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Cell Rep. 2017 Apr 18;19(3):487-496. doi: 10.1016/j.celrep.2017.03.063.

Power Grid Protection of the Muscle Mitochondrial Reticulum.

Author information

1
National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA. Electronic address: brian.glancy@nih.gov.
2
National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
3
National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.

Abstract

Mitochondrial network connectivity enables rapid communication and distribution of potential energy throughout the cell. However, this connectivity puts the energy conversion system at risk, because damaged elements could jeopardize the entire network. Here, we demonstrate the mechanisms for mitochondrial network protection in heart and skeletal muscle (SKM). We find that the cardiac mitochondrial reticulum is segmented into subnetworks comprising many mitochondria linked through abundant contact sites at highly specific intermitochondrial junctions (IMJs). In both cardiac and SKM subnetworks, a rapid electrical and physical separation of malfunctioning mitochondria occurs, consistent with detachment of IMJs and retraction of elongated mitochondria into condensed structures. Regional mitochondrial subnetworks limit the cellular impact of local dysfunction while the dynamic disconnection of damaged mitochondria allows the remaining mitochondria to resume normal function within seconds. Thus, mitochondrial network security is comprised of both proactive and reactive mechanisms in striated muscle cells.

KEYWORDS:

3D electron microscopy; energy distribution; mitochondrial dynamics; mitochondrial retraction; muscle energetics; oxidative phosphorylation

PMID:
28423313
PMCID:
PMC5490369
DOI:
10.1016/j.celrep.2017.03.063
[Indexed for MEDLINE]
Free PMC Article

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