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标题：G protein-coupled receptor 56 regulates mechanical overload-induced muscle hypertrophy
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作者：James P. White ; Christiane D. Wrann ; Rajesh R. Rao 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2014
卷号：111
期号：44
页码：15756-15761
DOI：10.1073/pnas.1417898111
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceThe work reported in this paper describes a previously unknown signaling pathway in skeletal muscle acting through G protein-coupled receptor 56-Galpha12/13. This discovery elucidates a previously unknown mechanism of muscle anabolism and gives another target of investigation for therapies against the loss of muscle mass seen with aging and various wasting diseases. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha 4 (PGC-14) is a protein isoform derived by alternative splicing of the PGC1 mRNA and has been shown to promote muscle hypertrophy. We show here that G protein-coupled receptor 56 (GPR56) is a transcriptional target of PGC-14 and is induced in humans by resistance exercise. Furthermore, the anabolic effects of PGC-14 in cultured murine muscle cells are dependent on GPR56 signaling, because knockdown of GPR56 attenuates PGC-14-induced muscle hypertrophy in vitro. Forced expression of GPR56 results in myotube hypertrophy through the expression of insulin-like growth factor 1, which is dependent on G12/13 signaling. A murine model of overload-induced muscle hypertrophy is associated with increased expression of both GPR56 and its ligand collagen type III, whereas genetic ablation of GPR56 expression attenuates overload-induced muscle hypertrophy and associated anabolic signaling. These data illustrate a signaling pathway through GPR56 which regulates muscle hypertrophy associated with resistance/loading-type exercise.
关键词：GPR56 ; mTOR ; Gα12/13 ; muscle hypertrophy ; overload