INTACT ALPHA-ACTININ MOLECULES ARE NEEDED FOR BOTH THE ASSEMBLY OF ACTIN INTO THE TAILS AND THE LOCOMOTION OF LISTERIA-MONOCYTOGENES INSIDE INFECTED-CELLS
INTACT ALPHA-ACTININ MOLECULES ARE NEEDED FOR BOTH THE ASSEMBLY OF ACTIN INTO THE TAILS AND THE LOCOMOTION OF LISTERIA-MONOCYTOGENES INSIDE INFECTED-CELLS
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DOI：
10.1002/cm.970280202
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发表时间：
1994-01-01
影响因子：
--
通讯作者：
SANGER, JW
中科院分区：
文献类型：
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作者：
DOLD, FG;SANGER, JM;SANGER, JW
在感染性细菌单核细胞增生李斯特菌被宿主细胞吞噬后，它离开溶酶体并募集宿主细胞的细胞骨架蛋白以组装主要由与α-辅肌动蛋白交联的肌动蛋白丝组成的固定尾部。在细菌和尾巴之间的界面上不断补充收缩蛋白质，伴随着细菌在伸长的尾巴前面的推进。当细菌接触宿主细胞膜时，它将膜推出成波浪形的管状结构或丝状伪足，丝状伪足在其后面的细胞骨架蛋白的尾部包裹细菌的尖端。先前的工作已经证明，α-辅肌动蛋白可以被切割成两个蛋白水解片段，其显微注射到细胞中干扰应力纤维的完整性。将53 kD α-辅肌动蛋白片段显微注射到单核细胞增生李斯特菌感染的细胞中，诱导细菌尾部的丢失并导致细菌变得静止。当注射53 kD片段时，具有丝状伪足的感染细胞失去其丝状伪足。这些结果表明，完整的α-辅肌动蛋白分子在李斯特菌的细胞内运动中起着重要作用，可能是通过稳定细菌向前移动所需的固定尾部中的肌动蛋白纤维。当将粘着斑蛋白注射到受感染的细胞中时，粘着斑蛋白与尾部相关。塔林抗体染色表明，这种蛋白质，也存在于尾巴。这些观察结果表明，尾巴共享的属性通常存在于宿主细胞中的附着斑块。这个模型可以解释细菌（1）在细胞质内移动和（2）挤出细胞表面形成丝状伪足的能力。附着斑蛋白，α-辅肌动蛋白，talin和黏着斑蛋白，可以结合和稳定肌动蛋白丝，因为它们在细菌后面伸展，另外还可以使尾部结合到丝状伪足中的细胞膜上。(C)1994 Wiley-Liss，Inc.
After the infectious bacterium, Listeria monocytogenes, is phagocytosed by a host cell, it leaves the lysosome and recruits the host cell's cytoskeletal proteins to assemble a stationary tail composed primarily of actin filaments cross-linked with alpha-actinin. The continual recruitment of contractile proteins to the interface between the bacterium and the tail accompanies the propulsion of the bacterium ahead of the elongating tail. When a bacterium contacts the host cell membrane, it pushes out the membrane into an undulating tubular structure or filopodium that envelops the bacterium at the tip with the tail of cytoskeletal proteins behind it. Previous work has demonstrated that alpha-actinin can be cleaved into two proteolytic fragments whose microinjection into cells interferes with stress fiber integrity. Microinjection of the 53 kD alpha-actinin fragment into cells infected with Listeria monocytogenes, induces the loss of tails from bacteria and causes the bacteria to become stationary. Infected cells that possess filopodia when injected with the 53 kD fragment lose their filopodia. These results indicate that intact alpha-actinin molecules play an important role in the intracellular motility of Listeria, presumably by stabilizing the actin fibers in the stationary tails that are required for the bacteria to move forward. Fluorescently labeled vinculin associated with the tails when it was injected into infected cells. Talin antibody staining indicated that this protein, also, is present in the tails. These observations suggest that the tails share properties of attachment plaques normally present in the host cells. This model would explain the ability of the bacterium (1) to move within the cytoplasm and (2) to push out the surface of the cell to form a filopodium. The attachment plaque proteins, alpha-actinin, talin, and vinculin, may bind and stabilize the actin filaments as they polymerize behind the bacteria and additionally could also enable the tails to bind to the cell membrane in the filopodia. (C) 1994 Wiley-Liss, Inc.