Cell Signaling Technology

Product Pathways - PI3K / Akt Signaling

FoxO3a (75D8) Rabbit mAb #2497

Applications Reactivity Sensitivity MW (kDa) Isotype
W IF-IC H M R Mk Endogenous 82 to 97 Rabbit IgG

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

Protocols

Specificity / Sensitivity

FoxO3a (75D8) Rabbit mAb detects exogenous and endogenous levels of total FoxO3a protein. The antibody does not detect the exogenously expressed family members FoxO4 or FoxO1.

Source / Purification

Monoclonal antibody is produced by immunizing animals with a synthetic peptide corresponding to residues surrounding Glu50 of human FoxO3a.

Western Blotting

Western Blotting

Western blot analysis of extracts from wild type (+/+) and FoxO3 knock-out (-/-) mouse brain, using FoxO3a (75D8) Rabbit mAb (upper) and FoxO1 (C29H4) Rabbit mAb #2880 (lower). (FoxO3 knock-out (-/-) mouse brain was kindly provided by Dr. Ron DePinho, Dana-Farber Cancer Institute, Boston, MA).

Western Blotting

Western Blotting

Western blot analysis of extracts from Jurkat and PC3 cells using FoxO3a (75D8) Rabbit mAb.

IF-IC

IF-IC

Confocal immunofluorescent analysis of SH-SY5Y cells, IGF-I treated (left) or LY294002-treated, using FoxO3a (75D8) Rabbit mAb (green). Actin filaments have been labeled with Alexa Fluor® 555 phalloidin (red). Blue pseudocolor = DRAQ5® #4084 (fluorescent DNA dye).


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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Companion Products

Rabbit monoclonal antibody is produced under license (granting certain rights including those under U. S. Patent No. 5,675,063 and U.S.S.N. 11/476,277) from Epitomics, Inc.

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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