Connolly J A, Oldfin B V
Eur J Cell Biol. 1985 Nov;39(1):173-8.
We have used the microtubule-stabilizing drug taxol to examine the relationship between microtubules and the appearance and cell surface distribution of acetylcholine receptors (AChRs) in primary cultures of chick embryonic muscle cells. Taxol at a 5-microM concentration induced the large scale polymerization of tubulin in muscle cells that was most obvious as intermittent bundles of microtubules along the myotube. Prominent bundles of microtubules were also clearly visible in the fibroblasts. This concentration of taxol had no significant effect on the incorporation rate, increased synthesis induced by brain extract or the total cell surface number of AChRs measured over a 24-h period. Thus, excess polymerization of microtubules does not affect the movement of receptors to the cell surface. However, when cell surface AChR distribution was examined using rhodamine-conjugated alpha-bungarotoxin, taxol treatment of myotubes was shown to induce the aggregation of receptors. If receptors were labeled before taxol addition, aggregation of these prelabeled receptors was also seen, a result indicating that taxol can induce the movement of receptors already in the membrane. We believe this evidence further implicates microtubules as being involved in the movement of these cell surface receptors in the plane of the myotube membrane.
我们使用微管稳定药物紫杉醇来研究微管与鸡胚肌细胞原代培养物中乙酰胆碱受体（AChRs）的出现及细胞表面分布之间的关系。5微摩尔浓度的紫杉醇诱导肌细胞中微管蛋白大规模聚合，最明显的表现为沿肌管形成断断续续的微管束。在成纤维细胞中也能清楚地看到明显的微管束。该浓度的紫杉醇对掺入率、脑提取物诱导的合成增加或24小时内测量的AChRs总细胞表面数量均无显著影响。因此，微管的过度聚合不会影响受体向细胞表面的移动。然而，当使用罗丹明偶联的α-银环蛇毒素检测细胞表面AChR分布时，紫杉醇处理的肌管显示出诱导受体聚集。如果在添加紫杉醇之前标记受体，也会观察到这些预先标记的受体发生聚集，这一结果表明紫杉醇可以诱导已经在膜中的受体移动。我们认为这一证据进一步表明微管参与了这些细胞表面受体在肌管膜平面内的移动。
