GTPγS microtubules mimic the growing microtubule end structure recognized by end-binding proteins (EBs)
GTPγS microtubules mimic the growing microtubule end structure recognized by end-binding proteins (EBs)
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DOI：
10.1073/pnas.1014758108
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发表时间：
2011-03-08
影响因子：
11.1
通讯作者：
Surrey, Thomas
中科院分区：
文献类型：
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作者：
Maurer, Sebastian P.;Bieling, Peter;Surrey, Thomas
微管加末端跟踪蛋白（+TIPs）定位于生长的微管加末端，以调节许多必要的微管功能。末端结合蛋白（EBs）通过识别在生长微管末端的延伸区域中瞬时存在的独特结构特征并通过将其他+ TIPs招募到该区域来形成该网络的核心。允许EB区分该区域中的微管蛋白和远离微管末端的其他潜在微管蛋白结合位点的构象差异的性质是未知的。通过结合体外重建，全内反射荧光显微镜，和电子显微镜，我们在这里证明，一个封闭的微管B晶格与掺入GTP.S，一个缓慢水解的GTP类似物，可以模仿天然EB蛋白结合位点。我们的研究结果表明，鸟嘌呤核苷酸磷酸结合位点是决定EBs与晶格结合微管蛋白亲和力的关键。这定义了EB识别生长微管末端的分子机制。
Microtubule plus-end-tracking proteins (+TIPs) localize to growing microtubule plus ends to regulate a multitude of essential microtubule functions. End-binding proteins (EBs) form the core of this network by recognizing a distinct structural feature transiently existing in an extended region at growing microtubule ends and by recruiting other + TIPs to this region. The nature of the conformational difference allowing EBs to discriminate between tubulins in this region and other potential tubulin binding sites farther away from the microtubule end is unknown. By combining in vitro reconstitution, multicolor total internal reflection fluorescence microscopy, and electron microscopy, we demonstrate here that a closed microtubule B lattice with incorporated GTP.S, a slowly hydrolyzable GTP analog, can mimic the natural EB protein binding site. Our findings indicate that the guanine nucleotide.phosphate binding site is crucial for determining the affinity of EBs for lattice-incorporated tubulin. This defines the molecular mechanism by which EBs recognize growing microtubule ends.