The E3 Ligase MuRF1 Degrades Myosin Heavy Chain Protein in Dexamethasone-Treated Skeletal Muscle

University of North Carolina at Chapel Hill, North Carolina, United States
Cell Metabolism (Impact Factor: 17.57). 12/2007; 6(5):376-85. DOI: 10.1016/j.cmet.2007.09.009
Source: PubMed


Skeletal muscle atrophy occurs as a side effect of treatment with synthetic glucocorticoids such as dexamethasone (DEX) and is a hallmark of cachectic syndromes associated with increased cortisol levels. The E3 ubiquitin ligase MuRF1 (muscle RING finger protein 1) is transcriptionally upregulated by DEX treatment. Differentiated myotubes treated with DEX undergo depletion of myosin heavy chain protein (MYH), which physically associates with MuRF1. This loss of MYH can be blocked by inhibition of MuRF1 expression. When wild-type and MuRF1(-/-) mice are treated with DEX, the MuRF1(-/-) animals exhibit a relative sparing of MYH. In vitro, MuRF1 is shown to function as an E3 ubiquitin ligase for MYH. These data identify the mechanism by which MYH is depleted under atrophy conditions and demonstrate that inhibition of a single E3 ligase, MuRF1, is sufficient to maintain this important sarcomeric protein.

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    • "Mice lacking atrogin-1 and MuRF1 are resistant to muscle atrophy in response to denervation and knockdown of atrogin-1 prevents muscle wasting induced by fasting (Bodine et al., 2001; Cong et al., 2011). It has been shown that MuRF1 interacts with and controls the half-life of several essential muscle structural proteins like troponin I (Kedar et al., 2004), MyHC (Clarke et al., 2007; Fielitz et al., 2007), and actin (Polge et al., 2011). So far only a few muscle proteins have been identified as substrates for atrogin-1. "
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