Cell Signaling Technology

Product Pathways - PI3K / Akt Signaling

Phospho-FoxO1 (Ser256) Antibody #9461

Applications Reactivity Sensitivity MW (kDa) Source
W H M R Mk (C) (Z) Endogenous 82 Rabbit

Applications Key:  W=Western Blotting
Reactivity Key:  H=Human  M=Mouse  R=Rat  Mk=Monkey  C=Chicken  Z=Zebrafish
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-Fox01 (Ser256) Antibody detects endogenous levels of Fox01 only when phosphorylated at serine 256. The antibody cross-reacts with Fox04 phosphorylated at Ser193.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic phosphopeptide corresponding to residues around Ser256 of human Fox01. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from COS cells, serum starved or serum treated, using Phospho-Fox01 (Ser256) Antibody.

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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