Cell Signaling Technology

Product Pathways - DNA Damage

p53 (1C12) Mouse mAb (Alexa Fluor® 647 Conjugate) #2533

Applications Reactivity Sensitivity Isotype
IF-IC F H M R Mk Endogenous Mouse IgG1

Applications Key:  IF-IC=Immunofluorescence (Immunocytochemistry)  F=Flow Cytometry
Reactivity Key:  H=Human  M=Mouse  R=Rat  Mk=Monkey
Species cross-reactivity is determined by western blot. Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Protocols

Specificity / Sensitivity

p53 (1C12) Mouse mAb (Alexa Fluor® 647 Conjugate) detects endogenous levels of total p53 protein.

Source / Purification

Monoclonal antibody is produced by immunizing animals with a synthetic peptide corresponding to residues surrounding Ser20 of human p53. The antibody was conjugated to Alexa Fluor® 647 under optimal conditions with an F/P ratio of 2-6. The Alexa Fluor® 647 dye is maximally excited by red light (e.g. 633 nm He-Ne laser). Antibody conjugates of the Alexa Fluor® 647 dye produce bright far-red-fluorescence emission, with a peak at 665 nm.

Flow Cytometry

Flow Cytometry

Flow cytometric analysis of K562 (blue) and HT-29 (green) cells using p53 (1C12) Mouse mAb (Alexa Fluor® 647 Conjugate).

IF-IC

IF-IC

Confocal immunofluorescent analysis of HT-29 cells, untreated (left) and UV-treated (right), using p53 (1C12) Mouse mAb (Alexa Fluor® 647 Conjugate) (blue pseudocolor). Actin filaments have been labeled with DY-554 phalloidin (red).

Description

This Cell Signaling Technology antibody is conjugated to Alexa Fluor® 647 fluorescent dye and tested in-house for direct flow cytometry and immunofluorescent analysis in human and mouse cells. The antibody is expected to exhibit the same species cross-reactivity as the unconjugated p53 (1C12) Mouse mAb #2524.

Background

The p53 tumor suppressor protein plays a major role in cellular response to DNA damage and other genomic aberrations. Activation of p53 can lead to either cell cycle arrest and DNA repair or apoptosis (1). p53 is phosphorylated at multiple sites in vivo and by several different protein kinases in vitro (2,3). DNA damage induces phosphorylation of p53 at Ser15 and Ser20 and leads to a reduced interaction between p53 and its negative regulator, the oncoprotein MDM2 (4). MDM2 inhibits p53 accumulation by targeting it for ubiquitination and proteasomal degradation (5,6). p53 can be phosphorylated by ATM, ATR, and DNA-PK at Ser15 and Ser37. Phosphorylation impairs the ability of MDM2 to bind p53, promoting both the accumulation and activation of p53 in response to DNA damage (4,7). Chk2 and Chk1 can phosphorylate p53 at Ser20, enhancing its tetramerization, stability, and activity (8,9). p53 is phosphorylated at Ser392 in vivo (10,11) and by CAK in vitro (11). Phosphorylation of p53 at Ser392 is increased in human tumors (12) and has been reported to influence the growth suppressor function, DNA binding, and transcriptional activation of p53 (10,13,14). p53 is phosphorylated at Ser6 and Ser9 by CK1δ and CK1ε both in vitro and in vivo (13,15). Phosphorylation of p53 at Ser46 regulates the ability of p53 to induce apoptosis (16). Acetylation of p53 is mediated by p300 and CBP acetyltransferases. Inhibition of deacetylation suppressing MDM2 from recruiting HDAC1 complex by p19 (ARF) stabilizes p53. Acetylation appears to play a positive role in the accumulation of p53 protein in stress response (17). Following DNA damage, human p53 becomes acetylated at Lys382 (Lys379 in mouse) in vivo to enhance p53-DNA binding (18). Deacetylation of p53 occurs through interaction with the SIRT1 protein, a deacetylase that may be involved in cellular aging and the DNA damage response (19).

  1. Levine, A.J. (1997) Cell 88, 323-331.
  2. Meek, D.W. (1994) Semin. Cancer Biol. 5, 203-210.
  3. Milczarek, G.J. et al. (1997) Life Sci. 60, 1-11.
  4. Shieh, S.Y. et al. (1997) Cell 91, 325-334.
  5. Chehab, N.H. et al. (1999) Proc. Natl. Acad. Sci. USA 96, 13777-13782.
  6. Honda, R. et al. (1997) FEBS Lett. 420, 25-27.
  7. Tibbetts, R.S. et al. (1999) Genes Dev. 13, 152-157.
  8. Shieh, S.Y. et al. (1999) EMBO J. 18, 1815-1823.
  9. Hirao, A. et al. (2000) Science 287, 1824-1827.
  10. Hao, M. et al. (1996) J. Biol. Chem. 271, 29380-29385.
  11. Lu, H. et al. (1997) Mol. Cell. Biol. 17, 5923-5934.
  12. Ullrich, S.J. et al. (1993) Proc. Natl. Acad. Sci. USA 90, 5954-5958.
  13. Kohn, K.W. (1999) Mol. Biol. Cell 10, 2703-2734.
  14. Lohrum, M. and Scheidtmann, K.H. (1996) Oncogene 13, 2527-2539.
  15. Knippschild, U. et al. (1997) Oncogene 15, 1727-1736.
  16. Oda, K. et al. (2000) Cell 102, 849-862.
  17. Ito, A. et al. (2001) EMBO J. 20, 1331-1340.
  18. Sakaguchi, K. et al. (1998) Genes Dev. 12, 2831-2841.
  19. Solomon, J.M. et al. (2006) Mol. Cell. Biol. 26, 28-38.

Application References

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

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