Actin cable dynamics in budding yeast
Actin cable dynamics in budding yeast
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DOI：
10.1073/pnas.022462899
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发表时间：
2002-01-22
影响因子：
11.1
通讯作者：
Pon, LA
中科院分区：
文献类型：
--
作者：
Yang, HC;Pon, LA
肌动蛋白索，即沿着芽殖酵母长轴排列的肌动蛋白丝束，对于细胞极性的建立至关重要。我们将绿色荧光蛋白（GFP）融合到肌动蛋白结合蛋白140（Abp 140 p）中，并在活酵母中观察肌动蛋白电缆动力学。我们检测到两个群体的肌动蛋白电缆：（1）芽相关的电缆，从芽沿着母芽轴延伸，和（h）随机取向的电缆，这是相对较短的。Abpl 40 p-GFP的延时成像显示芽相关肌动蛋白缆的长度明显增加。对芽相关线缆上Abpl 40 p-GFP基准标记的移动和光漂白实验中的荧光损失的分析揭示，这种明显的伸长是通过在芽内线缆末端组装新材料以及线缆的相对端朝向芽远端的母细胞尖端移动而发生的。延长肌动蛋白电缆的尖端的延伸率为0.29 - 0.08 μ m/s。Latrunculin A（Lat-A）治疗完全阻断了这一过程。我们还观察到随机取向的电缆在细胞皮层周围以0.59 +/- 0.14 mum/s的速率移动。Lat-A轻度处理不影响随机定向电缆的运动速度。然而，Lat-A处理确实增加了每个细胞随机取向的能动电缆的数量。我们的观察结果表明，在细胞周期过程中建立芽相关的肌动蛋白电缆是通过重新排列现有的电缆，但通过组装新的电缆内的芽或芽颈，然后伸长。
Actin cables, bundles of actin filaments that align along the long axis of budding yeast, are crucial for establishment of cell polarity. We fused green fluorescent protein (GFP) to actin binding protein 140 (Abp140p) and visualized actin cable dynamics in living yeast. We detected two populations of actin cables: (1) bud-associated cables, which extend from the bud along the mother-bud axis, and (h) randomly oriented cables, which are relatively short. Time-lapse imaging of Abpl40p-GFP revealed an apparent increase in the length of bud-associated actin cables. Analysis of movement of Abpl40p-GFP fiduciary marks on bud-associated cables and fluorescence loss in photobleaching experiments revealed that this apparent elongation occurs by assembly of new material at the end of the cable within the bud and movement of the opposite end of the cable toward the tip of the mother cell distal to the bud. The rate of extension of the tip of an elongating actin cable is 0.29 0.08 mum/s. Latrunculin A (Lat-A) treatment completely blocked this process. We also observed movement of randomly oriented cables around the cortex of cells at a rate of 0.59 +/- 0.14 mum/s. Mild treatment with Lat-A did not affect the velocity of movement of randomly oriented cables. However, Lat-A treatment did increase the number of randomly oriented, motile cables per cell. Our observations suggest that establishment of bud-associated actin cables during the cell cycle is accomplished not by realignment of existing cables but by assembly of new cables within the bud or bud neck, followed by elongation.