PMID- 16920842 OWN - NLM STAT- MEDLINE DCOM- 20061005 LR - 20230216 IS - 0022-3166 (Print) IS - 0022-3166 (Linking) VI - 136 IP - 9 DP - 2006 Sep TI - Meal feeding stimulates phosphorylation of multiple effector proteins regulating protein synthetic processes in rat hearts. PG - 2284-90 AB - Feeding promotes protein synthesis in cardiac muscle through a stimulation of the mRNA translation initiation phase of protein synthesis either secondary to nutrient-induced rises in insulin or because of direct effects of nutrients themselves. The present set of experiments establishes the effects of meal feeding on the potential signal transduction pathways that may be important in accelerating mRNA translation initiation. Hearts were obtained from male Sprague Dawley rats that had been trained to consume a meal consisting of nonpurified diet prior to, during, and following the test meal. Meal feeding raised the extent of phosphorylation of eukaryotic initiation factor (eIF)4G (Ser(1108)), which returned to basal levels within 3 h of removal of food. Likewise, meal feeding was associated with an increase in phosphorylation of eIF4E binding protein-1(4EBP1) in the gamma-form during feeding. Phosphorylation of mammalian target of rapamycin (mTOR) on Ser(2448) or Ser(2481) or 70-kDa ribosomal protein S6 kinase (S6K1) on Thr(389) was not affected by meal feeding or following removal of food. Likewise, the extent of phosphorylation of TSC2, a potential upstream regulator of mTOR, was not significantly altered during meal feeding. Phosphorylation of protein kinase B (PKB) (Thr(308)) was elevated at all time points after initiating meal feeding. Similarly, the phosphorylation of protein kinase C(PKC)-epsilon but not PKC-delta was elevated at all time points after initiating meal feeding. We conclude from these studies that meal feeding stimulates at least 2 signal pathways in cardiac muscle that raises phosphorylation of eIF4G and 4EBP1 during meal feeding and results in sustained increases in phosphorylation of PKB and PKC-epsilon. FAU - Vary, Thomas C AU - Vary TC AD - Department of Cellular and Molecular Physiology, Penn State University College of Medicine, Hershey, PA 17033, USA. tvary@psu.edu FAU - Lynch, Christopher J AU - Lynch CJ LA - eng GR - AA-12814/AA/NIAAA NIH HHS/United States GR - DK-053843/DK/NIDDK NIH HHS/United States GR - DK-062880/DK/NIDDK NIH HHS/United States GR - GM-39277/GM/NIGMS NIH HHS/United States PT - Journal Article PT - Research Support, N.I.H., Extramural PL - United States TA - J Nutr JT - The Journal of nutrition JID - 0404243 RN - 0 (Carrier Proteins) RN - 0 (Eif4ebp1 protein, rat) RN - 0 (Eukaryotic Initiation Factor-4G) RN - 0 (Intracellular Signaling Peptides and Proteins) RN - 0 (Phosphoproteins) RN - EC 2.7.- (Protein Kinases) RN - EC 2.7.1.1 (mTOR protein, rat) RN - EC 2.7.11.1 (Proto-Oncogene Proteins c-akt) RN - EC 2.7.11.1 (Ribosomal Protein S6 Kinases) RN - EC 2.7.11.1 (TOR Serine-Threonine Kinases) RN - EC 2.7.11.13 (Protein Kinase C-delta) RN - EC 2.7.11.13 (Protein Kinase C-epsilon) SB - IM MH - Animals MH - Carrier Proteins/metabolism MH - Eukaryotic Initiation Factor-4G/metabolism MH - *Food MH - Intracellular Signaling Peptides and Proteins MH - Kinetics MH - Male MH - Myocardium/*metabolism MH - Phosphoproteins/*metabolism MH - Phosphorylation MH - Protein Biosynthesis/*physiology MH - Protein Kinase C-delta/metabolism MH - Protein Kinase C-epsilon/metabolism MH - Protein Kinases/metabolism MH - Proto-Oncogene Proteins c-akt/metabolism MH - Rats MH - Rats, Sprague-Dawley MH - Ribosomal Protein S6 Kinases MH - Signal Transduction MH - TOR Serine-Threonine Kinases EDAT- 2006/08/22 09:00 MHDA- 2006/10/06 09:00 CRDT- 2006/08/22 09:00 PHST- 2006/08/22 09:00 [pubmed] PHST- 2006/10/06 09:00 [medline] PHST- 2006/08/22 09:00 [entrez] AID - S0022-3166(22)08434-6 [pii] AID - 10.1093/jn/136.9.2284 [doi] PST - ppublish SO - J Nutr. 2006 Sep;136(9):2284-90. doi: 10.1093/jn/136.9.2284.