XMAP FROM XENOPUS EGGS PROMOTES RAPID PLUS END ASSEMBLY OF MICROTUBULES AND RAPID MICROTUBULE POLYMER TURNOVER
XMAP FROM XENOPUS EGGS PROMOTES RAPID PLUS END ASSEMBLY OF MICROTUBULES AND RAPID MICROTUBULE POLYMER TURNOVER
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DOI：
10.1083/jcb.127.4.985
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发表时间：
1994-11-01
影响因子：
7.8
通讯作者：
CASSIMERIS, L
中科院分区：
文献类型：
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作者：
VASQUEZ, RJ;GARD, DL;CASSIMERIS, L
我们使用视频增强DIC显微镜检查XMAP的作用，XMAP是一种来自爪蟾卵的M(r) 215,000微管相关蛋白（Gard， D. L.和M. W. Kirschner, 1987）。[j] .细胞工程学报，2011,(5):522 - 522。我们的研究结果表明，XMAP实质上改变了微管在正端组装的参数。具体来说，添加0.2 μ M XMAP导致(a)伸长速度增加7-10倍，(b)缩短速度增加约3倍，(c)几乎消除了挽救（从快速缩短到伸长的转换）。因此，添加XMAP导致轴突染色体正端组装更长的，但更动态的微管，这些微管在突变后被分解回轴突染色体成核位点。与先前的观察一致（Gard， D. L.和M. W. Kirschner. 1987）。J. Cell Biol. 105:2203-2215)， XMAP对负端的影响要小得多，伸长速度仅增加1.5-3倍。这些结果表明，与脑map不同，XMAP促进了聚合物的组装和转换，并表明XMAP与微管蛋白的相互作用以及XMAP在体内的功能可能不同于之前所描述的map。
We have used video-enhanced DIC microscopy to examine the effects of XMAP, a M(r) 215,000 microtubule-associated protein from Xenopus eggs (Gard, D. L., and M. W. Kirschner. 1987. J. Cell Biol. 105:2203-2215), on the dynamic instability of microtubules nucleated from axoneme fragments in vitro. Our results indicate that XMAP substantially alters the parameters of microtubule assembly at plus ends. Specifically, addition of 0.2 mu M XMAP resulted in (a) 7-10-fold increase in elongation velocity, (b) approximately threefold increase in shortening velocity, and (c) near elimination of rescue (the switch from rapid shortening to elongation). Thus, addition of XMAP resulted in the assembly of longer, but more dynamic, microtubules from the plus ends of axonemes which upon catastrophe disassembled back to the axoneme nucleation site. In agreement with previous observations (Gard, D. L., and M. W. Kirschner. 1987. J. Cell Biol. 105:2203-2215), the effects of XMAP on the minus end were much less dramatic, with only a 1.5-3-fold increase in elongation velocity. These results indicate that XMAP, unlike brain MAPs, promotes both polymer assembly and turnover, and suggests that the interaction of XMAP with tubulin and the function of XMAP in vivo may differ from previously characterized MAPs.