1. Gαi2 signaling promotes skeletal muscle hypertrophy, myoblast differentiation, and muscle regeneration.
- Author
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Minetti GC, Feige JN, Rosenstiel A, Bombard F, Meier V, Werner A, Bassilana F, Sailer AW, Kahle P, Lambert C, Glass DJ, and Fornaro M
- Subjects
- Animals, Enzyme Activation genetics, GTP-Binding Protein alpha Subunits, G12-G13 genetics, HEK293 Cells, Humans, Hypertrophy enzymology, Hypertrophy genetics, Hypertrophy pathology, Mice, Mice, Transgenic, Muscle Proteins genetics, Muscle Proteins metabolism, Muscular Atrophy enzymology, Muscular Atrophy genetics, Muscular Atrophy pathology, Mutation, Myoblasts, Skeletal pathology, NFATC Transcription Factors genetics, NFATC Transcription Factors metabolism, Protein Kinase C genetics, Protein Kinase C metabolism, Tripartite Motif Proteins, Tumor Necrosis Factor-alpha genetics, Tumor Necrosis Factor-alpha metabolism, Ubiquitin-Protein Ligases genetics, Ubiquitin-Protein Ligases metabolism, Cell Differentiation, GTP-Binding Protein alpha Subunits, G12-G13 metabolism, Myoblasts, Skeletal enzymology, Regeneration, Signal Transduction
- Abstract
Skeletal muscle atrophy results in loss of strength and an increased risk of mortality. We found that lysophosphatidic acid, which activates a G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptor, stimulated skeletal muscle hypertrophy through activation of Gα(i2). Expression of a constitutively active mutant of Gα(i2) stimulated myotube growth and differentiation, effects that required the transcription factor NFAT (nuclear factor of activated T cells) and protein kinase C. In addition, expression of the constitutively active Gα(i2) mutant inhibited atrophy caused by the cachectic cytokine TNFα (tumor necrosis factor-α) by blocking an increase in the abundance of the mRNA encoding the E3 ubiquitin ligase MuRF1 (muscle ring finger 1). Gα(i2) activation also enhanced muscle regeneration and caused a switch to oxidative fibers. Our study thus identifies a pathway that promotes skeletal muscle hypertrophy and differentiation and demonstrates that Gα(i2)-induced signaling can act as a counterbalance to MuRF1-mediated atrophy, indicating that receptors that act through Gα(i2) might represent potential targets for preventing skeletal muscle wasting.
- Published
- 2011
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