Cell Signaling Technology

Product Pathways - Translational Control

Phospho-eIF4G (Ser1108) Antibody #2441

Applications Reactivity Sensitivity MW (kDa) Source
W IP IF-IC H M R Hm Mk B Endogenous 220 Rabbit

Applications Key:  W=Western Blotting  IP=Immunoprecipitation  IF-IC=Immunofluorescence (Immunocytochemistry)
Reactivity Key:  H=Human  M=Mouse  R=Rat  Hm=Hamster  Mk=Monkey  B=Bovine
Species cross-reactivity is determined by western blot. Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Protocols

Specificity / Sensitivity

Phospho-eIF4G (Ser1108) Antibody detects eIF4GI only when phosphorylated at Ser1108. It does not cross-react with nonphosphorylated eIF4GI or p97.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Ser1108 of human eIF4GI. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from 293 cells expressing GST-eIF4GI Ser1192Ala or GST-eIF4GI Ser1108Ala mutant protein, using Phospho-eIF4G (Ser1108) Antibody. (Provided by Brian Raught, McGill University, Montreal, QuŽbec.)

Western Blotting

Western Blotting

Western blot analysis of extracts from PC12 cells, untreated (lane 1), NGF-treated (10 ng/ml) (lane 2), anisomycin-treated (25 µM) (lane 3), U0126-treated #9903 (10 µM) (lane 4), Rapamycin-treated #9904 (100 nM ) (lane 5) or LY294002-treated #9901 (25 µM) (lane 6), using Phospho-eIF4G (Ser1108) Antibody.

IF-IC

IF-IC

Confocal immunofluorescent analysis of HeLa cells either rapamycin-treated (left) or serum-treated (right), using Phospho-eIF4G (Ser1108) Antibody (green). Actin filaments have been labeled with Alexa Fluor® 555 phalloidin (red). Blue pseudocolor = DRAQ5™ (fluorescent DNA dye).


Background

Eukaryotic initiation factor 4E (eIF4E) binds to the mRNA cap structure to mediate the initiation of translation (1,2). eIF4E interacts with eIF4G, a scaffold protein that promotes assembly of eIF4E and eIF4A into the eIF4F complex (2). eIF4B is thought to assist the eIF4F complex in translation initiation. Upon activation by mitogenic and/or stress stimuli mediated by Erk and p38 MAPK, Mnk1 phosphorylates eIF4E at Ser209 in vivo (3,4). Two Erk and p38 MAPK phosphorylation sites in mouse Mnk1 (Thr197 and Thr202) are essential for Mnk1 kinase activity (3). The carboxy-terminal region of eIF4G also contains serum-stimulated phosphorylation sites, including Ser1108, Ser1148, and Ser1192 (5). Phosphorylation at these sites is blocked by the PI3 kinase inhibitor LY294002 and by the FRAP/mTOR inhibitor rapamycin.

  1. Sonenberg, N. et al. (1978) Proc. Natl. Acad. Sci. USA 75, 4843-4847.
  2. Gingras, A.C. et al. (1999) Annu. Rev. Biochem. 68, 913-963.
  3. Waskiewicz, A. et al. (1999) Mol. Cell. Biol. 19, 1871-1880.
  4. Pyronnet, S. et al. (1999) EMBO J. 18, 270-279.
  5. Raught, B. et al. (2000) EMBO J. 19, 434-444.

Application References

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For Research Use Only. Not For Use In Diagnostic Procedures.

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