Cell Signaling Technology

Product Pathways - MAPK Signaling

c-Fos Antibody #4384

Applications Reactivity Sensitivity MW (kDa) Source
W H M R Endogenous 62 Rabbit

Applications Key:  W=Western Blotting
Reactivity Key:  H=Human  M=Mouse  R=Rat
Species cross-reactivity is determined by Western blot.

Protocols

Specificity / Sensitivity

c-Fos Antibody detects endogenous levels of total c-Fos protein. The antibody does not cross-react with other Fos proteins, including FosB, FRA1 and FRA2.

Source / Purification

Polyclonal antibodies are produced by immunizing rabbits with a synthetic peptide (KLH-coupled) corresponding to amino acids near the carboxy-terminus of human c-Fos protein. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from HeLa, RAW, and H-4-IIE cells serum-starved overnight and TPA-stimulated for 4 hours, using c-Fos Antibody.

Background

The Fos family of nuclear oncogenes includes c-Fos, FosB, Fos-related antigen 1 (FRA1) and Fos-related antigen 2 (FRA2) (1). While most Fos proteins exist as a single isoform, the FosB protein exists as two isoforms: full-length FosB and a shorter form FosB2 (?FosB) that lacks the carboxy-terminal 101 amino acids (1,2). The expression of Fos proteins is rapidly and transiently induced by a variety of extracellular stimuli, including growth factors, cytokines, neurotransmitters, polypeptide hormones and stress. Fos proteins dimerize with Jun proteins (c-Jun, JunB and JunD) to form Activator Protein-1 (AP-1), a transcription factor that binds to TRE/AP-1 elements and activates transcription. Fos and Jun proteins contain the leucine-zipper motif that mediates dimerization and an adjacent basic domain that binds to DNA. The various Fos/Jun heterodimers differ in their ability to transactivate AP-1 dependent genes. In addition to increased expression, phosphorylation of Fos proteins by ERK kinases in response to extracellular stimuli may further increase transcriptional activity (4-6). Phosphorylation of c-Fos on serine 32 and threonine 232 by ERK-5 increases protein stability and nuclear localization (5). Phosphorylation of FRA1 on serines 252 and 265 by ERK-1/2 increases protein stability and leads to over-expression of FRA1 in cancer cells (6). Expression of FosB and c-Fos in quiescent fibroblasts after growth factor stimulation is immediate, but very short-lived, with protein levels dissipating after several hours (7). However, FRA1 and FRA2 expression persists longer and appreciable levels can be detected in asynchronously growing cells (8). Deregulated expression of c-Fos, FosB, or FRA2 can result in neoplastic cellular transformation; however, FosB2 lacks the ability to transform cells (2,3).

  1. Tulchinsky, E. (2000) Histol. Histopathol. 15, 921-928.
  2. Dobrzanski, P. et al. (1991) Mol. Cell. Biol. 11, 5470-5478.
  3. Nakabeppu, Y. and Nathans, D. (1991) Cell 64, 751-759.
  4. Rosenberger, S.F. et al. (1999) J. Biol. Chem. 274, 1124-1130.
  5. Sasaki, T. et al. (2006) Mol. Cell 24, 63-75.
  6. Basbous, J. et al. (2007) Mol. Cell. Biol. 27, 3936-3950.
  7. Kovary, K. and Bravo, R. (1991) Mol. Cell. Biol. 11, 2451-2459.
  8. Kovary, K. and Bravo, R. (1992) Mol. Cell. Biol. 12, 5015-5023 .

Application References

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Companion Products

This product is for in vitro research use only and is not intended for use in humans or animals. This product is not intended for use as therapeutic or in diagnostic procedures.

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