Torin1 restores proliferation rate in Charcot-Marie-Tooth disease type 2A cells harbouring MFN2 (mitofusin 2) mutation.

Abstract

Objective:

Mitofusin 2 (MFN2) is a mitochondrial outer membrane protein that serves primarily as a mitochondrial fusion protein but has additional functions including the tethering of mitochondrial-endoplasmic reticulum membranes, movement of mitochondria along axons, and control of the quality of mitochondria. Intriguingly, MFN2 has been referred to play a role in regulating cell proliferation in several cell types such that it acts as a tumour suppressor role in some forms of cancer. Previously, we found that fibroblasts derived from a Charcot-Marie-Tooth disease type 2A (CMT2A) patient with a mutation in the GTPase domain of MFN2 exhibit increased proliferation and decreased autophagy.

Methods:

Primary fibroblasts from a young patient affected by CMT2A harbouring c.650G > T/p.Cys217Phe mutation in the MFN2 gene were evaluated versus a healthy control to measure the proliferation rate by growth curves analysis and to assess the phosphorylation of protein kinase B (AKT) at Ser473 in response to different doses of torin1, a selective catalytic ATP-competitive mammalian target of rapamycin complex (mTOR) inhibitor, by immunoblot analysis.

Results:

Herein, we demonstrated that the mammalian target of rapamycin complex 2 (mTORC2) is highly activated in the CMT2AMFN2 fibroblasts to promote cell growth via the AKT(Ser473) phosphorylation-mediated signalling. We report that torin1 restores CMT2AMFN2 fibroblasts' growth rate in a dose-dependent manner by decreasing AKT(Ser473) phosphorylation.

Conclusions:

Overall, our study provides evidence for mTORC2, as a novel molecular target that lies upstream of AKT to restore the cell proliferation rate in CMT2A fibroblasts.

• Authors: Paola Zanfardino, Alessandro Amati, Easter Anna Petracca, Filippo M Santorelli, Vittoria Petruzzella
• Journal: Acta myologica : myopathies and cardiomyopathies : official journal of the Mediterranean Society of Myology (Acta Myol) Vol. 41 Issue 4 Pg. 201-206 ( 2022) ISSN: 2532-1900 [Electronic] Italy
• PMID: 36793649 (Publication Type: Journal Article)
• Copyright: ©2022 Gaetano Conte Academy - Mediterranean Society of Myology, Naples, Italy.

Chemical References

• Proto-Oncogene Proteins c-akt
• Mitochondrial Proteins
• Membrane Proteins
• TOR Serine-Threonine Kinases
• MFN2 protein, human
• GTP Phosphohydrolases

Topics

• Humans
• Charcot-Marie-Tooth Disease (genetics)
• Proto-Oncogene Proteins c-akt (genetics)
• Mutation
• Mitochondrial Proteins (genetics, metabolism)
• Membrane Proteins (genetics, metabolism)
• TOR Serine-Threonine Kinases (genetics)
• Cell Proliferation (genetics)
• GTP Phosphohydrolases (genetics)