Histone H2A.X, phosphorylated (Ser139) (H2a/x, H2AFX, H2AX) (PE)

Histone H2A.X is a variant histone that represents approximately 10% of the total H2A histone proteins in normal human fibroblasts (1). H2A.X is required for checkpoint-mediated cell cycle arrest and DNA repair following double-stranded DNA breaks (1). DNA damage, caused by ionizing radiation, UV-light, or radiomimetic agents, results in rapid phosphorylation of H2A.X at Ser139 by PI3K-like kinases, including ATM, ATR, and DNA-PK (2,3). Within minutes following DNA damage, H2A.X is phosphorylated on Ser139 at sites of DNA damage (4). This very early event in the DNA-damage response is required for recruitment of a multitude of DNA-damage response proteins, including MDC1, NBS1, RAD50, MRE11, 53BP1, and BRCA1 (1). In addition to its role in DNA-damage repair, H2A.X is required for DNA fragmentation during apoptosis and is phosphorylated by various kinases in response to apoptotic signals. H2A.X is phosphorylated on Ser139 by DNA-PK in response to cell death receptor activation, c-Jun N-terminal Kinase (JNK1) in response to UV-A irradiation, and p38 MAPK in response to serum starvation (5-8). H2A.X is constitutively phosphorylated on Tyr142 in undamaged cells by WSTF (Williams-Beuren syndrome transcription factor) (9,10). Upon DNA damage, and concurrent with phosphorylation of Ser139, Tyr142 is dephosphorylated at sites of DNA damage by recruited EYA1 and EYA3 phosphatases (9). While phosphorylation of Ser139 facilitates the recruitment of DNA repair proteins and apoptotic proteins to sites of DNA damage, phosphorylation of Tyr142 appears to determine which set of proteins are recruited. Phosphorylation of H2A.X on Tyr142 inhibits the recruitment of DNA repair proteins and promotes binding of pro-apoptotic factors such as JNK1 (9). Mouse embryonic fibroblasts expressing only mutant H2A.X Y142F, which favors recruitment of DNA repair proteins over apoptotic proteins, show a reduced apoptotic response to ionizing radiation (9). Thus, it appears that the balance of H2A.X Tyr142 phosphorylation and dephosphorylation provides a switch mechanism to determine cell fate after DNA damage.\n\nApplications: \nSuitable for use in Flow Cytometry. Other applications not tested.\n\nRecommended Dilution:\nFlow Cytometry: 1:50\nOptimal dilutions to be determined by the researcher.\n\nStorage and Stability:\nMay be stored at 4 degrees C before opening. DO NOT FREEZE! Stable at 4 degrees C as an undiluted liquid. Dilute only prior to immediate use. Stable for at least 6 months at 4 degrees C. Freezing R-Phycoerythrin (PE) conjugates will result in a substantial loss of activity. PE conjugates are sensitive to light.

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SPECIFICATIONS

Catalog Number

H5110-03X

Size

100ul

Applications

FC

Hosts

Rabbit

Reactivities

Hum, Mouse, Rat, NHP

Form

Supplied as a liquid in in PBS, pH 7.2, <0.1% sodium azide, 2 mg/ml BSA. Labeled with R-Phycoerythrin (PE).

P Type

Mab

Purity

Supernatant

Isotype

IgG

References

1.Yuan, J. et al. (2010) FEBS Lett 584, 3717-24. 2.Rogakou, E.P. et al. (1998) J Biol Chem 273, 5858-68. 3.Burma, S. et al. (2001) J Biol Chem 276, 42462-7. 4.Rogakou, E.P. et al. (1999) J Cell Biol 146, 905-16. 5.Mukherjee, B. et al. (2006) DNA Repair (Amst) 5, 575-90. 6.Solier, S. et al. (2009) Mol Cell Biol 29, 68-82. 7.Lu, C. et al. (2006) Mol Cell 23, 121-32. 8.Lu, C. et al. (2008) FEBS Lett 582, 2703-8. 9.Cook, P.J. et al. (2009) Nature 458, 591-6. 10.Xiao, A. et al. (2009) Nature 457, 57-62.

Additional Info

Recognizes endogenous levels of human H2A.X, phosphorylated at Ser139. Species Crossreactivity: Monkey, mouse and rat.