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Cell Death Differ. 2016 Mar;23(3):380-92. doi: 10.1038/cdd.2015.102. Epub 2015 Aug 7.

Mic60/Mitofilin determines MICOS assembly essential for mitochondrial dynamics and mtDNA nucleoid organization.

Author information

1
College of Life Sciences, Wuhan University, Room 4122, Wuhan 430072, PR China.
2
Scientific and Educational Department, Second Hospital of AnHui Medical University, 678 Furong Road, Hefei 230601, PR China.
3
State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, PR China.
4
School of Pharmaceutical Sciences, Wuhan University, Wuhan 430072, PR China.

Abstract

The MICOS complex (mitochondrial contact site and cristae organizing system) is essential for mitochondrial inner membrane organization and mitochondrial membrane contacts, however, the molecular regulation of MICOS assembly and the physiological functions of MICOS in mammals remain obscure. Here, we report that Mic60/Mitofilin has a critical role in the MICOS assembly, which determines the mitochondrial morphology and mitochondrial DNA (mtDNA) organization. The downregulation of Mic60/Mitofilin or Mic19/CHCHD3 results in instability of other MICOS components, disassembly of MICOS complex and disorganized mitochondrial cristae. We show that there exists direct interaction between Mic60/Mitofilin and Mic19/CHCHD3, which is crucial for their stabilization in mammals. Importantly, we identified that the mitochondrial i-AAA protease Yme1L regulates Mic60/Mitofilin homeostasis. Impaired MICOS assembly causes the formation of 'giant mitochondria' because of dysregulated mitochondrial fusion and fission. Also, mtDNA nucleoids are disorganized and clustered in these giant mitochondria in which mtDNA transcription is attenuated because of remarkable downregulation of some key mtDNA nucleoid-associated proteins. Together, these findings demonstrate that Mic60/Mitofilin homeostasis regulated by Yme1L is central to the MICOS assembly, which is required for maintenance of mitochondrial morphology and organization of mtDNA nucleoids.

PMID:
26250910
PMCID:
PMC5072434
[Available on 2017-03-01]
DOI:
10.1038/cdd.2015.102
[Indexed for MEDLINE]
Free PMC Article

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