Cell Signaling Technology

Product Pathways - MAPK Signaling

FosB (5G4) Rabbit mAb (Alexa Fluor® 488 Conjugate) #2023

Applications Reactivity Sensitivity Isotype
F H M R Endogenous Rabbit IgG

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

Protocols

Specificity / Sensitivity

FosB (5G4) Rabbit mAb (Alexa Fluor® 488 Conjugate) 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. The antibody was conjugated to Alexa Fluor® 488 under optimal conditions with an F/P ratio of 2-6.

Flow Cytometry

Flow Cytometry

Flow cytometric analysis of HeLa cells, untreated (blue) or treated with TPA (green), using FosB (5G4) Rabbit mAb (Alexa Fluor® 488 Conjugate).

Description

This Cell Signaling Technology antibody is conjugated to Alexa Fluor® 488 fluorescent dye and tested in-house for direct flow cytometric analysis of human cells. The unconjugated antibody FosB (5G4) Rabbit mAb #2251 reacts with human, mouse and rat FosB protein. CST expects that FosB (5G4) Rabbit mAb (Alexa Fluor® 488 Conjugate) will also recognize FosB in these species.

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 (1,2). 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

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

Alexa Fluor® is a registered trademark of Molecular Probes, Inc.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.

Products