Identification of a novel microtubule binding and assembly domain in the developmentally regulated inter-repeat region of tau.
Identification of a novel microtubule binding and assembly domain in the developmentally regulated inter-repeat region of tau.
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在发育调节的tau的重复区域中，新型微管结合和组装结构域的鉴定。
DOI：
10.1083/jcb.124.5.769
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发表时间：
1994-03
影响因子：
7.8
通讯作者：
Feinstein, S C
中科院分区：
文献类型：
--
作者：
Goode, B L;Feinstein, S C
Tau是一种发育调节的微管相关蛋白，通过直接与微管蛋白结合来影响微管行为。tau蛋白的羧基末端含有多个18个氨基酸的重复序列，这些重复序列与微管结合，并被先前认为起“接头”作用的13-14个氨基酸的重复序列间（IR）区域隔开。“在这里，我们对tau进行了高分辨率的缺失分析，并将位于重复序列1和2之间的IR区域（R1-R2 IR）确定为独特的微管结合位点，其结合亲和力是任何单个重复序列的两倍以上。截短分析和定点诱变揭示了该位点的结合活性主要来自lys 265和lys 272，lys 271的贡献较小。这些结果预测了R1-R2 IR和微管蛋白之间的强的、离散的静电相互作用，这与被认为是18-氨基酸重复序列和微管之间缔合的基础的弱相互作用的分布阵列相反（Butner，K.一、和M. W. Kirschner 115：717-730）。此外，竞争分析表明，R1-R2 IR与微管在微管蛋白位点处结合，该位点与重复序列结合的位点不同。最后，仅对应于R1-R2 IR的10个氨基酸的合成肽足以以序列依赖性方式促进微管蛋白聚合。由于R1-R2 IR在成年tau蛋白中特异性表达，其作用可能是神经元微管组织中观察到的一些发育转变的基础。我们认为R1-R2 IR可能建立了一个成人特异性的、高亲和力的锚，将原本移动的tau分子拴在微管蛋白晶格上，从而增加微管的稳定性。此外，R1-R2 IR表达的情况下，在早期的发展可能允许未成熟的神经元所需的细胞骨架可塑性。
Tau is a developmentally regulated microtubule-associated protein that influences microtubule behavior by directly associating with tubulin. The carboxyl terminus of tau contains multiple 18-amino acid repeats that bind microtubules and are separated by 13-14-amino acid inter- repeat (IR) regions previously thought to function as "linkers." Here, we have performed a high resolution deletion analysis of tau and identified the IR region located between repeats 1 and 2 (the R1-R2 IR) as a unique microtubule binding site with more than twice the binding affinity of any individual repeat. Truncation analyses and site- directed mutagenesis reveal that the binding activity of this site is derived primarily from lys265 and lys272, with a lesser contribution from lys271. These results predict strong, discrete electrostatic interactions between the R1-R2 IR and tubulin, in contrast to the distributed array of weak interactions thought to underlie the association between 18-amino acid repeats and microtubules (Butner, K. A., and M. W. Kirschner. J. Cell Biol. 115:717-730). Moreover, competition assays suggest that the R1-R2 IR associates with microtubules at tubulin site(s) distinct from those bound by the repeats. Finally, a synthetic peptide corresponding to just 10 amino acids of the R1-R2 IR is sufficient to promote tubulin polymerization in a sequence-dependent manner. Since the R1-R2 IR is specifically expressed in adult tau, its action may underlie some of the developmental transitions observed in neuronal microtubule organization. We suggest that the R1-R2 IR may establish an adult- specific, high affinity anchor that tethers the otherwise mobile tau molecule to the tubulin lattice, thereby increasing microtubule stability. Moreover, the absence of R1-R2 IR expression during early development may allow for the cytoskeletal plasticity required of immature neurons.