PrP可抑制tau介导的体外微管形成作用

Prion protein inhibits tau-mediated microtubule formation

目的研究朊蛋白(PRP)对微管相关蛋白(TAU)介导的体外微管形成的影响。方法我们从兔脑组织中纯化出微管蛋白,并纯化出原核表达的TAU和PRP蛋白。利用电子显微镜技术显示微管蛋白的聚集、TAU对微管蛋白的聚集的影响,及PRP对TAU介导的微管蛋白形成微管的影响。通过GST PULL DOWN实验研究TAU与微管蛋白的相互作用,PRP对TAU与微管蛋白相互作用的影响。结果电子显微镜负染显示纯化的微管蛋白在一定的实验条件下可聚集形成直径为25 NM的微管结构。在反应体系中加入TAU后微管样结构的形成明显增加,而加入PRP后可显著地抑制TAU对微管结构形成的促进作用。重组TAU能与提取的天然微管蛋白在体外结合,而PRP可明显地抑制TAU与微管蛋白的结合作用,并呈现剂量依赖关系。结论 TAU蛋白可促进微管蛋白形成微管结构,而PRP可通过与TAU的相互作用抑制微管的形成。

Objective To study the inhibitive effect of prion protein （PrP） on the formation of microtubules enhanced by microtubule-associated protein tau. Methods Tubulin protein was extracted from rabbit brain. Both recombinant tau protein and PrP protein was expressed and purified from E. coll. Microtubules formed by tubulin were observed by electron microscope （EM）. GST pull down test was used to judge PrP effect on the interaction of tau and tubulin protein. Results The extracted tubulin could assemble microtubules and form complex with tau in vitro. The recombinant tau protein significantly enhanced the formation of microtubules. PrP protein impeded the molecular interaction between tau and tubulin in a dose-dependent manner and inhibited tau-mediated microtubules formation. Conclusion Tau protein facilitated microtubule formation from tubulin, PrP protein inhibited tau-mediated microtubule formation.