Dissection of the Ascaris sperm motility machinery identifies key proteins involved in major sperm protein-based amoeboid locomotion
Dissection of the Ascaris sperm motility machinery identifies key proteins involved in major sperm protein-based amoeboid locomotion
复制标题
DOI：
10.1091/mbc.e03-04-0246
复制
发表时间：
2003-12-01
影响因子：
3.3
通讯作者：
Roberts, TM
中科院分区：
文献类型：
--
作者：
Buttery, SM;Ekman, GC;Roberts, TM
尽管蛔虫精子的运动能力与许多其他类型的爬行细胞中所见的运动能力非常相似，但驱动运动的片状足动力学是基于主要精子蛋白（MSP）而不是肌动蛋白的细胞骨架的调节所致。蛔虫精子细胞骨架的动力学可以在无细胞体外系统中进行研究，该系统基于由 MSP 丝束构建的纤维对质膜囊泡的运动。除了 ATP、MSP 和质膜蛋白之外，在这种无细胞提取物中重建 MSP 运动性还需要胞质蛋白来协调产生运动的 MSP 丝的位点特异性组装和捆绑。在这里，我们鉴定了一部分细胞质，它由少量蛋白质组成，但包含组装纤维所需的所有可溶性成分。我们纯化了其中两种蛋白质，命名为 MSP 纤维蛋白 (MFP) 1 和 2，并通过免疫标记证明两者均位于细胞和纤维中的 MSP 细胞骨架中。这些蛋白质在体外对纤维组装有相互影响：MFP1 降低纤维生长速度，而 MFP2 增加生长速度。
Although Ascaris sperm motility closely resembles that seen in many other types of crawling cells, the lamellipodial dynamics that drive movement result from modulation of a cytoskeleton based on the major sperm protein (MSP) rather than actin. The dynamics of the Ascaris sperm cytoskeleton can be studied in a cell-free in vitro system based on the movement of plasma membrane vesicles by fibers constructed from bundles of MSP filaments. In addition to ATP, MSP, and a plasma membrane protein, reconstitution of MSP motility in this cell-free extract requires cytosolic proteins that orchestrate the site-specific assembly and bundling of MSP filaments that generates locomotion. Here, we identify a fraction of cytosol that is comprised of a small number of proteins but contains all of the soluble components required to assemble fibers. We have purified two of these proteins, designated MSP fiber proteins (MFPs) 1 and 2 and demonstrated by immunolabeling that both are located in the MSP cytoskeleton in cells and in fibers. These proteins had reciprocal effects on fiber assembly in vitro: MFP1 decreased the rate of fiber growth, whereas MFP2 increased the growth rate.