UBIQUITIN DEPENDENCE OF SELECTIVE PROTEIN-DEGRADATION DEMONSTRATED IN THE MAMMALIAN-CELL CYCLE MUTANT TS85
UBIQUITIN DEPENDENCE OF SELECTIVE PROTEIN-DEGRADATION DEMONSTRATED IN THE MAMMALIAN-CELL CYCLE MUTANT TS85
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DOI：
10.1016/0092-8674(84)90300-3
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发表时间：
1984-01-01
期刊：
影响因子：
64.5
通讯作者：
VARSHAVSKY, A
中科院分区：
文献类型：
--
作者：
CIECHANOVER, A;FINLEY, D;VARSHAVSKY, A
在小鼠[乳腺癌FM3A]细胞周期突变体ts85中，泛素与蛋白质的共价结合是温度敏感的，这是由于一种特异性热不稳定的泛素活化酶（随附论文）。与野生型和回复突变体细胞相反，ts85中短寿命蛋白的降解也是温度敏感的。在允许温度下，ts85和野生型细胞中> 70%的预标记的异常蛋白质（含有氨基酸类似物）或嘌呤霉素肽在4小时内降解，而在非允许温度下，ts85细胞中<15%的蛋白质或嘌呤霉素肽降解。在ts85细胞和野生型细胞中，异常蛋白质和嘌呤霉素肽的降解是非溶酶体和ATP依赖性的。免疫化学分析表明，在非允许温度下，在ts85细胞中，体内标记的泛素-蛋白质缀合物的水平强烈而特异性地降低。在ts85中，正常的短寿命蛋白质的降解也是温度敏感的。在这种高等真核细胞中，不依赖于泛素的途径对短寿命蛋白质降解的贡献不超过10%，甚至可能更少。
Covalent conjugation of ubiquitin to proteins is temperature-sensitive in the mouse [mammary carcinoma FM3A] cell cycle mutant ts85, due to a specifically thermolabile ubiquitin-activating enzyme (accompanying paper). Degradation of short-lived proteins is also temperature sensitive in ts85, in contrast to wild-type and revertant cells. While > 70% of the prelabeled abnormal proteins (containing amino acid analogs) or puromycyl peptides are degraded within 4 h at the permissive temperature in both ts85 and wild-type cells, < 15% are degraded in ts85 cells at the nonpermissive temperature. Degradation of abnormal proteins and puromycyl peptides, in both ts85 cells and wild-type cells, is nonlysosomal and ATP-dependent. Immunochemical analysis shows a strong and specific reduction in the levels of in vivo labeled ubiquitin-protein conjugates at the nonpermissive temperature, in ts85 cells. Degradation of normal, short-lived proteins is also specifically temperature sensitive in ts85. The contribution of ubiquitin-independent pathways to the degradation of short-lived proteins in this higher eukaryotic cell is no more than 10%, and possibly less.