Sakato Miho, King Stephen M
Department of Biochemistry, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-3305, USA.
J Struct Biol. 2004 Apr-May;146(1-2):58-71. doi: 10.1016/j.jsb.2003.09.026.
Dyneins are highly complex molecular motors that transport their attached cargo towards the minus end of microtubules. These enzymes are required for many essential motile activities within the cytoplasm and also power eukaryotic cilia and flagella. Each dynein contains one or more heavy chain motor units that consist of an N-terminal stem domain that is involved in cargo attachment, and six AAA+ domains (AAA1-6) plus a C-terminal globular segment that are arranged in a heptameric ring. At least one AAA+ domain (AAA1) is capable of ATP binding and hydrolysis, and the available data suggest that one or more additional domains also may bind nucleotide. The ATP-sensitive microtubule binding site is located at the tip of a 10nm coiled coil stalk that emanates from between AAA4 and AAA5. The function of this motor both in the cytoplasm and the flagellum must be tightly regulated in order to result in useful work. Consequently, dyneins also contain a series of additional components that serve to define the cargo-binding properties of the enzyme and which act as sensors to transmit regulatory inputs to the motor units. Here we describe the two basic dynein designs and detail the various regulatory systems that impinge on this motor within the eukaryotic flagellum.
动力蛋白是高度复杂的分子马达，可将其附着的货物向微管的负端运输。这些酶对于细胞质内许多基本的运动活动是必需的，也是真核生物纤毛和鞭毛的动力来源。每个动力蛋白都包含一个或多个重链运动单元，这些单元由一个参与货物附着的N端茎域、六个AAA+结构域（AAA1 - 6）以及一个排列成七聚体环的C端球状片段组成。至少一个AAA+结构域（AAA1）能够结合并水解ATP，现有数据表明一个或多个其他结构域也可能结合核苷酸。ATP敏感的微管结合位点位于从AAA4和AAA5之间伸出的10纳米卷曲螺旋柄的顶端。为了产生有效的作用，这种马达在细胞质和鞭毛中的功能都必须受到严格调控。因此，动力蛋白还包含一系列额外的组件，这些组件用于定义该酶的货物结合特性，并作为传感器将调节输入传递给运动单元。在这里，我们描述了两种基本的动力蛋白设计，并详细介绍了在真核生物鞭毛中影响这种马达的各种调节系统。
