Regulatory ATPase sites of cytoplasmic dynein affect processivity and force generation.
Regulatory ATPase sites of cytoplasmic dynein affect processivity and force generation.
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DOI：
10.1074/jbc.m802951200
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发表时间：
2008-09-19
期刊：
影响因子：
--
通讯作者：
Vale RD
中科院分区：
文献类型：
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作者：
Cho C;Reck-Peterson SL;Vale RD
细胞质动力蛋白的重链含有四个称为AAA 1-AAA 4的核苷酸结合结构域，其中第一个结构域（AAA 1）是主要的ATP水解位点。尽管之前的研究已经提出了AAA 3和AAA 4的调节作用，但ATP水解在这些位点的作用仍然难以捉摸。在这里，我们分析了单分子运动特性的酵母细胞质动力蛋白突变体轴承突变，防止ATP水解AAA 3或AAA 4。这两种突变体都保持了持续性，但AAA 4突变体由于其对微管的更紧密的亲和力而表现出惊人的持续性增加。除了运动特性的变化，AAA 3和AAA 4突变体产生的最大力低于野生型动力蛋白。这些结果表明，在AAA 3和AAA 4的核苷酸结合状态可以变构调节微管结合亲和力，影响动力蛋白的持续合成能力和力的产生。
The heavy chain of cytoplasmic dynein contains four nucleotide-binding domains referred to as AAA1–AAA4, with the first domain (AAA1) being the main ATP hydrolytic site. Although previous studies have proposed regulatory roles for AAA3 and AAA4, the role of ATP hydrolysis at these sites remains elusive. Here, we have analyzed the single molecule motility properties of yeast cytoplasmic dynein mutants bearing mutations that prevent ATP hydrolysis at AAA3 or AAA4. Both mutants remain processive, but the AAA4 mutant exhibits a surprising increase in processivity due to its tighter affinity for microtubules. In addition to changes in motility characteristics, AAA3 and AAA4 mutants produce less maximal force than wild-type dynein. These results indicate that the nucleotide binding state at AAA3 and AAA4 can allosterically modulate microtubule binding affinity and affect dynein processivity and force production.