Expression Studies of Other Unconventional Myosins

我们已经开始分析肌球蛋白6的结构和步进模式，肌球蛋白6是一种进行性肌球蛋白，与其他肌球蛋白相比，它在肌动蛋白上以相反的方向移动。EM研究表明，两个头部之间的角度比大多数肌球蛋白更可变，并且当与肌动蛋白结合时，马达可以间隔13个肌动蛋白（优选）或11或15个肌动蛋白单体。光学捕获和EM研究表明，分子有时可以采取“尺蠖”般的步骤，其中两个头部占据紧密间隔的结合位点。 肌球蛋白7a存在于内耳的静纤毛和视网膜细胞中。 这种肌球蛋白的突变与耳聋和失明有关。 我们已经表达了全长哺乳动物肌球蛋白7a，并发现它是自抑制的，类似于我们在果蝇同源物中发现的。 MyoRip是一种肌球蛋白7a结合伴侣，可以缓解这种自抑制，并允许进行性运动。 我们也正在探索是否已知的肌球蛋白7a相互作用的合作伙伴存在于内耳与肌球蛋白相互作用，并减轻自身抑制。 在与约翰·哈默的合作中，我们已经开始研究肌球蛋白19，一种线粒体相关的肌球蛋白，以补充正在进行的细胞生物学研究。

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.