ABSTRACT
This chapter reviews the data and those from complementary techniques, focusing on their implications for dynein action and regulation. Electron microscopy (EM) has provided insights into the mechanism of dynein at a variety of scales, from individual subdomains of the force-generating heavy chain, to microtubule- and regulator-bound assemblies. Fundamentally, dynein movement arises from angstrom-scale changes associated with the binding and hydrolysis of adenosine triphosphate in its active site. One technique that has been successful in bridging the spatial scales is EM. Historically, EM provided views of axonemal sections treated with contrast-enhancing stains, which were instrumental in the discovery of dynein in the 1960s. The chapter highlights three scales at which EM and complementary techniques have provided significant insights: first, individual dynein heavy chains and their constituent subdomains; second, dynein dimers bound to and stepping along microtubules; third, assemblies of dynein and regulatory co-factors.
