Skeletal Muscle-Specific Ablation of raptor, but Not of rictor, Causes Metabolic Changes and Results in Muscle Dystrophy

C. Florian Bentzinger, Klaas Romanino, Dimitri Cloëtta, Shuo Lin, Joseph B. Mascarenhas, Filippo Oliveri, Jinyu Xia, Emilio Casanova, Céline F. Costa, Marijke Brink, Francesco Zorzato, Michael N. Hall, Markus A. Rüegg

Research output: Contribution to journalArticlepeer-review

471 Scopus citations

Abstract

Mammalian target of rapamycin (mTOR) is a central controller of cell growth. mTOR assembles into two distinct multiprotein complexes called mTOR complex 1 (mTORC1) and mTORC2. Here we show that the mTORC1 component raptor is critical for muscle function and prolonged survival. In contrast, muscles lacking the mTORC2 component rictor are indistinguishable from wild-type controls. Raptor-deficient muscles become progressively dystrophic, are impaired in their oxidative capacity, and contain increased glycogen stores, but they express structural components indicative of oxidative muscle fibers. Biochemical analysis indicates that these changes are probably due to loss of activation of direct downstream targets of mTORC1, downregulation of genes involved in mitochondrial biogenesis, including PGC1α, and hyperactivation of PKB/Akt. Finally, we show that activation of PKB/Akt does not require mTORC2. Together, these results demonstrate that muscle mTORC1 has an unexpected role in the regulation of the metabolic properties and that its function is essential for life.

Original languageEnglish (US)
Pages (from-to)411-424
Number of pages14
JournalCell Metabolism
Volume8
Issue number5
DOIs
StatePublished - Nov 5 2008
Externally publishedYes

Keywords

  • HUMDISEASE

ASJC Scopus subject areas

  • Physiology
  • Molecular Biology
  • Cell Biology

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