Cited by 75Autophagy in Disease and TherapyMitochondrial Function and PathologyMuscle Physiology and Disorders

In mammalian skeletal muscle, phosphorylation of TOMM22 by protein kinase CSNK2/CK2 controls mitophagy

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Kravic, Bojana, Harbauer, Angelika B., Romanello, Vanina, Simeone, Luca, Vögtle, F.-Nora, Kaiser, Tobias, Straubinger, Marion, Huraskin, Danyil +17 more·2018·Autophagy

Abstract

In yeast, Tom22, the central component of the TOMM (translocase of outer mitochondrial membrane) receptor complex, is responsible for the recognition and translocation of synthesized mitochondrial precursor proteins, and its protein kinase CK2-dependent phosphorylation is mandatory for TOMM complex biogenesis and proper mitochondrial protein import. In mammals, the biological function of protein kinase CSNK2/CK2 remains vastly elusive and it is unknown whether CSNK2-dependent phosphorylation of TOMM protein subunits has a similar role as that in yeast. To address this issue, we used a skeletal muscle-specific Csnk2b/Ck2β-conditional knockout (cKO) mouse model. Phenotypically, these skeletal muscle Csnk2b cKO mice showed reduced muscle strength and abnormal metabolic activity of mainly oxidative muscle fibers, which point towards mitochondrial dysfunction. Enzymatically, active muscle lysates from skeletal muscle Csnk2b cKO mice phosphorylate murine TOMM22, the mammalian ortholog of yeast Tom22, to a lower extent than lysates prepared from controls. Mechanistically, CSNK2-mediated phosphorylation of TOMM22 changes its binding affinity for mitochondrial precursor proteins. However, in contrast to yeast, mitochondrial protein import seems not to be affected in vitro using mitochondria isolated from muscles of skeletal muscle Csnk2b cKO mice. PINK1, a mitochondrial health sensor that undergoes constitutive import under physiological conditions, accumulates within skeletal muscle Csnk2b cKO fibers and labels abnormal mitochondria for removal by mitophagy as demonstrated by the appearance of mitochondria-containing autophagosomes through electron microscopy. Mitophagy can be normalized by either introduction of a phosphomimetic TOMM22 mutant in cultured myotubes, or by in vivo electroporation of phosphomimetic Tomm22 into muscles of mice. Importantly, transfection of the phosphomimetic Tomm22 mutant in muscle cells with ablated Csnk2b restored their oxygen consumption rate comparable to wild-type levels. In sum, our data show that mammalian CSNK2-dependent phosphorylation of TOMM22 is a critical switch for mitophagy and reveal CSNK2-dependent physiological implications on metabolism, muscle integrity and behavior.

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Crossref · 10.1080/15548627.2017.1403716

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  • Absence of CK2 prevents import of PINK1 inside mitochondrial intermembrane space via TOM22 resulting in PINK1 accumulation, which triggers Parkin recruitment and mitophagy.

    “while the absence of casein kinase 2 (CK2) prevents the import of PINK1 inside the mitochondrial intermembrane space via TOM22 resulting in PINK1 accumulation, which triggers Parkin recruitment and mitophagy.”
  • Autophagy flux is impaired in CK2 knockout leading to formation of p62-positive protein aggregates and myopathy.

    “However, autophagy flux is impaired in CK2 knockout leading to the formation of p62-positive protein aggregates and myopathy83.”
  • Skeletal muscle-specific casein kinase 2 (CK2) deletion leads to a block of the autophagy and mitophagy flux that results in myopathy and muscle weakness.

    “Accordingly, skeletal muscle-specific casein kinase 2 (CK2) deletion leads to a block of the autophagy and mitophagy flux that results in myopathy and muscle weakness [229].”
  • There is an increase in autophagosome formation on mitochondria that cannot fuse with the lysosome, resulting in mitophagy impairment and mitochondrial dysfunction over time.

    “Consequently, there is an increase in autophagosome formation on mitochondria, that however, cannot fuse with the lysosome resulting in mitophagy impairment and mitochondrial dysfunction during the time [229].”
  • Reduced CK2-mediated TOMM22 phosphorylation weakens the binding between PINK1 and TOMM22, leading to decreased IMM PINK1 import and further OMM PINK1 accumulation.

    “The reduced CK2-mediated TOMM22 phosphorylation weakens the binding between PINK1 and TOMM22, leading to decreased IMM PINK1 import and further OMM PINK1 accumulation.”

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Authors
Kravic, B., Harbauer, A. B., Romanello, V., Simeone, L., Vögtle, F.-N., Kaiser, T., Straubinger, M., Huraskin, D., Böttcher, M., Cerqua, C., Martin, E. D., Poveda-Huertes, D., Buttgereit, A., Rabalski, A. J., Heuss, D., Rudolf, R., Friedrich, O., Litchfield, D., Marber, M., Salviati, L., Mougiakakos, D., Neuhuber, W., Sandri, M., Meisinger, C., & Hashemolhosseini, S.
Affiliations
  • Institute of Biochemistry, Medical Faculty, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen, Germany
  • University of Freiburg (DE)
  • University of Padua (IT)
  • Friedrich-Alexander-Universität Erlangen-Nürnberg (DE)
  • St Thomas' Hospital (GB)
  • Western University (CA)
  • Technische Hochschule Mannheim (DE)
Corresponding author
Hashemolhosseini, Said
Venue
Autophagy
Published
2018-02-01
Volume
14
Issue
2
Pages
311-335
ISSN
  • 1554-8627 (ISSN-L)
  • 1554-8635
OpenAlex
W2770295596
Cited by
75
References
82
Citations by year
2026: 6 · 2025: 3 · 2024: 13 · 2023: 10 · 2022: 14 · 2021: 10 · 2020: 12 · 2019: 5 · 2018: 2
FWCI
4.07
Type
journal article
Language
en
Open access
Locations
  • Autophagy (publishedVersion)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • Scholarship@Western (Western University) (submittedVersion)
  • Padua Research Archive (University of Padova) (submittedVersion)
Funders
  • European Union ERC (282310-MyoPHAGY)
  • AFM-Telethon (19524)
  • Foundation Leducq, AIRC (17388)
  • German Research Council DFG (HA 3309/1-3 & HA3309/3-1 to SH, Me1921/5-1 to CM)
  • Interdisciplinary Centre for Clinical Research at the University Hospital of the Friedrich-Alexander University of Erlangen-Nürnberg (E2 & E17)
Topics
  • Health Sciences › Medicine › Epidemiology › Autophagy in Disease and Therapy
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Mitochondrial Function and Pathology
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Muscle Physiology and Disorders
Keywords
mitophagy, protein phosphorylation, skeletal muscle, mitochondrial protein import, TOM complex, PINK1, mitochondrial dysfunction, oxidative muscle fibers, muscle strength, oxygen consumption, phosphomimetic mutant
MeSH terms
Mitochondrial Precursor Protein Import Complex Proteins, Animals, Autophagy, Humans, Mitochondria, Muscle, Phosphorylation, Signal Transduction, Mice, Knockout, Muscle, Skeletal, Protein Transport, Models, Animal, Mitochondrial Membrane Transport Proteins, Casein Kinase II, Mitochondrial Membranes, Mice, HEK293 Cells, Mitophagy

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