RT Journal Article
SR Electronic
T1 Nanoscale details of mitochondrial fission revealed by cryo-electron tomography
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.12.13.472487
DO 10.1101/2021.12.13.472487
A1 Shrawan Kumar Mageswaran
A1 Danielle Ann Grotjahn
A1 Xiangrui Zeng
A1 Benjamin Asher Barad
A1 Michaela Medina
A1 My Hanh Hoang
A1 Megan J Dobro
A1 Yi-Wei Chang
A1 Min Xu
A1 Wei Yuan Yang
A1 Grant J. Jensen
YR 2021
UL http://biorxiv.org/content/early/2021/12/14/2021.12.13.472487.abstract
AB Mitochondrial fission is required for proper segregation during cell division, quality control, and cellular homeostasis (metabolism and energy production). Despite its importance, models of the process remain speculative. Here we apply cryogenic electron tomography to image the nanoscale architecture of mitochondrial fission in mammalian cells. We find that constriction of the inner and outer membranes is coordinated, suggesting that force on both membranes is applied externally. While we observe ER at constriction sites, it did not encircle constrictions. Instead, we find long bundles of both unbranched actin and septin filaments enriched at constrictions. Actin bundles align with the central region of division bridges and septin bundles with the necks on either side. Septin bundles appear to guide microtubules to constriction sites, suggesting, along with autolysosomes observed in the vicinity, a pathway for mitophagy. Together, our results rule out several existing models for mitochondrial fission and provide empirical parameters to inform the development of realistic coarse-grained models in the future.Competing Interest StatementThe authors have declared no competing interest.