Effect of sepsis on eIE4E availability in skeletal muscle.
Chronic septic abscess formation causes an inhibition of protein synthesis in gastrocnemius that is not observed in rats with a sterile abscess. The inhibition is associated with an impaired translation initiation. The present study was designed to investigate the effects of sepsis on phosphorylation and availability of eukaryotic initiation factor (eIF)4E in gastrocnemius 5 days after induction of a sterile or septic abscess. Neither sepsis nor sterile inflammation altered the extent of eIF4E phosphorylation. Moreover, no changes in the amount of the binding protein 4E-BP1 associated with eIF4E or in the phosphorylation of 4E-BP1 were observed during sepsis or sterile inflammation. In contrast, sepsis and sterile inflammation caused a reduction in the relative amount of eIF4G bound to eIF4E compared with controls. The diminished amount of eIF4G bound to eIF4E was not the result of a reduced abundance of eIF4E. Sepsis, but not sterile inflammation, caused an increase in the cellular abundance of eIF4E. The results provide evidence that alterations in the eIF4E system are probably not rate controlling for the synthesis of total, mixed proteins in gastrocnemius during sepsis. Instead, on the basis of our previous studies, changes in eIF2B appear to be responsible for limiting protein synthesis in skeletal muscle during sepsis.
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Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA.tvary@psu.edu
Kimball
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D000818:Animals; D002352:Carrier Proteins; D039561:Eukaryotic Initiation Factor-4E; D007163:Immunosorbent Techniques; D007249:Inflammation / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010448:Peptide Initiation Factors / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D018805:Sepsis / Q000378:metabolism*
D002352:Carrier Proteins; C499526:Eif4ebp1 protein, rat; D039561:Eukaryotic Initiation Factor-4E; D047908:Intracellular Signaling Peptides and Proteins; D010448:Peptide Initiation Factors; D010750:Phosphoproteins