CLASP2 Has Two Distinct TOG Domains That Contribute Differently to Microtubule Dynamics.
CLASP2 Has Two Distinct TOG Domains That Contribute Differently to Microtubule Dynamics.
复制标题
CLASP2 具有两个不同的 TOG 结构域，对微管动力学的贡献不同。
DOI：
10.1016/j.jmb.2015.05.012
复制
发表时间：
2015
影响因子：
5.6
通讯作者：
Hayashi,Ikuko
中科院分区：
文献类型：
--
作者：
Maki,Takahisa;Grimaldi,AshleyD;Fuchigami,Sotaro;Kaverina,Irina;Hayashi,Ikuko
CLIP相关蛋白CLASP是哺乳动物微管（MT）加末端跟踪蛋白（+TIP），在体内促进MT的拯救。它们的正末端定位依赖于其他+TIP、EB 1和CLIP-170，但在细胞的前缘，CLASP显示晶格结合活性。CLASPs的MT相关性被认为受到多个TOG（tumoroverexpressedgene）结构域和富含丝氨酸-精氨酸（SR）的区域的调节，该区域含有EB 1的结合位点。在这里，我们报告的CLASP 2的两个TOG域的晶体结构。这两个结构域由六个HEAT重复序列组成，它们类似于典型的桨状微管蛋白结合TOG结构域，但具有拱形构象。两个TOG结构域之间的曲率的程度和方向是不同的，这意味着它们在MT结合中具有不同的作用。利用生物化学、分子模拟和细胞生物学分析，我们研究了TOG结构域与αβ-微管蛋白之间的相互作用，发现每个结构域与αβ-微管蛋白的结合方式不同。我们的研究结果表明，通过改变域曲率的程度，TOG域可以区分微管蛋白二聚体的结构构象，区分不同状态的MT动态不稳定性，从而发挥差异作为MTs的稳定剂。
CLIP-associated proteins CLASPs are mammalian microtubule (MT) plus-end tracking proteins (+ TIPs) that promote MT rescuein vivo. Their plus-end localization is dependent on other + TIPs, EB1 and CLIP-170, but in the leading edge of the cell, CLASPs display lattice-binding activity. MT association of CLASPs is suggested to be regulated by multiple TOG (tumoroverexpressedgene) domains and by the serine-arginine (SR)-rich region, which contains binding sites for EB1. Here, we report the crystal structures of the two TOG domains of CLASP2. Both domains consist of six HEAT repeats, which are similar to the canonical paddle-like tubulin-binding TOG domains, but have arched conformations. The degrees and directions of curvature are different between the two TOG domains, implying that they have distinct roles in MT binding. Using biochemical, molecular modeling and cell biological analyses, we have investigated the interactions between the TOG domains and αβ-tubulin and found that each domain associates differently with αβ-tubulin. Our findings suggest that, by varying the degrees of domain curvature, the TOG domains may distinguish the structural conformation of the tubulin dimer, discriminate between different states of MT dynamic instability and thereby function differentially as stabilizers of MTs.