Cell cycle-regulated degradation of Xenopus cyclin B2 requires binding to p34cdc2.
Cell cycle-regulated degradation of Xenopus cyclin B2 requires binding to p34cdc2.
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非洲爪蟾细胞周期蛋白 B2 的细胞周期调节降解需要与 p34cdc2 结合。
DOI：
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发表时间：
1994
影响因子：
3.3
通讯作者：
M. Lohka
中科院分区：
文献类型：
--
作者：
H. M. van der Velden;M. Lohka
细胞周期调节因子p34cdc2的蛋白激酶活性在其结合的有丝分裂周期蛋白被降解时失活。有丝分裂周期蛋白的氨基末端包括一个保守的“破坏盒”序列，这是降解所必需的。虽然海胆细胞周期蛋白B的n端赋予融合蛋白细胞周期调节的降解，但只含有爪蟾细胞周期蛋白B2的n端（包括破坏盒）的截断蛋白在全长分子降解的条件下是稳定的。为了鉴定除破坏盒外的细胞周期蛋白B2参与降解的区域，我们检测了非洲爪蟾卵提取物中细胞周期蛋白B2 c端缺失突变体编码的蛋白质的稳定性。只有前90个氨基酸的截断周期蛋白是稳定的，但缺少14到187个氨基酸的其他c端缺失是不稳定的，并且通过一种既不受细胞周期调节也不依赖于破坏盒的机制被降解。没有c端缺失突变体结合p34cdc2。为了研究p34cdc2的结合是否需要细胞周期调节降解，我们检测了一系列全长Xenopus cyclin B2 cDNA编码的蛋白的行为，这些蛋白在p34cdc2结合域的保守氨基酸上发生了点突变。所有的点突变体都不能与p34cdc形成稳定的复合物，与野生型cyclin相比，它们的降解明显降低。当在网织细胞裂解物中合成突变细胞周期蛋白和在爪蟾卵提取物中直接翻译细胞周期蛋白mRNA时，获得了类似的结果。这些结果表明，干扰p34cdc2结合的突变也会干扰细胞周期蛋白的破坏，这表明p34cdc2结合是细胞周期调节的Xenopus细胞周期蛋白B2破坏所必需的。
The protein kinase activity of the cell cycle regulator p34cdc2 is inactivated when the mitotic cyclin to which it is bound is degraded. The amino (N)-terminus of mitotic cyclins includes a conserved "destruction box" sequence that is essential for degradation. Although the N-terminus of sea urchin cyclin B confer cell cycle-regulated degradation to a fusion protein, a truncated protein containing only the N-terminus of Xenopus cyclin B2, including the destruction box, is stable under conditions where full length molecules are degraded. In an attempt to identify regions of cyclin B2, other than the destruction box, involved in degradation, the stability of proteins encoded by C-terminal deletion mutants of cyclin B2 was examined in Xenopus egg extracts. Truncated cyclin with only the first 90 amino acids was stable, but other C-terminal deletions lacking between 14 and 187 amino acids were unstable and were degraded by a mechanism that was neither cell cycle regulated nor dependent upon the destruction box. None of the C-terminal deletion mutants bound p34cdc2. To investigate whether the binding of p34cdc2 is required for cell cycle-regulated degradation, the behavior of proteins encoded by a series of full length Xenopus cyclin B2 cDNA with point mutations in conserved amino acids in the p34cdc2-binding domain was examined. All of the point mutants failed to form stable complexes with p34cdc, and their degradation was markedly reduced compared to wild-type cyclin. Similar results were obtained when the mutant cyclins were synthesized in reticulocyte lysates and when cyclin mRNA was translated directly in a Xenopus egg extract. These results indicate that mutations that interfere with p34cdc2 binding also interfere with cyclin destruction, suggesting that p34cdc2 binding is required for the cell cycle-regulated destruction of Xenopus cyclin B2.
甲基化泛素抑制蛤胚提取物中细胞周期蛋白的降解。
DOI：
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发表时间：
1991
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Hershko,A;Ganoth,D;Pehrson,J;Palazzo,RE;Cohen,LH
通讯作者：
Cohen,LH