Publication Date:
2010-12-15
Description:
Insulin-like growth factor 1 (IGF-1) induces skeletal muscle maturation and enlargement (hypertrophy). These responses require protein synthesis and myofibril formation (myofibrillogenesis). However, the signaling mechanisms of myofibrillogenesis remain obscure. We found that IGF-1-induced phosphatidylinositol 3-kinase-Akt signaling formed a complex of nebulin and N-WASP at the Z bands of myofibrils by interfering with glycogen synthase kinase-3beta in mice. Although N-WASP is known to be an activator of the Arp2/3 complex to form branched actin filaments, the nebulin-N-WASP complex caused actin nucleation for unbranched actin filament formation from the Z bands without the Arp2/3 complex. Furthermore, N-WASP was required for IGF-1-induced muscle hypertrophy. These findings present the mechanisms of IGF-1-induced actin filament formation in myofibrillogenesis required for muscle maturation and hypertrophy and a mechanism of actin nucleation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Takano, Kazunori -- Watanabe-Takano, Haruko -- Suetsugu, Shiro -- Kurita, Souichi -- Tsujita, Kazuya -- Kimura, Sumiko -- Karatsu, Takashi -- Takenawa, Tadaomi -- Endo, Takeshi -- New York, N.Y. -- Science. 2010 Dec 10;330(6010):1536-40. doi: 10.1126/science.1197767.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Graduate School of Science, Chiba University, 1-33 Yayoicho, Inageku, Chiba 263-8522, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21148390" target="_blank"〉PubMed〈/a〉
Keywords:
Actin Cytoskeleton/*metabolism
;
Actins/*metabolism
;
Animals
;
COS Cells
;
Cercopithecus aethiops
;
Hypertrophy
;
Insulin-Like Growth Factor I/*metabolism
;
Mice
;
Mice, Inbred ICR
;
*Muscle Development
;
Muscle Proteins/chemistry/*metabolism
;
Muscle, Skeletal/metabolism/pathology
;
Myofibrils/metabolism
;
Phosphatidylinositol 3-Kinase/metabolism
;
Protein Binding
;
Protein Interaction Domains and Motifs
;
Proto-Oncogene Proteins c-akt/metabolism
;
RNA Interference
;
Sarcomeres/*metabolism
;
Signal Transduction
;
Wiskott-Aldrich Syndrome Protein, Neuronal/chemistry/*metabolism
;
src Homology Domains
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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