Böhm K J, Vater W, Steinmetzer P, Unger E
Institute of Microbiology and Experimental Therapy, Department of Experimental Cell Research, Jena, Germany.
Acta Histochem Suppl. 1991;41:65-72.
Using an ultrathin-sectioning electron microscopic procedure, no efficient binding of coated vesicles to microtubules (both purified from brain tissue) could be achieved, independently of the presence of microtubule-associated proteins. Addition of the ATP analogue AMP-PNP or the inorganic tripolyphosphate, known to cause tight associations of (uncoated) vesicles to microtubules by means of specific motor proteins, could not enhance the binding efficiency. Moreover, crude preparations of clathrin, the major protein of the coat, did not affect the turbidity course of microtubule assembly. These results were confirmed by electrophoresis indicating that within the preparations of microtubule protein, obtained by temperature-dependent cycles of disassembly/reassembly, constituents of coated vesicles were not present. Beside this, coated vesicles have never been found among microtubules reconstituted in vitro. Vice versa, preparations of coated vesicles were completely free of microtubules. Our results suggest that further proteins should be involved in the binding of coated vesicles to microtubules, if there is indeed a biologically relevant interaction.
使用超薄切片电子显微镜技术，无论是否存在微管相关蛋白，都无法实现包被小泡与微管（均从脑组织中纯化得到）的有效结合。添加已知可通过特定驱动蛋白使（未包被的）小泡与微管紧密结合的ATP类似物AMP-PNP或无机三聚磷酸，均无法提高结合效率。此外，包被的主要蛋白网格蛋白的粗制品并不影响微管组装的浊度变化过程。电泳结果证实了这些结果，表明在通过温度依赖性解聚/重组循环获得的微管蛋白制剂中，不存在包被小泡的成分。除此之外，在体外重构的微管中从未发现过包被小泡。反之，包被小泡的制剂中完全没有微管。我们的结果表明，如果确实存在生物学上相关的相互作用，那么可能还有其他蛋白质参与包被小泡与微管的结合。
