Characterization of SIS1, a Saccharomyces cerevisiae homologue of bacterial dnaJ proteins.
Characterization of SIS1, a Saccharomyces cerevisiae homologue of bacterial dnaJ proteins.
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DOI：
10.1083/jcb.114.4.623
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发表时间：
1991-08
期刊：
影响因子：
--
通讯作者：
Arndt KT
中科院分区：
文献类型：
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作者：
Luke MM;Sutton A;Arndt KT
酿酒酵母SIS1基因是含有SIT4基因突变的菌株的慢生长表型的高拷贝抑制因子，SIT4基因编码预测的丝氨酸/苏氨酸蛋白磷酸酶。SIS1蛋白在氨基末端的三分之一和羧基末端的三分之一上与细菌的dna J蛋白相似。相反，SIS1的中间三分之一与dna J蛋白不同。SIS1的这个区域包含一个甘氨酸/蛋氨酸富集区，以及更多的氨基末端序列，这是SIS1与一个表观分子质量为40kD的蛋白质结合所必需的。SIS1基因是必不可少的。限制SIS1蛋白的菌株积累的细胞似乎阻止了细胞核从母细胞迁移到子细胞。此外，许多细胞变得非常大，并含有一个大的液泡。SIS1蛋白定位于整个细胞，但更集中在细胞核。在核糖核酸酶处理后，大约四分之一的SIS1蛋白从细胞核中释放出来。我们还发现，另一种与细菌dna J蛋白相似的酵母蛋白YDJ1的过度表达不能取代SIS1。
The Saccharomyces cerevisiae SIS1 gene was identified as a high copy number suppressor of the slow growth phenotype of strains containing mutations in the SIT4 gene, which encodes a predicted serine/threonine protein phosphatase. The SIS1 protein is similar to bacterial dnaJ proteins in the amino-terminal third and carboxyl-terminal third of the proteins. In contrast, the middle third of SIS1 is not similar to dnaJ proteins. This region of SIS1 contains a glycine/methionine-rich region which, along with more amino-terminal sequences, is required for SIS1 to associate with a protein of apparent molecular mass of 40 kD. The SIS1 gene is essential. Strains limited for the SIS1 protein accumulate cells that appear blocked for migration of the nucleus from the mother cell into the daughter cell. In addition, many of the cells become very large and contain a large vacuole. The SIS1 protein is localized throughout the cell but is more concentrated at the nucleus. About one- fourth of the SIS1 protein is released from a nuclear fraction upon treatment with RNase. We also show that overexpression of YDJ1, another yeast protein with similarity to bacterial dnaJ proteins, can not substitute for SIS1.