The dynein family is a group of minus-end directed microtubule motor proteins vital for long- range cytoplasmic cargo transport and ciliary beating. The dynein heavy chain consists of an N- terminal tail domain responsible for cargo binding and dimerization, and a C-terminal motor domain. In order to move, the dynein motor cyclically binds and releases from the microtubule by changing the conformation of its microtubule-binding domain (MTBD). In chapter 3, I solve the structure of cytoplasmic and axonemal dynein MTBDs bound to microtubules by cryo-EM. From this, I present a new model of how dynein interacts with the microtubule, and a novel role of axonemal dyneins in physically distorting the microtubule. In my chapter 4, I use cryo- electron microscopy to demonstrate why dynein moves towards the minus-end and not the plus-end of microtubules. To do this, I image the structural difference between wild-type dynein and an engineered dynein that walks in reverse. Along with the work of collaborators, these results demonstrate that movement of a flexible element within the dynein motor domain called the linker is the key determinant of dynein directionality. In chapter 5, I investigate how herpes viruses hijack dynein. During cell entry, these viruses are transported by dynein over long distances from the cell periphery to the nucleus. The basis of the interaction between dynein and herpes is unknown. I use a combination of cell biology and mass-spectrometry to identify host proteins that are potentially recruited to the virus and in turn recruit dynein.