Motility of ActA protein-coated microspheres driven by actin polymerization
Motility of ActA protein-coated microspheres driven by actin polymerization
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DOI：
10.1073/pnas.96.9.4908
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发表时间：
1999-04-27
影响因子：
11.1
通讯作者：
Theriot, JA
中科院分区：
文献类型：
--
作者：
Cameron, LA;Footer, MJ;Theriot, JA
肌动蛋白聚合是在板足和丝足的前缘以及单核增生李斯特菌等细胞内可运动的细菌病原体表面产生运动力所必需的，肌动蛋白丝聚合的局部催化是在L中完成的，单核增生细菌蛋白ActA，在富含肌动蛋白的细胞质提取物中包被纯化ActA蛋白的聚苯乙烯珠可以进行定向运动。因此，ActA产生的基于肌动蛋白聚合的运动性可以用于移动非生物货物，正如经典运动分子（如运动蛋白和肌球蛋白）所证明的那样。对称包覆颗粒的单向运动的启动是珠粒大小和表面蛋白质密度的函数。当肌动蛋白丝密度的随机波动或热运动导致局部不对称时，小珠子（直径小于或等于0.5 μ m）启动了基于肌动蛋白的运动，这表明动态肌动蛋白细胞骨架具有自发自组织成能够产生单向力的极性结构的固有能力。较大的微珠（直径达2 μ m）只有在一个半球上涂覆微珠时才会引起表面不对称，这就解释了为什么相对较大的L，单核细胞增生细胞需要在其表面上的ActA极性分布才能移动。
Actin polymerization is required for the generation of motile force at the leading edge of both lamellipodia and filopodia and also at the surface of motile intracellular bacterial pathogens such as Listeria monocytogenes, Local catalysis of actin filament polymerization is accomplished in L, monocytogenes by the bacterial protein ActA, Polystyrene beads coated with purified ActA protein can undergo directional movement in an actin-rich cytoplasmic extract. Thus, the actin polymerization based motility generated by ActA can be used to move nonbiological cargo, as has been demonstrated for classical motor molecules such as kinesin and myosin, Initiation of unidirectional movement of a symmetrically coated particle is a function of bead size and surface protein density. Small beads (less than or equal to 0.5 mu m in diameter) initiate actin-based motility when local asymmetries are built up by random fluctuations of actin filament density or by thermal motion, demonstrating the inherent ability of the dynamic actin cytoskeleton to spontaneously self-organize into a polar structure capable of generating unidirectional force. Larger beads (up to 2 mu m in diameter) can initiate movement only if surface asymmetry is introduced by coating the beads on one hemisphere, This explains why the relatively large L, monocytogenes requires polar distribution of ActA on its surface to move.