scholarly journals Insulin and Insulin-like Growth Factor I Receptors Utilize Different G Protein Signaling Components

2001 ◽  
Vol 276 (19) ◽  
pp. 15688-15695 ◽  
Author(s):  
Stephane Dalle ◽  
William Ricketts ◽  
Takeshi Imamura ◽  
Peter Vollenweider ◽  
Jerrold M. Olefsky
Keyword(s):  
Growth Factor ◽  
G Protein ◽  
G Protein Signaling ◽  
Insulin Like Growth Factor ◽  
Protein Signaling ◽  
Factor I ◽  
Growth Factor I ◽  
Signaling Components

Differential effect of sepsis on ability of leucine and IGF-I to stimulate muscle translation initiation

2004 ◽  
Vol 287 (4) ◽  
pp. E721-E730 ◽  
Author(s):  
Charles H. Lang ◽  
Robert A. Frost
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Growth Factor ◽  
Translation Initiation ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Growth Factor I ◽  
Signaling Components

Polymicrobial sepsis impairs skeletal muscle protein synthesis, which results from impairment in translation initiation under basal conditions. The purpose of the present study was to test the hypothesis that sepsis also impairs the anabolic response to amino acids, specifically leucine (Leu). Sepsis was induced by cecal ligation and puncture, and 24 h later, Leu or saline (Sal) was orally administered to septic and time-matched nonseptic rats. The gastrocnemius was removed 20 min later for assessment of protein synthesis and signaling components important in peptide-chain initiation. Oral Leu increased muscle protein synthesis in nonseptic rats. Leu was unable to increase protein synthesis in muscle from septic rats, and synthetic rates remained below those observed in nonseptic + Sal rats. In nonseptic + Leu rats, phosphorylation of eukaryotic initiation factor (eIF)4E-binding protein 1 (4E-BP1) in muscle was markedly increased compared with values from time-matched Sal-treated nonseptic rats. This change was associated with redistribution of eIF4E from the inactive eIF4E·4E-BP1 to the active eIF4E·eIF4G complex. In septic rats, Leu-induced phosphorylation of 4E-BP1 and changes in eIF4E distribution were completely abrogated. Sepsis also antagonized the Leu-induced increase in phosphorylation of S6 kinase 1 and ribosomal protein S6. Sepsis attenuated Leu-induced phosphorylation of mammalian target of rapamycin and eIF4G. The ability of sepsis to inhibit anabolic effects of Leu could not be attributed to differences in plasma concentrations of insulin, insulin-like growth factor I, or Leu between groups. In contrast, the ability of exogenous insulin-like growth factor I to stimulate the same signaling components pertaining to translation initiation was not impaired by sepsis. Hence, sepsis produces a relatively specific Leu resistance in skeletal muscle that impairs the ability of this amino acid to stimulate translation initiation and protein synthesis.

scholarly journals GIPC Participates in G Protein Signaling Downstream of Insulin-like Growth Factor 1 Receptor

2002 ◽  
Vol 277 (8) ◽  
pp. 6719-6725 ◽  
Author(s):  
Ronald A. Booth ◽  
Cathy Cummings ◽  
Mario Tiberi ◽  
X. Johné Liu
Keyword(s):  
Growth Factor ◽  
G Protein ◽  
G Protein Signaling ◽  
Insulin Like Growth Factor ◽  
Protein Signaling
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