Differential gene expression of muscle-specific ubiquitin ligase MAFbx/Atrogin-1 and MuRF1 in response to immobilization-induced atrophy of slow-twitch and fast-twitch muscles

Takeshi Okamoto, Suguru Torii, Shuichi Machida

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25 Citations (Scopus)


We examined muscle-specific ubiquitin ligases MAFbx/Atrogin-1 and MuRF1 gene expression resulting from immobilization-induced skeletal muscle atrophy of slow-twitch soleus and fast-twitch plantaris muscles. Male C57BL/6 mice were subjected to hindlimb immobilization, which induced similar percentage decreases in muscle mass in the soleus and plantaris muscles. Expression of MAFbx/Atrogin-1 and MuRF1 was significantly greater in the plantaris muscle than in the soleus muscle during the early stage of atrophy. After a 3-day period of atrophy, total FOXO3a protein level had increased in both muscles, while phosphorylated FOXO3a protein had decreased in the plantaris muscle, but not in the soleus muscle. PGC-1α protein expression did not change following immobilization in both muscles, but basal PGC-1α protein in the soleus was markedly higher than that in plantaris muscles. These data suggest that although soleus and plantaris muscles atrophied to a similar extent and that musclespecific ubiquitin protein ligases (E3) may contribute more to the atrophy of fast-twitch muscle than to that of slowtwitch muscle during immobilization.

Original languageEnglish
Pages (from-to)537-546
Number of pages10
JournalJournal of Physiological Sciences
Issue number6
Publication statusPublished - 2011 Nov



  • Fiber type
  • Immobilization
  • Muscle-specific ubiquitin ligase
  • Skeletal muscle atrophy

ASJC Scopus subject areas

  • Physiology

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