One of the main objectives of the research performed in the Cochran laboratory is to study and understand the details of mechanochemical force transduction in kinesin superfamily motor proteins and elucidate how microtubules stimulate their ATPase activity. Conventional kinesins utilize the chemical energy stored in ATP in order to produce directed force along microtubule filaments. The details of force generation vary greatly among kinesins: the motility of different kinesin subfamilies can be towards either end of the polar microtubule, some subfamilies are processive motors - taking multiple steps along a filament without dissociating, and others are non-processive - requiring multiple heads working in concert in order to achieve motility. Additionally, a growing number of non-motile kinesins have a very different cellular function - the regulation of microtubule dynamics. Coupled to these divergent cellular activities are differences in kinetic ATPase cycles, as well as structural changes in the conserved motor core. These projects seek to investigate the details of kinesin structure and function in order to understand how subtle differences (e.g. amino acid substitutions and variation of loop lengths) affects the kinetic cycles and force generating characteristics of unconventional kinesin family motors.
To achieve this goal, we will study the detailed structure and thermodynamic energy landscape of an unconventional kinesin, kinesin-10/NOD to determine differences between motile and non-motile kinesin mechanochemistry. In addition, we will characterize our engineered biochemical "metal switch" for kinesin and myosin ATPases as well as small G proteins using a novel experimental approach to probe functional metal-enzyme interactions. Finally, we will investigate the high resolution structure of a kinesin motor in complex with tubulin in order to visualize the detailed mechanism by which interaction with microtubules accelerates the kinesin ATP hydrolysis cycle. The knowledge acquired from the proposed research will expand our understanding of kinesin-MT and other protein-MT systems and will provide valuable insights into possible avenues for therapeutic targeting to combat diseases such as Alzheimer's, Parkinson's, and cancer.