title: Myostatin induces cyclin D1 degradation to cause cell cycle arrest through a phosphatidylinositol 3-kinase/AKT/GSK-3 beta pathway and is antagonized by insulin-like growth factor 1.
abstract: Myostatin is a transforming growth factor beta superfamily member and is known as an inhibitor of skeletal muscle cell proliferation and differentiation. Exposure to myostatin induces G1 phase cell cycle arrest. In this study, we demonstrated that myostatin down-regulates Cdk4 activity via promotion of cyclin D1 degradation. Overexpression of cyclin D1 significantly blocked myostatin-induced proliferation inhibition. We further showed that phosphorylation at threonine 286 by GSK-3beta was required for myostatin-stimulated cyclin D1 nuclear export and degradation. This process is dependent upon the activin receptor IIB and the phosphatidylinositol 3-kinase/Akt pathway but not Smad3. Insulin-like growth factor 1 (IGF-1) treatment or Akt activation attenuated the myostatin-stimulated cyclin D1 degradation as well as the associated cell proliferation repression. In contrast, attenuation of IGF-1 signaling caused C2C12 cells to undergo apoptosis in response to myostatin treatment. The observation that IGF-1 treatment increases myostatin expression through a phosphatidylinositol 3-kinase pathway suggests a possible feedback regulation between IGF-1 and myostatin. These findings uncover a novel role for myostatin in the regulation of cell growth and cell death in concert with IGF-1.
authors.affiliation: National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Li
authors.forename: Zhenguo
authors.initials: Z
authors.lastname: Wu
authors.forename: Dahai
authors.initials: D
authors.lastname: Zhu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002453:Cell Cycle / Q000502:physiology*; D002460:Cell Line; D002478:Cells, Cultured; D019938:Cyclin D1 / Q000378:metabolism*; D038362:Glycogen Synthase Kinase 3 / Q000502:physiology*; D000071679:Glycogen Synthase Kinase 3 beta; D007334:Insulin-Like Growth Factor I / Q000037:antagonists & inhibitors / Q000502:physiology*; D020935:MAP Kinase Signaling System / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D055435:Myostatin; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000502:physiology*
chemical_list: D019938:Cyclin D1; D038362:Glycogen Synthase Kinase 3; D000071679:Glycogen Synthase Kinase 3 beta; D007334:Insulin-Like Growth Factor I; D055435:Myostatin; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D016212:Transforming Growth Factor beta; C525912:Mstn protein, mouse; C000605507:Gsk3b protein, mouse