Insights into the role and regulation of TCTP in skeletal muscle

The translationally controlled tumor protein (TCTP) is upregulated in a range of cancer cell types, in part, by the activation of the mechanistic target of rapamycin (mTOR). Recently, TCTP has also been proposed to act as an indirect activator of mTOR. While it is known that mTOR plays a major role...

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Bibliographic Details
Published in:Oncotarget 2017-03, Vol.8 (12), p.18754-18772
Main Authors: Goodman, Craig A, Coenen, Allison M, Frey, John W, You, Jae-Sung, Barker, Robert G, Frankish, Barnaby P, Murphy, Robyn M, Hornberger, Troy A
Format: Article
Language:English
Subjects:
Animals
Atrophy - metabolism
Atrophy - pathology
Biomarkers, Tumor - metabolism
Blotting, Western
Disease Models, Animal
Electroporation
Hypertrophy - metabolism
Hypertrophy - pathology
Immobilization
Immunohistochemistry
Mice
Mice, Inbred mdx
Muscle Denervation
Muscle, Skeletal - metabolism
Muscle, Skeletal - pathology
Research Paper
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Summary:The translationally controlled tumor protein (TCTP) is upregulated in a range of cancer cell types, in part, by the activation of the mechanistic target of rapamycin (mTOR). Recently, TCTP has also been proposed to act as an indirect activator of mTOR. While it is known that mTOR plays a major role in the regulation of skeletal muscle mass, very little is known about the role and regulation of TCTP in this post-mitotic tissue. This study shows that muscle TCTP and mTOR signaling are upregulated in a range of mouse models (mdx mouse, mechanical load-induced hypertrophy, and denervation- and immobilization-induced atrophy). Furthermore, the increase in TCTP observed in the hypertrophic and atrophic conditions occurred, in part, via a rapamycin-sensitive mTOR-dependent mechanism. However, the overexpression of TCTP was not sufficient to activate mTOR signaling (or increase protein synthesis) and is thus unlikely to take part in a recently proposed positive feedback loop with mTOR. Nonetheless, TCTP overexpression was sufficient to induce muscle fiber hypertrophy. Finally, TCTP overexpression inhibited the promoter activity of the muscle-specific ubiquitin proteasome E3-ligase, MuRF1, suggesting that TCTP may play a role in inhibiting protein degradation. These findings provide novel data on the role and regulation of TCTP in skeletal muscle in vivo.
ISSN:1949-2553
1949-2553
DOI:10.18632/oncotarget.13009