Stephen J. King
Associate Professor, MBB
Ph.D. University of Colorado-Boulder
Office: 213 BSB
Phone: (816) 235-6290
E-mail: KingSJ
Research Areas
Molecular motors and motility, cytoskeleton, protein : protein interactions
Current Interests
"Cytoplasmic dynein is a large multisubunit motor that converts chemical energy in ATP into mechanical force, moving cargo toward the minus-end of microtubules found at the cell center. Dynactin, another multisubunit complex, has multiple structural features that allow it to bind simultaneously to cytoplasmic dynein, microtubules, and cargo. Together, cytoplasmic dynein and dynactin are absolutely required for critical cellular processes such as nuclear migration and orientation, centrosome/mitotic spindle assembly and function, neuronal transport, and vesicular organelle trafficking and distribution. I am using a combination of microscopic, biochemical, and genetic approaches to determine the mechanism by which dynein and dynactin are able to provide motile force for so many cellular processes. Microscopic examinations of dynein-coated cargo in the absence of dynactin show that dynein ""walks"" along microtubules short distances before diffusing away. The addition of dynactin to the cargo provides an extra weak-affinity microtubule binding site that diminishes the probability of cargo diffusing away from the microtubule during dynein-based movement. In this way, dynactin allows cytoplasmic dynein to take more steps per encounter with a microtubule. Future analysis of the cytoplasmic dynein/dynactin motility mechanism should eventually lead to the identification of upstream regulatory factors governing activity, and to the determination of how activity is spatially targeted and temporally regulated within the cell."
Research Support
This work is supported by the National Institutes of Health and the American Heart Association.
