Cell Signaling Technology

Product Pathways - Akt Signaling

FoxO3a Antibody #9467

Applications Reactivity MW (kDa) Source
W IP IHC-P H Mk (M) (R) 82 to 97 Rabbit

Applications Key:  W=Western Blotting  IP=Immunoprecipitation  IHC-P=Immunohistochemistry (Paraffin)
Reactivity Key:  H=Human  M=Mouse  R=Rat  Mk=Monkey
Species enclosed in parentheses are predicted to react based on 100% sequence homology. Species cross-reactivity is determined by Western blot.

Specificity / Sensitivity

The Fox03a Antibody detects exogenous and endogenous levels of total Fox03a protein. The antibody does not detect the exogenously expressed family members Fox04 or Fox01. The antibody reacts with denatured components of bovine serum including BSA.

Source / Purification

Polyclonal antibodies are produced by immunizing rabbits with a synthetic peptide (KLH-coupled) derived from the sequence of human Fox03a. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from COS cells, mock transfected (lane 1), transfected with Fox04 (lane 2), transfected with Fox01 (lane 3), or transfected with Fox03a (lane 4), using Fox03a Antibody.

IHC-P (paraffin)

IHC-P (paraffin)

Immunohistochemical analysis of paraffin-embedded human colon carcinoma, using Fox03a Antibody in the presence of control peptide (left) or antigen-specific peptide (right).

IHC-P (paraffin)

IHC-P (paraffin)

Immunohistochemical analysis of paraffin-embedded human lung carcinoma, showing nuclear and cytoplasmic localization, using Fox03a Antibody.


IHC-P (paraffin)

IHC-P (paraffin)

Immunohistochemical analysis of paraffin-embedded human prostate carcinoma, using Fox03a 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 p27Kip1. Forkhead transcription factors also play a part in TGF-β-mediated upregulation of p21CIP1, 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).

In Fox03a, the three sites phosphorylated by Akt mentioned above are Thr32, Ser253 and Ser315. Fox03a associates with 14-3-3 proteins upon phosphorylation by Akt and is retained in the cytoplasm. In the absence of survival factors, Fox03a is dephosphorylated, translocates to the nucleus and triggers cell death by a Fas ligand-dependent mechanism (7).

  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

Have you published research involving the use of our products? If so we'd love to hear about it. Please let us know!

Companion Products

Product Pathways

Drug Discovery Tools

Featured Technologies

Protein Classes