Endocytic vesicles move at the tips of actin tails in cultured mast cells
Endocytic vesicles move at the tips of actin tails in cultured mast cells
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DOI：
10.1038/9048
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发表时间：
1999-05-01
影响因子：
21.3
通讯作者：
Almers, W
中科院分区：
文献类型：
--
作者：
Merrifield, CJ;Moss, SE;Almers, W
* Department of Physiology, University College London, Gower Street, London WC1E 6BT, UK‡ Department of Pathology, Centre Medical Universitaire, Rue Michel-Servet 1, CH-1211Geneva, Switzerland § Max Planck Institute für Medizinische Forschung, Jahnstrasse 29, 69120 Heidelberg, German† 目前地址：Vollum Institute, 3181 Sam Jackson Park Road, Portland,俄勒冈州 97201-3098，美国¶ 电子邮件：almersw@ohsu。人们认为教育素聚合通过驱动片状伪足1的传播来为爬行细胞提供动力。当膜皱褶在巨胞饮过程中吞没外部液体时，也可能涉及到这种情况2。在这里，我们发现，在用由绿色荧光蛋白（GFP）和β-肌动蛋白组成的融合蛋白转染的细胞中，当脂质体（用于吸收液体的囊泡）从质膜上被夹断时，它们会引发肌动蛋白聚合的爆发。然后，脂质体在短暂的肌动蛋白“彗尾”尖端进入胞质溶胶，类似于推动李斯特菌 3 和其他微生物 4、5 穿过受感染细胞的细胞质。与李斯特菌一样，脂质体似乎携带推进肌动蛋白聚合所需的机制。松体运动的方向表明它们可能从膜皱褶的波峰获得这种机制。我们认为肌动蛋白聚合会移动荷叶边的前缘。内吞囊泡也可能利用肌动蛋白聚合从质膜上夹断后进入细胞质。我们用 GFP 标记的 β-肌动蛋白 6 转染大鼠嗜碱性白血病 (RBL) 细胞，并让它们在轻度高渗介质中皱起并进行巨胞饮作用 7。褶皱因 GFP-肌动蛋白吞噬液体而发出微弱的光芒，并在质膜附近形成囊泡结构（未显示）。当这些结构引发肌动蛋白聚合爆发时，它们会发出荧光（图 1a，箭头），导致肌动蛋白条纹穿过细胞，就像肌动蛋白“彗星尾巴”一样。肌动蛋白尾部的尖端呈杯状，似乎是为了容纳囊泡，并且似乎会推动可见的黑色阴影的球形物体。大尾巴有时看起来是空心的（未显示）。
* Department of Physiology, University College London, Gower Street, London WC1E 6BT, UK‡ Department of Pathology, Centre Medical Universitaire, Rue Michel-Servet 1, CH-1211 Geneva, Switzerland § Max Planck Institute für Medizinische Forschung, Jahnstrasse 29, 69120 Heidelberg, Germany† Present address: Vollum Institute, 3181 Sam Jackson Park Road, Portland, Oregon 97201-3098, USA¶ e-mail: almersw@ ohsu. edu ctin polymerization is thought to provide the motive force for crawling cells by driving the spread of lamellipodia1. It may also be involved when membrane ruffles engulf external fluid during macropinocytosis2. Here we show that, in cells transfected with a fusion protein consisting of green fluorescent protein (GFP) and β-actin, pinosomes (vesicles used for fluid uptake) ignite a burst of actin polymerization when they are pinched off from the plasma membrane. Pinosomes then move into the cytosol at the tips of short-lived actin ‘comet tails’ that are similar to those that propel Listeria3 and other microorganisms4, 5 through infected cells. Like Listeria, pinosomes appear to carry the machinery required for propulsive actin polymerization. The direction of pinosome movement indicates that they may acquire this machinery from the crests of membrane ruffles. We suggest that actin polymerization moves the leading edge of ruffles. Endocytic vesicles may also use actin polymerization to move into the cytosol after being pinched off from the plasma membrane.We transfected rat basophilic leukaemia (RBL) cells with GFP-labelled β-actin6 and allowed them to ruffle and undergo macropinocytosis in a mildly hyperosmolar medium7. Ruffles faintly aglow with GFP–actin engulfed fluid and formed vesicular structures near the plasma membrane (not shown). The structures fluoresced (Fig. 1a, arrowhead) as they ignited a burst of actin polymerization that caused a streak of actin to move through the cell, much like actin ‘comet tails’. The tips of the actin tails were cup-shaped as if to accommodate vesicles, and appeared to push spherical objects that were visible as dark shadows. Large tails sometimes appeared hollow (not shown).