Hope, T. J. and Jensen, G. J. (2020) Correlated cryogenic fluorescence microscopy and electron cryo-tomography shows that exogenous TRIM5α can form hexagonal lattices or autophagy aggregates in vivo. Proceedings of the National Academy of Sciences of the United States of America, 117(47), pp. 29702-29711. (doi: 10.1073/pnas.1920323117) (PMID:33154161) (PMCID:PMC7703684)

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Abstract

Members of the tripartite motif (TRIM) protein family have been shown to assemble into structures in both the nucleus and cytoplasm. One TRIM protein family member, TRIM5α, has been shown to form cytoplasmic bodies involved in restricting retroviruses such as HIV-1. Here we applied cryogenic correlated light and electron microscopy, combined with electron cryo-tomography, to intact mammalian cells expressing YFP-rhTRIM5α and found the presence of hexagonal nets whose arm lengths were similar to those of the hexagonal nets formed by purified TRIM5α in vitro. We also observed YFP-rhTRIM5α within a diversity of structures with characteristics expected for organelles involved in different stages of macroautophagy, including disorganized protein aggregations (sequestosomes), sequestosomes flanked by flat double-membraned vesicles (sequestosome:phagophore complexes), sequestosomes within double-membraned vesicles (autophagosomes), and sequestosomes within multivesicular autophagic vacuoles (amphisomes or autolysosomes). Vaults were also seen in these structures, consistent with their role in autophagy. Our data 1) support recent reports that TRIM5α can form both well-organized signaling complexes and nonsignaling aggregates, 2) offer images of the macroautophagy pathway in a near-native state, and 3) reveal that vaults arrive early in macroautophagy.

Item Type:Articles
Additional Information:This work was supported in part by NIH Grant AI150464 (to G.J.J. and T.J.H.).
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Carter, Dr Stephen
Authors: Carter, S. D., Mamede, J. I., Hope, T. J., and Jensen, G. J.
College/School:College of Medical Veterinary and Life Sciences > School of Infection & Immunity
College of Medical Veterinary and Life Sciences > School of Infection & Immunity > Centre for Virus Research
Journal Name:Proceedings of the National Academy of Sciences of the United States of America
Publisher:National Academy of Sciences
ISSN:0027-8424
ISSN (Online):1091-6490
Published Online:05 November 2020
Copyright Holders:Copyright © 2020 The Authors
First Published:First published in Proceedings of the National Academy of Sciences of the United States of America 117(47): 29702-29711
Publisher Policy:Reproduced under a Creative Commons License

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