Cell Signaling Technology

Product Pathways - MAPK Signaling

FosB (5G4) Rabbit mAb #2251

FBJ murine osteosarcoma viral oncogene homolog B   fos   GOS3   GOSB   sc-48  

No. Size Price
2251S 100 µl ( 10 western blots ) ¥3,250.00 现货查询 购买询价
2251T 20 µl ( 2 western blots ) ¥1,200.00 现货查询 购买询价
2251 carrier free & custom formulation / quantityemail request
Applications Dilution Species-Reactivity Sensitivity MW (kDa) Isotype
W 1:1000 Human,Mouse,Rat, Endogenous 38 FosB2 48 FosB Rabbit IgG
IP 1:50
IHC-P 1:50
F 1:200
IF-IC 1:800
ChIP 1:50

Species cross-reactivity is determined by western blot.

Applications Key: W=Western Blotting, IP=Immunoprecipitation, IHC-P=Immunohistochemistry (Paraffin), F=Flow Cytometry, IF-IC=Immunofluorescence (Immunocytochemistry), ChIP=Chromatin IP,

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.

FosB (5G4) Rabbit mAb 兔单抗能检测内源性总FosB 蛋白水平(FosB、FosB2 两种亚型)。该抗体不能与其他FosB 蛋白发生交叉反应,包括c-fos, FRA1、FRA2。

Source / Purification

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

该单克隆抗体通过使用与人源FosB 蛋白序列相一致的合成肽段免疫动物而获得。

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 HeLa cells control (left) or PMA-treated (right), 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).

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).



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.


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).

细胞核原癌基因的Fos家族成员包括c-Fos、FosB、Fos-相关抗原1 (FRA1)、Fos-相关抗原2 (FRA2)。虽然大部分Fos蛋白以单一亚型存在,但是FosB蛋白以两种亚型存在:全长的FosB蛋白和缩短的形式——FosB2 (Delta FosB),后者缺乏羧端的101个氨基酸(1-3)。Fos蛋白的表达是由细胞外刺激子快速且瞬间诱导的,这些刺激因子包括生长因子、细胞因子、神经传导物质、多肽激素和应激反应。Fos蛋白和Jun蛋白(c-Jun, JunB, 和JunD)结合成二聚体形成活化因子蛋白-1 (AP-1),它是结合到TRE/AP-1元件上的转录因子,并且能激活转录。Fos、Jun蛋白包含一个亮氨酸拉链基序,能调节二聚化和结合DNA的一个毗邻碱性域。各种Fos/Jun二聚体的不同点在于反式激活AP-1依赖性基因的能力。Fos蛋白对细胞外刺激因子应答后,除了表达量增加,同时也被Erk蛋白磷酸化,它的磷酸化可能会进一步增强转录活性(4-6)。Erk5蛋白引起的c-Fos蛋白丝氨酸(32位点)和苏氨酸(232位点)磷酸化增强了蛋白质稳定性和核定位(5)。Erk1/2引起的FRA1蛋白丝氨酸(252、265位点)磷酸化增强了蛋白稳定性,导致癌细胞内FRA1蛋白的过量表达(6)。生长因子刺激后,相对静止的成纤维细胞中FosB、c-Fos蛋白表达在短时间内接近蛋白水平,但是几个小时后就消失了(7)。FRA1、 FRA2的表达持续时间更长,而且在异步生长细胞中能检测到它的相对水平(8)。c-Fos, FosB, 和FRA2的失控表达将导致细胞的癌变;然而Delta FosB蛋白能阻止这种细胞转化的能力(2,3)。

  1. Tulchinsky, E. (2000) Histol Histopathol 15, 921-8.
  2. Dobrazanski, P. et al. (1991) Mol Cell Biol 11, 5470-8.
  3. Nakabeppu, Y. and Nathans, D. (1991) Cell 64, 751-9.
  4. Rosenberger, S.F. et al. (1999) J Biol Chem 274, 1124-30.
  5. Sasaki, T. et al. (2006) Mol Cell 24, 63-75.
  6. Basbous, J. et al. (2007) Mol Cell Biol 27, 3936-50.
  7. Kovary, K. and Bravo, R. (1991) Mol Cell Biol 11, 2451-9.
  8. Kovary, K. and Bravo, R. (1992) Mol Cell Biol 12, 5015-23.

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