Cell Signaling Technology

Product Pathways - MAPK Signaling

FosB (5G4) Rabbit mAb #2251

Applications Reactivity Sensitivity MW (kDa) Isotype
W IP IHC-P IF-IC F H M R Endogenous 38 FosB2 48 FosB Rabbit IgG

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

Protocols

Specificity / Sensitivity

FosB (5G4) Rabbit mAb detects endogenous levels of total FosB protein (both FosB and FosB2 isoforms). The antibody does not cross-react with other Fos proteins, including c-fos, FRA1 and FRA2.

Source / Purification

Monoclonal antibody is produced by immunizing animals with a synthetic peptide corresponding to the sequence of human FosB.

Western Blotting

Western Blotting

Western blot analysis of extracts from HeLa cells serum-starved overnight and TPA-stimulated for 4 hours, or NIH/3T3 cells and C6 cells serum-starved overnight and serum-stimulated for 4 hours, using FosB (5G4) Rabbit mAb.

IHC-P (paraffin)

IHC-P (paraffin)

Immunohistochemical analysis of paraffin-embedded human breast carcinoma, using FosB (5G4) Rabbit mAb.

IHC-P (paraffin)

IHC-P (paraffin)

Immunohistochemical analysis of paraffin-embedded human breast carcinoma, using FosB (5G4) Rabbit mAb in the presence of control peptide (left) or FosB Blocking Peptide #1042 (right).


IHC-P (paraffin)

IHC-P (paraffin)

Immunohistochemical analysis of paraffin-embedded HeLa cells control (left) or PMA-treated (right), using FosB (5G4) Rabbit mAb.

Flow Cytometry

Flow Cytometry

Flow cytometric analysis of HeLa cells, untreated (blue) or TPA treated (green), using FosB (5G4) Rabbit mAb compared to a nonspecific negative control antibody (red).

IF-IC

IF-IC

Confocal immunofluorescent analysis of HeLa cells either serum-starved (left) or TPA-treated (right) and labeled with FosB (5G4) Rabbit mAb (green). Actin filaments have been labeled with Alexa Fluor® 555 phalloidin (red).


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 (Delta FosB), that lacks the carboxy-terminal 101 amino acids (1-3). 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 at Ser32 and Thr232 by Erk5 increases protein stability and nuclear localization (5). Phosphorylation of FRA1 at Ser252 and Ser265 by Erk1/2 increases protein stability and leads to overexpression of FRA1 in cancer cells (6). Following growth factor stimulation, expression of FosB and c-Fos in quiescent fibroblasts is immediate, but very short-lived, with protein levels dissipating after several hours (7). 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, Delta FosB 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

Rabbit Monoclonals Produced Using Epitomics® Technology, U.S. Patent No. 5,675,063.

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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