Naoz Moshe, Manor Uri, Sakaguchi Hirofumi, Kachar Bechara, Gov Nir S
Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel.
Biophys J. 2008 Dec 15;95(12):5706-18. doi: 10.1529/biophysj.108.143453. Epub 2008 Oct 20.
We present a physical model that describes the active localization of actin-regulating proteins inside stereocilia during steady-state conditions. The mechanism of localization is through the interplay of free diffusion and directed motion, which is driven by coupling to the treadmilling actin filaments and to myosin motors that move along the actin filaments. The resulting localization of both the molecular motors and their cargo is calculated, and is found to have an exponential (or steeper) profile. This localization can be at the base (driven by actin retrograde flow and minus-end myosin motors), or at the stereocilia tip (driven by plus-end myosin motors). The localization of proteins that influence the actin depolymerization and polymerization rates allow us to describe the narrow shape of the stereocilia base, and the observed increase of the actin polymerization rate with the stereocilia height.
我们提出了一个物理模型，该模型描述了在稳态条件下肌动蛋白调节蛋白在静纤毛内的主动定位。定位机制是通过自由扩散和定向运动的相互作用，这种相互作用由与肌动蛋白踏车丝以及沿肌动蛋白丝移动的肌球蛋白马达的耦合驱动。计算了分子马达及其货物的最终定位，发现其具有指数（或更陡峭）分布。这种定位可以在基部（由肌动蛋白逆行流和负端肌球蛋白马达驱动），也可以在静纤毛尖端（由正端肌球蛋白马达驱动）。影响肌动蛋白解聚和聚合速率的蛋白质的定位使我们能够描述静纤毛基部的狭窄形状，以及观察到的肌动蛋白聚合速率随静纤毛高度的增加。
