Abstract
It has been shown that MDMX inhibits the activity of the tumor suppressor p53 by primarily cooperating with the p53 feedback regulator MDM2. Here, our study shows that this inhibition can be overcome by 14-3-3γ and Chk1. 14-3-3γ was identified as an MDMX-associated protein via an immuno-affinity purification-coupled mass spectrometry. Consistently, 14-3-3γ; directly interacted with MDMX in vitro, and this interaction was stimulated by MDMX phosphorylation in vitro and in cells. Interestingly, in response to UV irradiation, the wild-type, but not the kinase-dead mutant, Chk1 phosphorylated MDMX at serine 367, enhanced the 14-3-3γ-MDMX binding and the cytoplasmic retaining of MDMX. The Chk1 specific inhibitor UCN-01 repressed all of these effects. Moreover, overexpression of 14-3-3γ, but not its mutant K50E, which did not bind to MDMX, suppressed MDMX-enhanced p53 ubiquitination, leading to p53 stabilization and activation. Finally, ablation of 14-3-3γ by siRNA reduced UV-induced p53 level and G1 arrest. Thus, these results demonstrate 14-3-3γ and Chk1 as two novel regulators of MDMX in response to UV irradiation.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1207-1218 |
| Number of pages | 12 |
| Journal | EMBO Journal |
| Volume | 25 |
| Issue number | 6 |
| DOIs | |
| State | Published - Mar 22 2006 |
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Keywords
- 14-3-3γ
- Chk1
- MDMX
- p53
- UV response
ASJC Scopus subject areas
- Genetics
- Cell Biology
Cite this
14-3-3γ binds to MDMX that is phosphorylated by UV-activated Chk1, resulting in p53 activation. / Jin, Yetao; Dai, Mushui; Lu, Steven Z.; Xu, Yingda; Luo, Zhijun; Zhao, Yingming; Lu, Hua.
In: EMBO Journal, Vol. 25, No. 6, 22.03.2006, p. 1207-1218.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - 14-3-3γ binds to MDMX that is phosphorylated by UV-activated Chk1, resulting in p53 activation
AU - Jin, Yetao
AU - Dai, Mushui
AU - Lu, Steven Z.
AU - Xu, Yingda
AU - Luo, Zhijun
AU - Zhao, Yingming
AU - Lu, Hua
PY - 2006/3/22
Y1 - 2006/3/22
N2 - It has been shown that MDMX inhibits the activity of the tumor suppressor p53 by primarily cooperating with the p53 feedback regulator MDM2. Here, our study shows that this inhibition can be overcome by 14-3-3γ and Chk1. 14-3-3γ was identified as an MDMX-associated protein via an immuno-affinity purification-coupled mass spectrometry. Consistently, 14-3-3γ; directly interacted with MDMX in vitro, and this interaction was stimulated by MDMX phosphorylation in vitro and in cells. Interestingly, in response to UV irradiation, the wild-type, but not the kinase-dead mutant, Chk1 phosphorylated MDMX at serine 367, enhanced the 14-3-3γ-MDMX binding and the cytoplasmic retaining of MDMX. The Chk1 specific inhibitor UCN-01 repressed all of these effects. Moreover, overexpression of 14-3-3γ, but not its mutant K50E, which did not bind to MDMX, suppressed MDMX-enhanced p53 ubiquitination, leading to p53 stabilization and activation. Finally, ablation of 14-3-3γ by siRNA reduced UV-induced p53 level and G1 arrest. Thus, these results demonstrate 14-3-3γ and Chk1 as two novel regulators of MDMX in response to UV irradiation.
AB - It has been shown that MDMX inhibits the activity of the tumor suppressor p53 by primarily cooperating with the p53 feedback regulator MDM2. Here, our study shows that this inhibition can be overcome by 14-3-3γ and Chk1. 14-3-3γ was identified as an MDMX-associated protein via an immuno-affinity purification-coupled mass spectrometry. Consistently, 14-3-3γ; directly interacted with MDMX in vitro, and this interaction was stimulated by MDMX phosphorylation in vitro and in cells. Interestingly, in response to UV irradiation, the wild-type, but not the kinase-dead mutant, Chk1 phosphorylated MDMX at serine 367, enhanced the 14-3-3γ-MDMX binding and the cytoplasmic retaining of MDMX. The Chk1 specific inhibitor UCN-01 repressed all of these effects. Moreover, overexpression of 14-3-3γ, but not its mutant K50E, which did not bind to MDMX, suppressed MDMX-enhanced p53 ubiquitination, leading to p53 stabilization and activation. Finally, ablation of 14-3-3γ by siRNA reduced UV-induced p53 level and G1 arrest. Thus, these results demonstrate 14-3-3γ and Chk1 as two novel regulators of MDMX in response to UV irradiation.
KW - 14-3-3γ
KW - Chk1
KW - MDMX
KW - p53
KW - UV response
UR - http://www.scopus.com/inward/record.url?scp=33645293151&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33645293151&partnerID=8YFLogxK
U2 - 10.1038/sj.emboj.7601010
DO - 10.1038/sj.emboj.7601010
M3 - Article
VL - 25
SP - 1207
EP - 1218
JO - EMBO Journal
JF - EMBO Journal
SN - 0261-4189
IS - 6
ER -