神经元应对过度活化纤毛驱动蛋白的机理研究

依赖于微管的分子马达OSM-3/KIF17是驱动蛋白2家族蛋白，参与并介导线虫感觉纤毛的构建和维持。体外实验表明，OSM-3-G444E的突变能够使其转换为持续性活化形式的分子马达。然而在体内，该突变则导致了与OSM-3蛋白缺失突变体完全相同的表型。我们初步的研究发现，线虫神经细胞内过度活化的OSM-3-G444E分子马达被限制在了胞体和纤毛以外的区域；双色荧光显微成像的结果显示，过度活化的分子马达与胶质细胞有共定位，提示OSM-3-G444E可能被排出神经元，而后通过内吞进入胶质细胞。利用正向遗传学筛选，申请人得到了OSM-3-G444E分子马达恢复定位在胞体和纤毛内的突变体。申请人将通过全基因组测序结合生物信息学分析的方法，克隆突变体基因，并利用超分辨荧光显微成像、电镜、蛋白质生化和测序平台阐明神经元应对过度活化纤毛驱动蛋白的机理。

OSM-3 is a kinesin II family member that builds cilia in sensory neurons of Caenorhabditis elegans. An OSM-3(G444E) point mutation was previously shown to convert this kinesin constitutively active in vitro. However, the G444E mutation produces a null-mutant like phenotype in vivo. We surprisingly found that the OSM-3(G444E) motor proteins are discarded from sensory neurons into their surrounding gilia cells. Our forward genetic screens have uncovered many mutations that restored the localization and motility of OSM-3(G444E) in sensory cilia. We are cloning these mutations and hope to illuminate the molecular regulation of hyperactive motor protein in the nervous system.