Force-Induced Bidirectional Stepping of Cytoplasmic Dynein

摘要: Cytoplasmic dynein is a minus-end-directed microtubule motor whose mechanism of movement remains poorly understood. Here, we use optical tweezers to examine the force-dependent stepping behavior yeast cytoplasmic dynein. We find that primarily advances in 8 nm increments but takes other sized steps (4–24 nm) as well. An opposing force induces more frequent backward by dynein, and walks toward plus end at loads above its stall 7 pN. Remarkably, absence ATP, processively along microtubules under an external load, with less required for minus-end- than plus-end-directed movement. This nucleotide-independent walking reveals alone can drive repetitive detachment-attachment cycles dynein's domains. These results suggest model how two domains coordinate their activities during normal processive motility provide new clues understanding dynein-based living cells.