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Published September 19, 2023 | Version Supplemental material
Journal Article Open

Nanoscale details of mitochondrial constriction revealed by cryoelectron tomography

Creators

  • 1. ROR icon California Institute of Technology
  • 2. ROR icon University of Pennsylvania
  • 3. ROR icon Scripps Research Institute
  • 4. ROR icon Carnegie Mellon University
  • 5. ROR icon Hampshire College
  • 6. ROR icon Institute of Biological Chemistry, Academia Sinica
  • 7. ROR icon Brigham Young University

Abstract

Mitochondria adapt to changing cellular environments, stress stimuli, and metabolic demands through dramatic morphological remodeling of their shape, and thus function. Such mitochondrial dynamics is often dependent on cytoskeletal filament interactions. However, the precise organization of these filamentous assemblies remains speculative. Here, we apply cryogenic electron tomography to directly image the nanoscale architecture of the cytoskeletal-membrane interactions involved in mitochondrial dynamics in response to damage. We induced mitochondrial damage via membrane depolarization, a cellular stress associated with mitochondrial fragmentation and mitophagy. We find that, in response to acute membrane depolarization, mammalian mitochondria predominantly organize into tubular morphology that abundantly displays constrictions. We observe long bundles of both unbranched actin and septin filaments enriched at these constrictions. We also observed septin-microtubule interactions at these sites and elsewhere, suggesting that these two filaments guide each other in the cytosolic space. Together, our results provide empirical parameters for the architecture of mitochondrial constriction factors to validate/refine existing models and inform the development of new ones.

Copyright and License

© 2023 Biophysical Society.

Acknowledgement

We thank S. Chen and A. Malyutin at the California Institute of Technology cryo-EM facility and Bill Anderson at The Scripps Research Institute electron microscopy facility for microscope support, and Jean-Christophe Ducom at The Scripps Research Institute for computational support. We thank A. Collazo and S. Wilbert for technical assistance with confocal microscopy. We thank Catherine Oikonomou for her critical input on the manuscript. The confocal imaging was performed at the Biological Imaging Facility at Caltech, and the cryo-EM imaging was performed at the Beckman Institute Resource Center for Transmission Electron Microscopy at Caltech and the Scripps Research Institute Hazen Cryo-EM Microscopy Suite. this work was supported by NIH grant P50-AI150464 (to G.J.J.), the Nadia’s Gift Foundation Innovator Award from the Damon Runyon Cancer Foundation (DRR-65-21 to D.A.G.), NIH grant R01GM134020 and NSF grants DBI-1949629 and NSF IIS-2007595 (to M.X.), a David and Lucile Packard Fellowship for Science and Engineering (2019-69645) and NIH grants RM1GM136511 and R01GM134020 (to Y.-W.C.), and a Philadelphia Center off-campus study program award to M.H.H.

Contributions

Conceptualization, S.K.M., D.A.G., W.Y.Y., and G.J.J.; methodology, S.K.M. and D.A.G., sample preparation, S.K.M., D.A.G., M.M., and W.Y.Y.; data collection, S.K.M., D.A.G., M.M., and W.Y.Y.; segmentation, S.K.M., D.A.G., and M.J.D.; data analysis, S.K.M., D.A.G., X.Z., B.A.B., M.M., and M.H.H.; software/code development, S.K.M., X.Z., and B.A.B.; figure generation, S.K.M., D.A.G., X.Z., and B.A.B.; writing, S.K.M., D.A.G., X.Z., and M.H.H.; editing. S.K.M., D.A.G., X.Z., B.A.B., Y.-W.C., X.M., W.Y.Y., and G.J.J.; supervision, D.A.G., Y.-W.C., M.X., and G.J.J.

Supplemental Material

Supplemental material:

Figures S1-S6 (PDF)

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Additional details

Additional titles

Alternative title
Nanoscale details of mitochondrial fission revealed by cryo-electron tomography

Identifiers

PMCID
PMC10541493

Related works

Has version
Journal Article: PMC10541493 (PMCID)
Is supplemented by
Supplemental Material: https://ars.els-cdn.com/content/image/1-s2.0-S0006349523004812-mmc1.pdf (URL)

Funding

National Institutes of Health
P50-AI150464
Damon Runyon Cancer Research Foundation
DRR-65-21
National Institutes of Health
R01GM134020
National Science Foundation
DBI-1949629
National Science Foundation
IIS-2007595
David and Lucile Packard Foundation
2019-69645
National Institutes of Health
RM1GM136511
National Institutes of Health
R01GM134020
University of Pennsylvania

Dates

Accepted
2023-07-31
Accepted
Available
2023-08-01
Available online
Available
2023-09-19
Version of record

Caltech Custom Metadata

Caltech groups
Division of Biology and Biological Engineering (BBE)
Publication Status
Published