Reduction in microtubule dynamics in vitro by brain microtubule-associated proteins and by a microtubule-associated protein-2 second repeated sequence analogue.
Reduction in microtubule dynamics in vitro by brain microtubule-associated proteins and by a microtubule-associated protein-2 second repeated sequence analogue.
复制标题
脑微管相关蛋白和微管相关蛋白-2第二重复序列类似物在体外减少微管动力学。
DOI：
10.1111/j.1471-4159.1993.tb03225.x
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发表时间：
1993
影响因子：
4.7
通讯作者：
Purich,DL
中科院分区：
文献类型：
--
作者：
Yamauchi,PS;Flynn,GC;Marsh,RL;Purich,DL
微管相关蛋白（MAP）与组装的微管（MT）的结合可以通过添加聚谷氨酸盐来减少，而不会显著的MT解聚或干扰MT延伸反应。MAP耗尽的MT中随后的聚合物长度重新分布发生在无MAP MT所观察到的时间尺度特征上。即使在没有机械剪切的情况下也会发生再分布阶段，并且没有端对端退火的明显影响，如聚合物长度和MT数浓度增量变化的时间过程所示。我们还观察到当[MAP]/[微管蛋白]比值降低时，MT长度再分布的速率更高。总之，这些结果表明，MT长度再分布率的MAP含量的影响很大，数据是兼容的动态不稳定性模型。我们还发现，与MAP-2的MT结合区中的第二重复序列对应的肽类似物也可以显著延迟MT长度再分布动力学，这一发现与该肽在没有MAP的情况下促进微管蛋白聚合并从MT中取代MAP-2的能力一致。这些结果进一步证明MAP可以调节MT组装/分解动力学，并且肽类似物可以模拟完整MAP的作用，而无需MT结合区域中的三个连续重复序列。
Microtubule‐associated protein (MAP) binding to assembled microtubules (MTs) can be reduced by the addition of polyglutamate without significant MT depolymerization or interference with MT elongation reactions. Ensuing polymer length redistribution in MAP‐depleted MTs occurs on a time scale characteristic of that observed with MAP‐free MTs. The redistribution phase occurs even in the absence of mechanical shearing and without appreciable effects from end‐to‐end annealing, as indicated by the time course of incremental changes in polymer length and MT number concentration. We also observed higher rates of MT length redistribution when the [MAP]/[tubulin] ratio was decreased. Together, these results demonstrate that MT length redistribution rates are greatly influenced by MAP content, and the data are compatible with the dynamic instability model. We also found that a peptide analogue corresponding to the second repeated sequence in the MT‐binding region of MAP‐2 can also markedly retard MT length redistribution kinetics, a finding that accords with the ability of this peptide to promote tubulin polymerization in the absence of MAPs and to displace MAP‐2 from MTs. These results provide further evidence that MAPs can modulate MT assembly/disassembly dynamics and that peptide analogues can mimic the action of intact MAPs without the need for three contiguous repeated sequences in the MT‐binding region.