Wade R H, Hyman A A
Institut de Biologie Structurale, 41 Avenue des Martyrs, 38027 Grenoble Cedex1, France.
Curr Opin Cell Biol. 1997 Feb;9(1):12-7. doi: 10.1016/s0955-0674(97)80146-9.
The study of microtubules always manages to surprise and fascinate us, and it has done so yet again over the past year as significant progress has been made in the areas of microtubule nucleation, growth and structural polarity. Microtubule nucleation has been the subject of publications that show the involvement of gamma-tubulin-containing complexes as nucleating templates in the microtubule-organizing centre. It is unclear how this nucleation is compatible with microtubule growth, which appears to take place by an unusual, and perhaps unique, process involving sheet-like extensions that continuously close into tubes as growth proceeds. The related, and longstanding, problem is that of the relationship between tubulin dimer structure and microtubule polarity. This problem appears to be solved. A number of approaches have converged to suggest that the tubulin dimer is organized with beta-tubulin pointing towards the microtubule fast-growing plus end and with alpha-tubulin towards the minus end. Specific decoration with kinesin monomers shows that all microtubules examined to date are basically organized as B-lattices.
对微管的研究总能让我们感到惊喜和着迷，在过去一年里，它再次做到了这一点，因为在微管成核、生长和结构极性方面取得了重大进展。微管成核一直是出版物的主题，这些出版物表明含γ-微管蛋白的复合物作为成核模板参与微管组织中心。目前尚不清楚这种成核如何与微管生长兼容，微管生长似乎通过一个不寻常的、也许是独特的过程发生，该过程涉及片状延伸，随着生长的进行，这些延伸会不断闭合形成管子。相关的、长期存在的问题是微管蛋白二聚体结构与微管极性之间的关系。这个问题似乎已经解决。多种方法都表明，微管蛋白二聚体的组织方式是β-微管蛋白指向微管快速生长的正端，而α-微管蛋白指向负端。用驱动蛋白单体进行的特异性标记表明，迄今为止所检测的所有微管基本上都组织为B晶格。
