Microtubule minus end focusing at poles occurs through a centrosome-independent self-organization process that relies on microtubule motors to cross-link and sort microtubules. Our lab has used a cell-free system derived from synchronized cultured cells to show that multiple motor and non-motor proteins cooperatively act to create a microtubule array called mitotic asters, which are steady-state foci of microtubule minus ends at poles. My project aims at characterizing the forces operating at these mitotic asters by using optical traps in collaboration with Blake Charlebois and Alan Hunt (Univ. of Michigan). We biotinylate microtubules in mitotic extracts and then use the optical trap to anchor 0.6 micrometer diameter neutravidin-conjugated silica beads to microtubules at the periphery of the aster array as shown below.
