1. A Key Role for the Ubiquitin Ligase UBR4 in Myofiber Hypertrophy in Drosophila and Mice.
- Author
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Hunt LC, Stover J, Haugen B, Shaw TI, Li Y, Pagala VR, Finkelstein D, Barton ER, Fan Y, Labelle M, Peng J, and Demontis F
- Subjects
- Animals, Calmodulin-Binding Proteins genetics, Drosophila Proteins genetics, Drosophila melanogaster, Hypertrophy, Mice, Muscle Proteins genetics, Ubiquitin-Protein Ligases genetics, Ubiquitination, Calmodulin-Binding Proteins metabolism, Drosophila Proteins metabolism, Muscle Proteins metabolism, Myofibrils enzymology, Ubiquitin-Protein Ligases metabolism
- Abstract
Skeletal muscle cell (myofiber) atrophy is a detrimental component of aging and cancer that primarily results from muscle protein degradation via the proteasome and ubiquitin ligases. Transcriptional upregulation of some ubiquitin ligases contributes to myofiber atrophy, but little is known about the role that most other ubiquitin ligases play in this process. To address this question, we have used RNAi screening in Drosophila to identify the function of > 320 evolutionarily conserved ubiquitin ligases in myofiber size regulation in vivo. We find that whereas RNAi for some ubiquitin ligases induces myofiber atrophy, loss of others (including the N-end rule ubiquitin ligase UBR4) promotes hypertrophy. In Drosophila and mouse myofibers, loss of UBR4 induces hypertrophy via decreased ubiquitination and degradation of a core set of target proteins, including the HAT1/RBBP4/RBBP7 histone-binding complex. Together, this study defines the repertoire of ubiquitin ligases that regulate myofiber size and the role of UBR4 in myofiber hypertrophy., (Copyright © 2019 The Author(s). Published by Elsevier Inc. All rights reserved.)
- Published
- 2019
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