c-Fos, mouse monoclonal, Cat# MCA-2H2

c-Fos, mouse monoclonal, Cat# MCA-2H2

Left: MCA-2H2 staining (green) in HeLa cells, which were treated with serum-starvation for 36 hours, followed by 2 hours, 20% FBS stimulation (bottom panel), or PBS treatment (top panel). Green c-Fos staining only localizes in the nuclei of stimulated cells, but not in un-stimulated cells. Cells are counter-stained with our chicken polyclonal antibody against vimentin, CPCA-Vim, in red). Blue shows DAPI staining of nucleus.Middle: Mouse brain section (45 μM; fixed by transcardial perfusion with 4% paraformaldehyde) labeled with MCA-2H2 using a standard HRP-DAB (horseradish peroxidase-3,3’-diaminobenzidine) staining technique. Cells expressing c-Fos show dark color in nucleus. Right: Mouse cortical section labeled with MCA-2H2 (red) and our rabbit polyclonal anti Fox3/NeuN (RPCA-Fox3) antibody (green) using immuno-fluorescent confocal-microscopy. Neurons positive for c-Fos and Fox3/NeuN appear to be yellow. Inset shows an enlarged image of MCA-2H2 staining. Nuclei are labeled with Dapi (blue). For more images of MCA-2H2 and also our rabbit antibody to c-Fos on stimulated and non-stimulated cells and tissues press here. For details of our rabbit polyclonal antibody to c-Fos, check out RPCA-c-Fos-AP.

Top panel: Western blot analysis of c-Fos expression in HeLa cells using MCA-2H2. Lane 1: HeLa cells were serum-starved for 36 hours. 2: Serum-starved HeLa cells were stimulated with 20% FBS (fetal bovine serum) for 2 hours. MCA-2H2 recognizes bands in the range of 50-65 kDa, which represent multiple forms of c-Fos. Serum starvation attenuates c-Fos expression, while 20% FBS strongly stimulates c-Fos expression. Bottom panel: Blot was stripped and probed with our monoclonal antibody against GAPDH, MCA-1D4, used as loading control.

Product name Anti-c-Fos
Description Mouse monoclonal antibody to c-Fos
Reference Code MCA-2H2
RRID# AB_2571561
Molecular weight 40.7 kDa (runs on SDS PAGE at 50-65 kDa)
Immunogen Full length recombinant human protein expressed in and purified from E. coli.
Isotype IgG1
Concentration Antibody is supplied as an aliquot of 1 mg/mL of affinity purified antibody.
Species Reactivity Human, horse, cow, pig, rat, mouse
Applications Western blot, ICC/IF, IHC
Suggestions for use Western blots: 1:1,000-2,000, ICC/IF or IHC: 1:1,000

The c-Fos protein is a member of Fos family of transcription factors and is a cellular counterpart of the retroviral oncogene v-Fos. Other members of Fos family are FosB, Fra-1 and Fra-2. The Fos proteins associate with Jun proteins, but also with other basic leucine zipper (bZIP) domain proteins to create a variety of AP-1 (activator protein-1) complexes which bind to the promoters of numerous genes (1). Dimeric complex of these AP-1 transcription factors activate generally rapid physiological processes such as cell proliferation, differentiation, neoplastic transformation, apoptosis, and response to stress.

c-Fos and c-Jun are the best-studied AP-1 components and both contain bZIP motifs, necessary for binding to DNA and dimerization. c-Fos and c-Jun containing AP-1 dimers activate transcription in combination with coactivators, such as the CREB-binding protein and constituents of the basal transcription machinery, such as the TATA-binding protein (3, 4).

c-Fos is considered to be an immediate-early gene because expression is normally low but induced rapidly and transiently in response to a wide array of stimuli including serum, growth factors, tumor promoters, cytokines, and UV radiation. This allows cells to rapidly turn on specific genes to adapt to environmental changes. It plays an important role in many cellular functions, and is over-expressed in a variety of cancers.

c-Fos is subjected to many different post translational modifications. Phosphorylation activates c-Fos, whereas sumoylation of c-Fos inhibits the AP-1 transcriptional activity (5, 6). Several lines of data demonstrate that expression of c-Fos in individual neurons can be used as a marker for neuronal activity, as there is an association between c-Fos expression and the firing of action potentials (7,8,9,10). Such work is usually done on histological sections of brain tissue and can be used to trace neuroanatomical connections, identify seizure pathways, and the sites of action of neuroactive drugs (8). Our MCA-2H2 antibody is proven to be an excellent reagent for these purposes.

MCA-2H2 was generated against full length human recombinant c-Fos protein expressed in and purified from E. coli. The HGNC name for this protein is FOS.


1. Mildle-Langosch K. The Fos family of transcription factors and their role in tumourigenesis. European Journal of Cancer 41:2449-2461 (2005)..

2. Chiu R, Boyle WJ, Meek J, Smeal T, Hunter T, Karin M. The c-Fos protein interacts with c-Jun/AP-1 to stimulate transcription of AP-1 responsive genes. Cell 54:541–52 (1988).

3. Bannister AJ and Kouzarides T. CBP-induced stimulation of c-Fos activity is abrogated by ElA. The EMBO Journal 14:4758-4762 (1995).

4. Metz R, Bannister AJ, Sutherland JA, Hagemeier C, O’Rourke EC, Cook A, Bravo R, Kouzarides T. c-Fos-induced activation of a TATA-box-containing promoter involves direct contact with TATA-box-binding protein. Mol Cell Biol. 14:6021-9 (1994).

5. Karin M. The regulation of AP-1 activity by mitogen activated protein kinases. J Biol Chem. 270:16483-6 (1995).

6. Bossis G, Malnou CE, Farras R, Andermarcher E, Hipskind R, Rodriguez M, Schmidt D, Muller S, Jariel-Encontre I, Piechaczyk M. Down-regulation of c-Fos/c-Jun AP-1 dimer activity by sumoylation. Mol Cell Biol.25(16):6964-79 (2005).

7. Day HE, Kryskow EM, Nyhuis TJ, Herlihy L, Campeau S. Conditioned Fear Inhibits c-fos mRNA Expression in the Central Extended Amygdala. Brain Res.1229: 137–46 (2008).

8. Hoffman G, Smith MS, Verbalis JG. c-Fos and related immediate early gene products as markers of activity in neuroendocrine systems. Fronties in Neuroendocrinology 14:173-213 (1993).

9. Van Elzakker M, Fevurly RD, Breindel T, Spencer RL. Environmental novelty is associated with a selective increase in Fos expression in the output elements of the hippocampal formation and the perirhinal cortex. Learn. Mem. 15: 899–908 (2008).

10. Dragunow M, Faull R. The use of c-fos as a metabolic marker in neuronal pathway tracing. Journal of Neuroscience Methods 29:261–265 (1989).

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