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 ChIP 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  ChIP=Chromatin IP
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).


Chromatin IP

Chromatin IP

Chromatin immunoprecipitations were performed with cross-linked chromatin from 4 x 106 PC-12 cells starved overnight and treated with β-NGF #5221 (50 ng/ml) for 2 hr and either 10 μl of FosB (5G4) Rabbit mAb or 2 μl of Normal Rabbit IgG #2729 using SimpleChIP® Enzymatic Chromatin IP Kit (Magnetic Beads) #9003. The enriched DNA was quantified by real-time PCR SimpleChIP® Rat CCRN4L Promoter Primers #7983, rat DCLK1 promoter primers, and SimpleChIP® Rat GAPDH Promoter Primers #7964. The amount of immunoprecipitated DNA in each sample is represented as signal relative to the total amount of input chromatin, which is equivalent to one.

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.

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

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