søndag den 25. august 2019

Does OXA1L, MRM2 and MRRF protein activity compensate for complex V inefficiency in ME patient cells?

ATP synthesis by Complex V is less efficient in ME/CFS cells. The other mitochondrial complexes work harder to compensate (1).

Is this problem reflected in previous ME research?


Oxidase (cytochrome c) assembly 1-like (OXA1L) is a mitochondrial inner membrane protein. It is required for the insertion of integral membrane proteins into the mitochondrial inner membrane. Essential for the activity and assembly of cytochrome oxidase. Required for the correct biogenesis of complex V and complex I in mitochondria (2).

Knockdown of human Oxa1L impairs the biogenesis of complex V and NADH:ubiquinone oxidoreductase (3).

The C-terminal approximately 100-amino acid tail of Oxa1L (Oxa1L-CTT) binds to mitochondrial ribosomes and plays a role in the co-translational insertion of mitochondria-synthesized proteins into the inner membrane (4).

The gene OXA1L had changed DNA methylation profile and increased foldchange (2,01) in CD4+ T-cells from ME patients (5).


Mitochondrial rRNA methyltransferase 2 (also known as FTSJ2) is involved in mitoribosome assembly (6).

Defective MRM2 causes MELAS-like clinical syndrome (MELAS = mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (7).

The gene MRM2 had changed DNA methylation profile and increased foldchange (2,12) in CD4+ T cells from ME patients (5).

The gene MRM2 was hypomethylated (3'UTR) in peripheral mononuclear cells (PBMC) from ME patients (8).


Mitochondrial ribosome-recycling factor (MRRF) is responsible for the release of ribosomes from messenger RNA at the termination of protein biosynthesis. May increase the efficiency of translation by recycling ribosomes from one round of translation to another (2).

MRRF is essentiel for cell viability and depletion of MRRF leads to loss of mitochondrial complexes (9).

MRRF gene expresseion was increased in PBMC from ME patients (10, 11). 

Does OXA1L, MRM2 and MRRF protein activity compensate for complex V inefficiency in ME patient cells?


1) Missailidis, D.; Annesley, S.J.; Allan, C.Y.; Sanislav, O.; Lidbury, B.A.; Lewis, D.P.; Fisher, P.R. An isolated Complex V defect and dysregulated mitochondrial function in immortalized lymphocytes from ME/CFS patients. Submitted 2019.

Specific Mitochondrial Respiratory Defects & Compensatory Changes in ME/CFS Patient Cells

3) Stiburek et al. Knockdown of human Oxa1l impairs the biogenesis of F1Fo-ATP synthase and NADH:ubiquinone oxidoreductase. J Mol Biol. 2007 Nov 23;374(2):506-16. Epub 2007 Sep 20. https://www.ncbi.nlm.nih.gov/pubmed/17936786

4) Hauge et al: Properties of the C-terminal tail of human mitochondrial inner membrane protein Oxa1L and its interactions with mammalian mitochondrial ribosomes. J Biol Chem. 2010 Sep 3;285(36):28353-62. doi: 10.1074/jbc.M110.148262. Epub 2010 Jul 2. https://www.ncbi.nlm.nih.gov/pubmed/20601428

5) Brenu et al: Methylation profile of CD4+ T cells in CFS/ME. J. Clin Cell Immunol 5, 228https://www.omicsonline.org/open-access/methylation-profile-of-cd-t-cells-in-chronic-fatigue-syndromemyalgic-encephalomyelitis-2155-9899.1000228.php?aid=27598

6) Rorbach et al: MRM2 and MRM3 are involved in biogenesis of the large subunit of the mitochondrial ribosome. Mol Biol Cell, 2014, 25, 17.

7) Garone et al: Defective MRM2 causes MELAS-like clinical syndrome. Hum Mol Genet, 2017, 26, 21.

8) Trivedi et al: Identification of ME/CFS - associated DNA methylation patterns. Plos One 2018, 13, 7.

9) Rorbach et al: The human mitochondrial ribosome recycling factor is essential for cell viability. Nucleic Acids Research, 2008, 36, 18.

10) Kerr et al: Gene expression subtypes in patients with CFS/ME. JID, 2008, 197.

11) Frampton et al: Assessment of a 44 gene classifier for the evaluation of CFS from PBMC gene expression. Plos one, 2011, 6, 3.

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