Cell Signaling Technology

Product Pathways - PI3K / Akt Signaling

Phospho-FoxO1 (Ser319) Antibody #2486

Applications Reactivity Sensitivity MW (kDa) Source
W H Transfected Only 120 (GFP-FoxO1) Rabbit

Applications Key:  W=Western Blotting
Reactivity Key:  H=Human
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-FoxO1 (Ser319) Antibody detects exogenous levels of FoxO1 only when phosphorylated at serine 319. The antibody does not cross-reacts with FoxO1 phosphorylated at other sites nor with other phosphorylated family members.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Ser319 of human FoxO1. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from untreated or serum-treated COS-7 cells exogenously expressing GFP-FoxO1, using Phospho-FoxO1 (Ser319) Antibody. The phospho-specificity of the antibody was verified by treating the membrane with (+) or without (-) calf intestinal phosphatase (CIP) after Western transfer.

Western Blotting

Western Blotting

Western blot analysis of extracts from serum-treated COS-7 cells untransfected, exogenously expressing FoxO4 or GFP-FoxO1, using Phospho-FoxO1 (Ser319) (left) or Phospho-FoxO1 (Ser319)/FoxO4 (Ser262) Antibody #2487 (right).

Background

The Forkhead family of transcription factors is involved in tumorigenesis of rhabdomyosarcoma and acute leukemias (1-3). Within the family, three members (FoxO1, FoxO4, and FoxO3a) have sequence similarity to the nematode orthologue DAF-16, which mediates signaling via a pathway involving IGFR1, PI3K, and Akt (4-6). Active forkhead members act as tumor suppressors by promoting cell cycle arrest and apoptosis. Increased expression of any FoxO member results in the activation of the cell cycle inhibitor p27 Kip1. Forkhead transcription factors also play a part in TGF-β-mediated upregulation of p21 Cip1, a process negatively regulated through PI3K (7). Increased proliferation results when forkhead transcription factors are inactivated through phosphorylation by Akt at Thr24, Ser256, and Ser319, which results in nuclear export and inhibition of transcription factor activity (8). Forkhead transcription factors can also be inhibited by the deacetylase sirtuin (SirT1) (9).

  1. Anderson, M.J. et al. (1998) Genomics 47, 187-199.
  2. Galili, N. et al. (1993) Nat. Genet. 5, 230-235.
  3. Borkhardt, A. et al. (1997) Oncogene 14, 195-202.
  4. Nakae, J. et al. (1999) J. Biol. Chem. 274, 15982-15985.
  5. Rena, G. et al. (1999) J. Biol. Chem. 274, 17179-17183.
  6. Guo, S. et al. (1999) J. Biol. Chem. 274, 17184-17192.
  7. Seoane, J. et al. (2004) Cell 117, 211-223.
  8. Arden, K.C. (2004) Mol. Cell 14, 416-418.
  9. Yang, Y. et al. (2005) EMBO J. 24, 1021-1032.

Application References

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This product is intended for research purposes only. The product is not intended to be used for therapeutic or diagnostic purposes in humans or animals.

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