Cell Signaling Technology

Product Pathways - PI3K / Akt Signaling

Phospho-FoxO3a (Ser413) (D77C9) Rabbit mAb #8174

Applications Reactivity Sensitivity MW (kDa) Isotype
W IP H Endogenous 82-97 Rabbit IgG

Applications Key:  W=Western Blotting  IP=Immunoprecipitation
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-FoxO3a (Ser413) (D77C9) Rabbit mAb recognizes endogenous levels of FoxO3a protein only when phosphorylated at Ser413. This antibody does not cross-react with FoxO1 or FoxO4 proteins.

Source / Purification

Monoclonal antibody is produced by immunizing animals with a synthetic peptide corresponding to residues surrounding Ser413 of human FoxO3a protein.

Western Blotting

Western Blotting

Western blot analysis of extracts from 293T cells transfected with FoxO3a, untreated (-) or treated with λ phosphatase (+), using Phospho-FoxO3a (Ser413) (D77C9) Rabbit mAb (upper) and FoxO3a (75D8) Rabbit mAb #2497 (lower).

Western Blotting

Western Blotting

Western blot analysis of extracts from SH-SY5Y cells, untreated, MG132-treated, H2O2-treated or AICAR-treated, using Phospho-FoxO3 (Ser413) (D77C9) Rabbit mAb (upper) and FoxO3a (75D8) Rabbit mAb #2497 (lower).

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).

AMPK phosphorylates FoxO3a at Ser413 amongst other sites. While this phosphorylation event does not alter the localization of FoxO3a, it leads to activation and transcriptional activity of target genes such as Gadd45a (10).

  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.
  10. Greer, E.L. et al. (2007) J Biol Chem 282, 30107-30119.

Application References

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

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