Interaction of the pim1/spi1 mitotic checkpoint with a protein phosphatase.
Interaction of the pim1/spi1 mitotic checkpoint with a protein phosphatase.
复制标题
pim1/spi1 有丝分裂检查点与蛋白磷酸酶的相互作用。
DOI：
10.1091/mbc.4.3.337
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发表时间：
1993
影响因子：
3.3
通讯作者：
Beach,D
中科院分区：
文献类型：
--
作者：
Matsumoto,T;Beach,D
p58pim1是人类RCC1的同源物，其缺失会导致有丝分裂从DNA复制的完成中分离。pim1突变等位基因esp1的基因外抑制基因已被分离并鉴定。esp1编码305个氨基酸残基的预测产物，与出芽酵母SIT4（一种2a型相关蛋白磷酸酶）有71%的相似性。p58pim1结合p25spi1， p25spi1是一种25 kd的ras相关的GTPase，以前作为pim1的高剂量抑制剂被分离出来。该复合物在鸟嘌呤核苷酸和Mg2+的存在下解离。突变体p58pim1结合p25spi1的能力存在缺陷，这表明物理相互作用对于维持细胞周期事件的相互依赖性至关重要。在esp1 - pim1双突变体中，突变体p58pim1蛋白与p25spi1结合的能力仍然存在缺陷。然而，pmi1诱导的过早有丝分裂被完全抑制，这表明esp1可能作用于p58pim1/p25spi1物理相互作用的下游，而作用于m期特异性组蛋白H1激酶的激活的上游。
Loss of p58pim1, a homolog of human RCC1, results in uncoupling of mitosis from the completion of DNA replication in fission yeast. An extragenic suppressor of a mutant allele of pim1, esp1, has been isolated and characterized. esp1 encodes a predicted product of 305 amino acid residues, which shares 71% identity with budding yeast SIT4, a type2A related protein phosphatase. p58pim1 binds p25spi1, a 25-kd ras-related GTPase previously isolated as a high dosage suppressor of pim1. The complex dissociates in the presence of guanine nucleotides and Mg2+. The mutant p58pim1 is defective in its ability to bind p25spi1, suggesting that the physical interaction is essential for the maintenance of the interdependency of cell cycle event. In the esp1 pim1 double mutant, the mutant p58pim1 protein is still defective in its ability to bind to p25spi1. However, pmi1 induced premature mitosis is completely suppressed, suggesting that esp1 may act downstream of the p58pim1/p25spi1 physical interaction but upstream of the activation of the M-phase specific histone H1 kinase.