Correlated Waves of Actin Filaments and PIP3 in Dictyostelium Cells
Correlated Waves of Actin Filaments and PIP3 in Dictyostelium Cells
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DOI：
10.1002/cm.20314
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发表时间：
2008-12-01
影响因子：
--
通讯作者：
Uyeda, Taro Q. P.
中科院分区：
文献类型：
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作者：
Asano, Yukako;Nagasaki, Akira;Uyeda, Taro Q. P.
趋化性缺陷的amiB无效突变体网骨细胞显示出两种不同的运动：（1）它们随机延伸突起而没有净位移;（2）它们以角化细胞样的方式持续且单向地迁移。在这里，我们监测了磷脂酰肌醇（3，4，5）-三磷酸（PIP 3）的细胞内分布，以深入了解PIP 3在这些自发运动中的作用。在角质形成细胞样细胞中，PIP 3在基底膜上呈凸状分布，无前部富集。在停滞的细胞中，以及在野生型细胞中，PIP 3在基底膜上重复波浪状变化，包括出现、扩展和消失。当波接近细胞边缘时，诱导板状伪足，并且波的前进速度与角化细胞样细胞的迁移速度相当。PI 3激酶抑制剂LY 294002可抑制停滞细胞中的PIP 3波，并使角质细胞样细胞停止生长。这些结果共同表明，角质细胞样细胞通过将稳定的板状类脂突起耦合到PIP 3波而在PIP 3波上“冲浪”。在野生型或停滞的amiB（-）细胞中同时观察肌动蛋白丝和PIP 3，表明PIP 3波与肌动蛋白丝的波形分布相关。最值得注意的是，PIP 3波通常跟随肌动蛋白波，这表明PIP 3诱导肌动蛋白丝的局部解聚。与这一想法一致，PIP 3的皮质积聚通常与外周的局部收缩相关。我们认为，PIP 3和肌动蛋白丝的波是松散耦合的，并在产生自发细胞极性中发挥重要作用。细胞动力。Cytoskeleton 65：923-934，2008. (C)2008 Wiley-Liss，Inc.
Chemotaxis-deficient amiB-null mutant Dictyostelium cells show two distinct movements: (1) they extend protrusions randomly without net displacements; (2) they migrate persistently and unidirectionally in a keratocyte-like manner. Here, we monitored the intracellular distribution of phosphatidylinositol (3,4,5)-trisphosphate (PIP3) to gain insight into roles PIP3 plays in those spontaneous motilities. In keratocyte-like cells, PIP3 showed convex distribution over the basal membrane, with no anterior enrichment. In stalled cells, as well as in wild type cells, PIP3 repeated wave-like changes, including emergence, expansion and disappearance, on the basal membrane. The waves induced lamellipodia when they approached the cell edge, and the advancing speed of the waves was comparable to the migration speed of the keratocyte-like cells. LY294002, an inhibitor of PI3 kinase, abolished PIP3 waves in stalled cells and stopped keratocyte-like cells. These results together suggested that keratocyte-like cells are "surfing" on the PIP3 waves by coupling steady lamellipodial protrusions to the PIP3 waves. Simultaneous live observation of actin filaments and PIP3 in wild type or stalled amiB(-)cells indicated that the PIP3 waves were correlated with wave-like distributions of actin filaments. Most notably, PIP3 waves often followed actin waves, suggesting that PIP3 induces local depolymerization of actin filaments. Consistent with this idea, cortical accumulation of PIP3 was often correlated with local retraction of the periphery. We propose that the waves of PIP3 and actin filaments are loosely coupled with each other and play important roles in generating spontaneous Cell polarity. Cell Motil. Cytoskeleton 65: 923-934, 2008. (C) 2008 Wiley-Liss, Inc.