Protein Synthesis Initiation Factor 4E [pS209], Pos/Neg Control Peptides (eIF 4E, Eukaryotic Transla

Eukaryotic initiation factor 4E (eIF4E) binds to the mRNA cap structure, thereby mediating the initiation of translation (1,2). eIF4E interacts with eIF4G, which serves as a scaffold protein for the assembly of eIF4E and eIF4A to form the eIF4F complex (2). Upon activation by mitogenic and/or stress stimuli mediated by Erk and p38 MAPK, Mnk1 has been shown to phosphorylate eIF4E at Ser209 in vivo (3,4). Two Erk and p38 MAPK phosphorylation sites have been identified in mouse Mnk1, Thr197 and Thr202, which are essential for Mnk1 kinase activity (3). The C-terminal region of eIF4G also contains serum-stimulated phosphorylation sites, including Ser1108, Ser1148 and Ser1192 (5). It is known that their phosphorylation is blocked by the PI3 kinase inhibitor LY294002 and by the FRAP/mTOR inhibitor rapamycin. Peptide Content: 80 ± 4%/80 ± 4% , Solubility/Reconstitution: We recommend that each vial be briefly centrifuged prior to opening to bring the contents to the bottom. To reconstitute the peptides, pipette 100ml sterile, distilled H2O into each vial. The peptides may be gently vortexed or triturated at RT to ensure complete solubilization. If the peptides are found to be slow to dissolve, the pH of the solutions may be neutralized by addition of small volumes (1-2 _L) 1.0 N ammonium hydroxide, alternatively, the peptides may be solubilized by addition of small volumes of organic solvent, such as ethanol or DMSO. Storage and Stability: Lyophilized powder may be stored at 4°C for short-term only. Stable for 12 months at -20°C. Reconstitute to nominal volume (see reconstitution instructions for peptides) and store at -20°C. For maximum recovery of product, centrifuge the original vial prior to removing the cap. Further dilutions can be made in assay buffer.