Muscle RING-finger 2 and 3 maintain striated-muscle structure and function

Dörte Lodka, Aanchal Pahuja, Cornelia Geers-Knörr, Renate J. Scheibe, Marcel Nowak, Jida Hamati, Clemens Köhncke, Bettina Purfürst, Tamara Kanashova, Sibylle Schmidt, David J. Glass, Ingo Morano, Arnd Heuser, Theresia Kraft, Rhonda Bassel-Duby, Eric N. Olson, Gunnar Dittmar, Thomas Sommer, Jens Fielitz*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

39 Citations (Scopus)

Abstract

Background: The Muscle-specific RING-finger (MuRF) protein family of E3 ubiquitin ligases is important for maintenance of muscular structure and function. MuRF proteins mediate adaptation of striated muscles to stress. MuRF2 and MuRF3 bind to microtubules and are implicated in sarcomere formation with noticeable functional redundancy. However, if this redundancy is important for muscle function in vivo is unknown. Our objective was to investigate cooperative function of MuRF2 and MuRF3 in the skeletal muscle and the heart in vivo. Methods: MuRF2 and MuRF3 double knockout mice (DKO) were generated and phenotypically characterized. Skeletal muscle and the heart were investigated by morphological measurements, histological analyses, electron microscopy, immunoblotting, and real-time PCR. Isolated muscles were subjected to in vitro force measurements. Cardiac function was determined by echocardiography and working heart preparations. Function of cardiomyocytes was measured in vitro. Cell culture experiments and mass-spectrometry were used for mechanistic analyses. Results: DKO mice showed a protein aggregate myopathy in skeletal muscle. Maximal force development was reduced in DKO soleus and extensor digitorum longus. Additionally, a fibre type shift towards slow/type I fibres occurred in DKO soleus and extensor digitorum longus. MuRF2 and MuRF3-deficient hearts showed decreased systolic and diastolic function. Further analyses revealed an increased expression of the myosin heavy chain isoform beta/slow and disturbed calcium handling as potential causes for the phenotype in DKO hearts. Conclusions: The redundant function of MuRF2 and MuRF3 is important for maintenance of skeletal muscle and cardiac structure and function in vivo.

Original languageEnglish
Pages (from-to)165-180
Number of pages16
JournalJournal of Cachexia, Sarcopenia and Muscle
Volume7
Issue number2
DOIs
Publication statusPublished - 1 May 2016
Externally publishedYes

Keywords

  • Heart failure
  • MAPKAPK
  • MuRF2
  • MuRF3
  • Protein homeostasis
  • Protein surplus myopathy

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