Critical role for p53-serine 15 phosphorylation in stimulating transactivation at p53-responsive promoters

Abstract

The p53 tumour suppressor is induced by various stress stimuli and coordinates an adaptive gene expression programme leading to growth arrest or cell death. Some stimuli, such as DNA damage, lead to rapid and substantial multisite phosphorylation of p53, nucleated initially through phosphorylation of serine 15. Other stimuli, such as hyper-proliferation, do not stimulate p53-phosphorylation, raising questions regarding the physiological role for phosphorylation. Here, we show that a basal level of Ser15 phosphorylation occurs in both unstimulated cells and cells stimulated pharmacologically to induce p53. p53 in which Ser15 is substituted by alanine (S15A) fails to mediate p53-dependent transcription or growth arrest but can be rescued by substitution with aspartate (S15D: a phospho-mimic). Chromatin immunoprecipitation (ChIP) analyses show that, while wt- and S15A-p53 are detectable on the CDKN1A (p21) promoter (as a representative p53-responsive promoter), S15A-p53 does not stimulate histone acetylation (a measure of chromatin relaxation), nor is its recruitment stimulated, in response to a DNA damage or pharmacological stimulus. These data demonstrate that Ser15 phosphorylation is required for p53 function in the physiological context of p53-responsive promoters and suggest a key and possibly universal role even for low levels of this modification in promoting p53-transcription function.

GD2 ganglioside specific antibody treatment downregulates PI3K/Akt/mTOR signaling network in human neuroblastoma cell lines

“…This finding is in agreement with our earlier results, showing that the mAb-induced cell death is only partially caused by apoptosis (8). P53 can be also phosphorylated at Ser15 by different kinases and thus impairs the ability of MDM2 to bind P53, promoting both the accumulation and activation of P53 in response to DNA damage (62). Our results allow us to hypothesize that P53 transcription function can be decreased.…”

Hydroxyl metabolite of PCB 180 induces DNA damage signaling and enhances the DNA damaging effect of benzo[a]pyrene

“…Neither PCB180 nor 3'-OH-PCB180 phosphorylated p53 Ser15 under our in vitro experimental conditions (data not shown). BaP, on the other hand, increased p53 Ser15 levels time dependently (data not shown), which is in line with previous work (Darzynkiewicz, Traganos et al 2011, Loughery, Cox et al 2014, Wang, Wu et al 2015. PCB180 did not induce γH2AX at any time point (Fig.…”

Deficiency in DNA damage response, a new characteristic of cells infected with latent HIV-1

“…50,51 p53 becomes activated in response to different stressors, but in the case of DNA damage, phosphorylation of Serine 15 on p53 is required to permit local acetylation of histones and relaxation of chromatin. [52][53][54][55] To determine whether this signaling pathway associated with DNA damage is activated in latently infected cells, we analyzed the levels of phosphorylated forms of ATM at Ser1981, Chk2 at Thr68 and p53 at Ser15 (Fig. 4).…”