A microtubule-binding domain in dynactin increases dynein processivity by skating along microtubules
A microtubule-binding domain in dynactin increases dynein processivity by skating along microtubules
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DOI：
10.1038/ncb1370
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发表时间：
2006-03-01
影响因子：
21.3
通讯作者：
King, SJ
中科院分区：
文献类型：
--
作者：
Culver-Hanlon, TL;Lex, SA;King, SJ
微管相关蛋白 (MAP) 使用特定的微管结合域，使其能够以特定于其个体细胞功能的方式与微管相互作用。在这里，我们在 dynactin 的 p150 亚基中鉴定出了一个高度碱性的微管结合域，该结构域仅存在于 CAP-Gly 蛋白家族的 dynactin 成员中。使用单颗粒微管结合测定，我们发现动力蛋白的基本结构域在没有分子马达的情况下沿着微管逐渐移动——我们称之为“滑行”的过程。相比之下，先前描述的 dynactin 的 CAP-Gly 结构域仍然牢固地附着在微管上的单个点上。进一步的分析表明，微管滑行是一种沿着微管的一维扩散形式。为了确定滑冰现象的细胞功能，在单分子运动测定中检查了动力蛋白和动力蛋白微管结合域。我们发现基本结构域将动力蛋白的持续合成能力提高了四倍，而 CAP-Gly 结构域则抑制了动力蛋白的运动性。我们的数据表明，动力蛋白利用动力蛋白基本结构域沿微管滑动的能力，在每次与微管相遇时维持更长的相互作用。
Microtubule-associated proteins (MAPs) use particular microtubule-binding domains that allow them to interact with microtubules in a manner specific to their individual cellular functions. Here, we have identified a highly basic microtubule-binding domain in the p150 subunit of dynactin that is only present in the dynactin members of the CAP-Gly family of proteins. Using single-particle microtubule-binding assays, we found that the basic domain of dynactin moves progressively along microtubules in the absence of molecular motors - a process we term 'skating'. In contrast, the previously described CAP-Gly domain of dynactin remains firmly attached to a single point on microtubules. Further analyses showed that microtubule skating is a form of one-dimensional diffusion along the microtubule. To determine the cellular function of the skating phenomenon, dynein and the dynactin microtubule-binding domains were examined in single-molecule motility assays. We found that the basic domain increased dynein processivity fourfold whereas the CAP-Gly domain inhibited dynein motility. Our data show that the ability of the basic domain of dynactin to skate along microtubules is used by dynein to maintain longer interactions for each encounter with microtubules.