Expression Studies of Other Unconventional Myosins

我们已经开始分析肌凝蛋白-6的结构和步进模式，这是一种与其他肌凝蛋白在肌动蛋白上运动方向相反的进行性肌凝蛋白。EM研究表明，两个头部之间的角度比大多数肌凝蛋白更容易变化，当与肌动蛋白结合时，马达可以间隔13个肌动蛋白（首选）或11或15个肌动蛋白单体。光学捕获和电子显微镜研究表明，这种分子有时可以采取“尺蠖”式的步骤，即两个头部占据紧密间隔的结合位点。

We have begun to analyze the structure and stepping pattern of myosin-6, a processive myosin which moves in the opposite direction on actin compared to other myosins. EM studies show that the angle between the two heads is more variable than in most myosins and that when bound to actin, the motors can be spaced at 13 actins (preferred) or 11 or 15 actin monomers apart. Optical trapping and EM studies demonstrate that the molecule can sometimes take an "inchworm" like step where the two heads occupy closely spaced binding sites. Myosin 7a is present in the stereocilia of the inner ear and in retinal cells. Mutations of this myosin have been associated with deafness and blindness. We have expressed full length mammalian myosin 7a and find that it is autoinhibited, similiar to what we found with its Drosophila homolog. MyoRip, a myosin 7a binding partner, relieves this autoinhibition and allows for processive movements. We are also exploring whether known myosin 7a interacting partners present in the inner ear interact with the myosin and relieve autoinhibition. In collaboration with John Hammer we have begun to study myosin 19 a mitochondrial associated myosin to complement ongoing cell biological studies.