The cell senescence inducing gene product MORF4 is regulated by degradation via the ubiquitin/proteasome pathway.
The cell senescence inducing gene product MORF4 is regulated by degradation via the ubiquitin/proteasome pathway.
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DOI：
10.1016/j.yexcr.2009.09.015
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发表时间：
2010-01-01
影响因子：
3.7
通讯作者：
Pereira-Smith OM
中科院分区：
文献类型：
--
作者：
Tominaga K;Tominaga E;Ausserlechner MJ;Pereira-Smith OM
在经历几轮分裂后，正常人成纤维细胞进入称为细胞或复制性衰老的终末非分裂状态。我们克隆了MORF 4（人类4号染色体上的死亡因子），作为细胞衰老诱导基因，其导致分配到互补组B的无限分裂的永生细胞停止分裂。为了便于分析这种基因，这是有毒的细胞在低水平，我们获得了稳定的克隆表达四环素诱导的MORF4构建体，可以诱导强力霉素以剂量依赖性的方式的HeLa细胞。如先前观察到的，在培养14天后，M0RF 4诱导导致集落形成减少。我们确定MORF 4蛋白是不稳定的，并且蛋白酶体抑制剂MG 132的添加导致蛋白质的积累。除去MG132后，蛋白质迅速降解。MG132处理后的亚细胞分级分离表明，蛋白质主要在细胞质中积累，细胞核中存在一些量。因此，在细胞质中逃避降解的M0RF 4蛋白可能被转运到其发挥功能的细胞核。结果表明，细胞中MORF 4的水平必须严格控制，其中一个机制涉及蛋白质的稳定性。
After undergoing several rounds of divisions normal human fibroblasts enter a terminally non-dividing state referred to as cellular or replicative senescence. We cloned MORF4 (mortality factor on human chromosome 4), as a cellular senescence inducing gene that caused immortal cells assigned to complementation group B for indefinite division to stop dividing. To facilitate analyses of this gene, which is toxic to cells at low levels, we obtained stable clones of HeLa cells expressing a tetracycline-induced MORF4 construct that could be induced by doxycycline in a dose-dependent manner. MORF4 induction resulted in reduced colony formation after 14 days of culture, as previously observed. We determined that MORF4 protein was unstable and that addition of the proteasome inhibitor MG132 resulted in accumulation of the protein. Following removal of MG132 the protein was rapidly degraded. Subcellular fractionation following MG132 treatment demonstrated that the protein accumulates primarily in the cytoplasm with some amounts present in the nucleus. It is therefore possible that MORF4 protein, which escapes degradation in the cytoplasm, is transported to the nucleus where it is functional. The results suggest that levels of MORF4 in cells must be tightly controlled and one mechanism involves stability of the protein.
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DOI：
10.1073/pnas.92.20.9363
发表时间：
1995-09-26
影响因子：
11.1
作者：
DIMRI, GP;LEE, XH;CAMPISI, J
通讯作者：
CAMPISI, J
影响因子：
3.7
作者：
HAYFLICK, L;MOORHEAD, PS
通讯作者：
MOORHEAD, PS
影响因子：
3.9
作者：
Grillari, J;Hohenwarter, O;Katinger, H
通讯作者：
Katinger, H
影响因子：
3.9
作者：
Husom, AD;Peters, EA;Ferrington, DA
通讯作者：
Ferrington, DA
影响因子：
3.4
作者：
Louie, JL;Kapphahn, RJ;Ferrington, DA
通讯作者：
Ferrington, DA