Tau proteins: the molecular structure and mode of binding on microtubules.
Tau proteins: the molecular structure and mode of binding on microtubules.
复制标题
DOI：
10.1083/jcb.107.4.1449
复制
发表时间：
1988-10
期刊：
影响因子：
--
通讯作者：
Okabe S
中科院分区：
文献类型：
--
作者：
Hirokawa N;Shiomura Y;Okabe S
Tau是一个密切相关的蛋白质家族（55，000 - 62，000 mol wt），其包含在神经细胞中并与微管蛋白共聚以在体外诱导微管的形成。到目前为止，所有的信息都表明，tau蛋白与微管晶格紧密并列，并且没有迹象表明从微管聚合物晶格突出的结构域。我们用快速冷冻、深蚀法（QF.DE）和低角度旋转阴影技术研究了tau因子的分子结构及其与微管的结合方式。将磷酸纤维素柱纯化的猪脑微管蛋白与tau聚合，并通过QF. DE处理离心沉淀。我们观察到周期性的臂状元素（18.7 +/- 4.8 nm长）从微管表面突出。大多数的突起似乎交联相邻的微管。我们测量了微管上tau投射的纵向周期性，发现它与6-二聚体模式的匹配比12-二聚体模式的匹配更好。在tau饱和微管的制备物中tau与微管蛋白的化学计量为1：约5.0（摩尔比）。吸附在云母上的Tau分子呈现棒状形式（56.1 +/-14.1nm长）。虽然tau和MAP 1都包含在轴突中，竞争性结合研究表明，微管表面上的tau和MAP 1A的结合位点是最不同的，尽管它们可能部分重叠。
Tau is a family of closely related proteins (55,000-62,000 mol wt) which are contained in the nerve cells and copolymerize with tubulin to induce the formation of microtubules in vitro. All information so far has indicated that tau is closely apposed to the microtubule lattice, and there was no indication of domains projecting from the microtubule polymer lattice. We have studied the molecular structure of the tau factor and its mode of binding on microtubules using the quick-freeze, deep-etch method (QF.DE) and low angle rotary shadowing technique. Phosphocellulose column-purified tubulin from porcine brain was polymerized with tau and the centrifuged pellets were processed by QF.DE. We observed periodic armlike elements (18.7 +/- 4.8 nm long) projecting from the microtubule surface. Most of the projections appeared to cross-link adjacent microtubules. We measured the longitudinal periodicity of tau projections on the microtubules and found it to match the 6-dimer pattern better than the 12-dimer pattern. The stoichiometry of tau versus tubulin in preparations of tau saturated microtubules was 1:approximately 5.0 (molar ratio). Tau molecules adsorbed on mica took on rodlike forms (56.1 +/- 14.1 nm long). Although both tau and MAP1 are contained in axons, competitive binding studies demonstrated that the binding sites of tau and MAP1A on the microtubule surfaces are most distinct, although they may partially overlap.