Genetic analysis of the fimbrin-actin binding interaction in Saccharomyces cerevisiae.
Genetic analysis of the fimbrin-actin binding interaction in Saccharomyces cerevisiae.
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DOI：
10.1093/genetics/140.1.91
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发表时间：
1995-05
期刊：
影响因子：
3.3
通讯作者：
S. Brower;J. Honts;A. Adams
中科院分区：
文献类型：
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作者：
S. Brower;J. Honts;A. Adams
酵母fimplant由SAC6基因编码，其突变抑制肌动蛋白基因（ACT1）中的温度敏感性突变。为了研究抑制的机制，我们对17个sac6抑制等位基因进行了测序，发现它们改变了9个不同的残基，所有这些残基都聚集在Sac6p的两个肌动蛋白结合结构域之一的三个区域中。其中两个簇发生在高度保守的区域（ABS1和ABS3），这些区域与相关蛋白质与肌动蛋白的结合密切相关。第三个簇改变了以前不参与与肌动蛋白相互作用的残基。由于9个不同残基中的任何一个的变化都可以抑制几个不同的act1等位基因，因此很可能是抑制子恢复了Sac6p和肌动蛋白之间的整体亲和力，而不是特定的失去的相互作用。使用诱变，我们已经确定了两个突变的第二肌动蛋白结合结构域，也可以抑制act1突变的利益。这一结果表明Sac6p的两个肌动蛋白结合结构域与肌动蛋白分子的同一区域相互作用。然而，温度敏感性和孢子形成的抑制强度的差异表明，这两个肌动蛋白结合域是不同的，并解释了为什么第二个域的突变没有被确定以前。
Yeast fimbrin is encoded by the SAC6 gene, mutations of which suppress temperature-sensitive mutations in the actin gene (ACT1). To examine the mechanism of suppression, we have sequenced 17 sac6 suppressor alleles, and found that they change nine different residues, all of which cluster in three regions of one of the two actin-binding domains of Sac6p. Two of these clusters occur in highly conserved regions (ABS1 and ABS3) that have been strongly implicated in the binding of related proteins to actin. The third cluster changes residues not previously implicated in the interaction with actin. As changes in any of nine different residues can suppress several different act1 alleles, it is likely that the suppressors restore the overall affinity, rather than specific lost interactions, between Sac6p and actin. Using mutagenesis, we have identified two mutations of the second actin-binding domain that can also suppress the act1 mutations of interest. This result suggests the two actin-binding domains of Sac6p interact with the same region of the actin molecule. However, differences in strength of suppression of temperature-sensitivity and sporulation indicate that the two actin-binding domains are distinct, and explain why second-domain mutations were not identified previously.