Unconventional Myosins of the Hair Cell

描述（由申请人提供）：非常规肌球蛋白包括一类重要的分子运动蛋白。它们在真核生物中参与了无数不同的功能，包括囊泡和mrna的运输，肌动蛋白重组和主要的结构功能。几种肌球蛋白（Ic、VI、VIla和XV）在毛细胞功能中起重要作用。为了确定这些马达在毛细胞中的特定细胞作用，将使用化学遗传学方法（已经在缓慢适应的肌球蛋白-1c中得到验证）。突变的肌球蛋白将被设计成扩大它们的ATP结合袋，这将使它们对合成的ADP类似物敏感。表达这些致敏马达的敲入或转基因小鼠将允许研究每个马达在缓慢适应，肌动蛋白束发育或根尖内吞中的假设作用。这种方法有几个优点；其中最重要的是对肌球蛋白功能的特异性、选择性抑制的严格时间控制。选择性地将特定肌凝蛋白“锁定”到肌动蛋白丝上（rigor复合体）的能力，可以更严格地确定体内功能，而不会产生由过表达引起的伪影。

DESCRIPTION (provided by applicant): Unconventional myosins comprise an important class of molecular motor proteins. They are involved in a myriad of different functions in eukaryotes, including transport of vesicles and mRNAs, actin reorganization, and predominantly structural functions. Several myosins (Ic, VI, VIla, and XV) have essential roles in hair-cell function. To ascertain the specific cellular roles of these respective motors in hair cells, a chemical-genetic approach (already validated for myosin-1c in slow adaptation) will be utilized. Mutant myosins will be engineered to enlarge their ATP binding pockets, which will sensitize them to synthetic ADP analogs. Knock-in or transgenic mice expressing these sensitized motors will allow the study of each motor's hypothesized role(s) in slow adaptation, actin bundle development, or apical endocytosis. This approach provides several advantages; foremost of which is tight temporal control over the specific, selective inhibition of myosin function. The ability to selectively 'lock down' a specific myosin onto actin filaments (rigor complex) enables a more rigorous determination of in vivo function without the artifacts caused by overexpression.