Targeted silencing of Jab1/Csn5 in human cells downregulates SCF activity through reduction of F-box protein levels.
Targeted silencing of Jab1/Csn5 in human cells downregulates SCF activity through reduction of F-box protein levels.
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DOI：
10.1186/1471-2091-7-1
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发表时间：
2006-01-09
期刊：
影响因子：
--
通讯作者：
Deshaies RJ
中科院分区：
文献类型：
--
作者：
Cope GA;Deshaies RJ
SCF泛素连接酶靶向许多蛋白进行泛素依赖性蛋白水解，包括p27和细胞周期蛋白E。SCF和其他cullin-RING连接酶（CRL）由共价修饰cullin亚基的泛素样蛋白Nedd 8调节。Nedd 8的去除由Cop 9信号体的Csn 5亚基内的Jab 1/MPN结构域金属酶（JAMM）基序催化。在这里，我们有条件地敲低Csn 5表达在HEK 293人类细胞使用强力霉素诱导的shRNA系统。CSN缺陷的人类细胞中Cullin水平没有改变，但多种F-box蛋白的水平降低。分子分析表明，这种减少是由于Cul 1和蛋白酶体依赖性营业额增加。F-box水平降低导致SCF活性降低，这一点可以通过Csn 5缺失细胞中F-box蛋白Fbw 7的两种底物细胞周期蛋白E和c-myc的积累来证明。我们建议，cul 1的deneddylation需要通过抑制SCF复合物内的F-盒蛋白的“autoubiquitination”来维持SCF泛素连接酶的最佳活性，从而将它们从过早降解中拯救出来。
SCF ubiquitin ligases target numerous proteins for ubiquitin dependent proteolysis, including p27 and cyclin E. SCF and other cullin-RING ligases (CRLs) are regulated by the ubiquitin-like protein Nedd8 that covalently modifies the cullin subunit. The removal of Nedd8 is catalyzed by the Jab1/MPN domain metalloenzyme (JAMM) motif within the Csn5 subunit of the Cop9 Signalosome. Here, we conditionally knock down Csn5 expression in HEK293 human cells using a doxycycline-inducible shRNA system. Cullin levels were not altered in CSN-deficient human cells, but the levels of multiple F-box proteins were decreased. Molecular analysis indicates that this decrease was due to increased Cul1- and proteasome-dependent turnover. Diminished F-box levels resulted in reduced SCF activity, as evidenced by accumulation of two substrates of the F-box protein Fbw7, cyclin E and c-myc, in Csn5-depleted cells. We propose that deneddylation of Cul1 is required to sustain optimal activity of SCF ubiquitin ligases by repressing 'autoubiquitination' of F-box proteins within SCF complexes, thereby rescuing them from premature degradation.
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影响因子：
--
作者：
Cope GA;Deshaies RJ
通讯作者：
Deshaies RJ
影响因子：
64.8
作者：
Pintard, L;Willis, JH;Peter, M
通讯作者：
Peter, M
DOI：
10.1073/pnas.95.13.7451
发表时间：
1998-06-23
影响因子：
11.1
作者：
Lyapina, SA;Correll, CC;Deshaies, RJ
通讯作者：
Deshaies, RJ
影响因子：
11.6
作者：
Dohmann, EMN;Kuhnle, C;Schwechheimer, C
通讯作者：
Schwechheimer, C
影响因子：
7.7
作者：
van de Wetering, M;Oving, I;Clevers, H
通讯作者：
Clevers, H