Myosin A tail domain interacting protein (MTIP) localizes to the inner membrane complex of Plasmodium sporozoites
Myosin A tail domain interacting protein (MTIP) localizes to the inner membrane complex of Plasmodium sporozoites
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DOI：
10.1242/jcs.00194
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发表时间：
2003-01-01
影响因子：
4
通讯作者：
Kappe, SHI
中科院分区：
文献类型：
--
作者：
Bergman, LW;Kaiser, K;Kappe, SHI
顶复合体寄主细胞的侵袭和滑动运动依赖于寄主侵袭期位于质膜下的肌动球蛋白系统。肌球蛋白A （MyoA）是一种十四类非常规肌球蛋白，是运动蛋白。已经提出了一个模型来解释肌动球蛋白马达是如何运作的，但对马达复合物的组成、拓扑结构和连通性知之甚少。利用MyoA颈部和尾部结构域作为诱饵，在酵母双杂交筛选中鉴定出MTIP，这是一种与MyoA相互作用的24kda新蛋白。缺失分析表明，MyoA的15个氨基酸的c末端尾部结构域，而不是颈部结构域，与MTIP特异性相互作用。在疟原虫孢子体中，MTIP定位于内膜复合体（IMC），与MyoA聚集在一起。这些数据支持顶端复合体运动和侵袭的模型，其中MyoA运动蛋白通过其尾部结构域与MTIP相关联，将其固定在外IMC膜上。固定化MyoA的头部结构域移动肌动蛋白丝，这些肌动蛋白丝直接或通过桥接蛋白连接到TRAP家族跨膜蛋白的细胞质结构域。肌动蛋白/TRAP复合体然后由静止的MyoA从zoite的前端重新分布到后端，导致其在底物上向前移动或穿透宿主细胞。
Apicomplexan host cell invasion and gliding motility depend on the parasite's actomyosin system located beneath the plasma membrane of invasive stages. Myosin A (MyoA), a class XIV unconventional myosin, is the motor protein. A model has been proposed to explain how the actomyosin motor operates but little is known about the components, topology and connectivity of the motor complex. Using the MyoA neck and tail domain as bait in a yeast two-hybrid screen we identified MTIP, a novel 24 kDa protein that interacts with MyoA. Deletion analysis shows that the 15 amino-acid C-terminal tail domain of MyoA, rather than the neck domain, specifically interacts with MTIP In Plasmodium sporozoites MTIP localizes to the inner membrane complex (IMC), where it is found clustered with MyoA. The data support a model for apicomplexan motility and invasion in which the MyoA motor protein is associated via its tail domain with MTIP, immobilizing it at the outer IMC membrane. The head domain of the immobilized MyoA moves actin filaments that, directly or via a bridging protein, connect to the cytoplasmic domain of a transmembrane protein of the TRAP family. The actin/TRAP complex is then redistributed by the stationary MyoA from the anterior to the posterior end of the zoite, leading to its forward movement on a substrate or to penetration of a host cell.