IndraLab

"Here we show that the direct association between a p53 n-terminal peptide and mdm2 is disrupted by phosphorylation of the peptide on thr(18) but not by phosphorylation at other n-terminal sites, including ser(15) and ser(37). Thr(18) was phosphorylated in vitro by casein kinase (ck1)."

"CHK1 and CHK2 phosphorylate the p53 N terminus at Ser15, Thr18, Ser20, and Ser37"

"A cell-free ser(20) phosphorylation site assay was used to identify a broad range of calcium calmodulin kinase superfamily members, including chk2, chk1, dapk-1, dapk-3, drak-1, and ampk, as ser(20) kinases.Evaluation of these calcium calmodulin kinase superfamily members as candidate ser(20) kinases in vivo has shown that only chk1 or dapk-1 can stimulate p53 transactivation and induce ser(20) phosphorylation of p53."

"Dual-specificity phosphatase 26 is a novel p53 phosphatase and inhibits p53 tumor suppressor functions in human neuroblastoma|Inhibiting DUSP26 expression in the IMR-32 neuroblastoma cell line enhanced doxorubicin-induced p53 phosphorylation at Ser20 and Ser37, p21, Puma, Bax expression as well as apoptosis"

"The tumour suppressor protein p53 is stabilised and activated in response to ionising radiation. This is known to depend on the kinase atm;recent results suggest atm acts via the downstream kinase chk2/hcds1, which stabilises p53 at least in part by direct phosphorylation of residue serine 20"

"These findings strongly suggest that jnks are the major direct signaling mediators of uvb-induced p53 phosphorylation at serine 20. furthermore, phosphorylation of p53 at serine 20 by uvb-activated jnks and uvb-induced p53-dependent transcriptional activity were suppressed in jnk1 or jnk2 knockout (jnk1(-/-) or jnk2(-/-)) cells."

"These findings strongly suggest that jnks are the major direct signaling mediators of uvb-induced p53 phosphorylation at serine 20. furthermore, phosphorylation of p53 at serine 20 by uvb-activated jnks and uvb-induced p53-dependent transcriptional activity were suppressed in jnk1 or jnk2 knockout (jnk1(-/-) or jnk2(-/-)) cells."

"A cell-free ser(20) phosphorylation site assay was used to identify a broad range of calcium calmodulin kinase superfamily members, including chk2, chk1, dapk-1, dapk-3, drak-1, and ampk, as ser(20) kinases.Evaluation of these calcium calmodulin kinase superfamily members as candidate ser(20) kinases in vivo has shown that only chk1 or dapk-1 can stimulate p53 transactivation and induce ser(20) phosphorylation of p53."

"Although the stabilization of p53 was apparently concordant with its phosphorylation on N-terminal serine residues in HFFF-2 cells, it did not require the phosphorylation of Ser15 or Ser20 by ATM, a cellular kinase known to phosphorylate and promote the stabilization of p53 in response to DNA damage."

"Here, we demonstrate for the first time that cdk5 interacts with p53 and increases its stability through posttranslational regulation, leading to accumulation of p53, particularly in the nucleus. We show that cdk5 phosphorylates p53 on ser15, ser33 and ser46 in vitro,"

"Serine 20 phosphorylation of p53 has been shown to be required for the activation of p53 following UV radiation. we determined the role of map kinases in uvb-induced phosphorylation and found that jnks are directly involved in the phosphorylation of p53 at serine 20"

"Genetic and biochemical studies have shown that ser20 phosphorylation in the transactivation domain of p53 mediates p300-catalyzed dna-dependent p53 acetylation and b-cell tumor suppression. a cell-free ser20 phosphorylation site assay was used to identify a broad range of calcium calmodulin kinase superfamily members, including chk2, chk1, dapk-1, dapk-3, drak-1, and ampk, as ser20 kinases."

"The increased interaction between B56gamma and p53 after DNA damage requires ATM-dependent phosphorylation of p53 at Ser15."

"We found that dusp26 promotes the resistance of human neuroblastoma to doxorubicin-induced apoptosis by acting as a p53 phosphatase to downregulate p53 tumor suppressor function in neuroblastoma cells. / we found that dusp26 binds to p53 and dephosphorylates p53 at ser20 and ser37."

"DeltaNp63alpha depletion by RNAi reduces steady-state ATM mRNA and protein levels, and attenuates p53 Serine-15 phosphorylation. Conversely, ectopic expression of DeltaNp63alpha in p63-null tumour cells stimulates ATM transcription and p53 Serine-15 phosphorylation"

"Protein kinase ck1 is a p53-threonine 18 kinase which requires prior phosphorylation of serine 15."

"Upon exposure of cells to hydrogen peroxide (h(2)o(2)) phosphorylation of p53 was rapidly induced in human fibroblast gm00637, and this phosphorylation occurred on serine 9, serine 15, serine 20, but not on serine 392. In addition, h(2)o(2)-induced phosphorylation of p53 was followed by induction of p21, suggesting functional activation of p53. Ectopic expression of a plk3 dominant negative mutant, plk3(k52r), in gm00637 cells suppressed h(2)o(2)-induced serine 20 phosphorylation. Taken together, our studies strongly suggest that the oxidative stress-induced activation of p53 is at least in part mediated by plk3."