Project Summary My long-term goal is to conduct a research program that examines the molecular basis of cellular organization. I have received postdoctoral training in the lab of Dr. John Cooper at Washington University, where I have studied the microtubule motor dynein. All eukaryotes employ microtubule motors such as dynein to organize the intracellular environment in coordination with changes in cell structure and morphology. These scenarios include partitioning the genome during cell division, intracellular transport of proteins and organelles, and perhaps all forms of cell migration. Despite the central role for micortubule motors in these processes, how motors interact with the microtubule substrate in order to produce force is poorly understood. With the research outlined in this proposal, I will develop novel in vivo and in vitro systems to examine how structural features on the microtubule influence motor activity. The development of these tools will be critical for the independent research program that I plan to pursue in my own lab. The broad objective of this proposal is to test the hypothesis that the negatively-charged E-hook motif on the a-tubulin subunit contributes to microtubule function by promoting the binding and/or motility of microtubule motors, and determine whether the role of this motif differs for evolutionarily distinct classes of motors. I will particularly focus on the dynein motor, and seek to identify the molecular basis and consequences of dynein's interaction with the E-hook motif. This project will address these issues by pursuing two aims: Aim 1. Does the tubulin E-hook promote the activity of microtubule motors in vivo? Aim 2. Direct analysis of dynein motility in the presence of the E-hook mutations. Together these analyses will improve our understanding of microtubule function, and may proove useful for the treatment of human disease. Microtubule motors are involved in many diseases, including neuronal pathologies and tumorigenesis; therefore, understanding the molecular details of motor-microtubule interactions may lead to therapies aimed at altering cellular function by modulating the activity of specific motors.