REGULATION OF DICTYOSTELIUM MYOSIN BY PHOSPHORYLATION

分子马达肌球蛋白与肌动蛋白驱动肌肉的相互作用 收缩和细胞形状和运动的各种变化 非肌肉真核细胞生物学的基础。对经济发展至关重要 肌球蛋白在非肌肉细胞中的功能是对其组装的调节 变成细丝和更高阶的结构，例如收缩环， 其组装在空间和时间上是受控制的。小才是 已知这种时空控制的分子基础，但 肌球蛋白分子的磷酸化似乎起到了关键作用。灯 链磷酸化可能调节肌球蛋白细丝的组装 但可能主要控制肌球蛋白的运动功能。重的 链磷酸化可能主要参与肌球蛋白的调节 细丝组件。这项建议的具体目的是研究 Dictyostelials中的肌球蛋白磷酸化，这种有机体允许 生化、分子遗传学和生理学的融合 接近了。因此，它提供了一个独特的机会来调查 细胞如何运动、分裂和改变形状的分子基础 细胞和发育信号。下一步的实验计划 五年期间可分为三个部分： 1.激酶的生化、结构和分子遗传学研究 和负责控制网柄菌属的磷酸酶 肌球蛋白的磷酸化。 2.对这些影响的生化和结构研究 磷酸化对纯化肌球蛋白功能的影响。 3.体内磷酸化效应的表征 肌球蛋白的行为和功能。 后者是由于最近复杂的 分子遗传学技术 网柄网柄菌属。

Interaction of the molecular motor myosin with actin drives muscle contraction and various changes in cell shape and movements that are fundamental to the biology of nonmuscle eukaryotic cells. Essential to the function of myosin in nonmuscle cells is the regulation of its assembly into filaments and higher order structures such as the contractile ring, the assembly of which is spatially and temporally controlled. Little is known about the molecular basis of such spatial and temporal control but phosphorylation of the myosin molecule appears to play a key role. Light chain phosphorylation may regulate myosin filament assembly in some systems, but may primarily control the motor function of myosin. Heavy chain phosphorylation may be primarily involved in regulation of myosin filament assembly. The specific aim of this proposal is to study the roles of myosin phosphorylation in Dictyostelium, an organism that allows the convergence of biochemical, molecular genetic, and physiological approaches. It therefore offers a unique opportunity to investigate the molecular basis of how a cell moves, divides, and changes shape in response to cellular and developmental signals. The experimental plan for the next five year period can be divided into three parts: 1. Biochemical, structural, and molecular genetic studies on the kinases and phosphatases that are responsible for the control of Dictyostelium myosin phosphorylations. 2. Biochemical and structural studies on the effects of these phosphorylations on the functions of purified myosin. 3. Characterization of the effects of phosphorylation on the in vivo behavior and function of the myosin. The latter is made possible by recent applications of sophisticated molecular genetic techniques to Dictyostelium.