Clustering of cortical dynein regulates the mechanics of spindle orientation in human mitotic cells.

ABSTRACT: The forces which orient the spindle in human cells remain poorly understood due to a lack of direct mechanical measurements in mammalian systems. We use magnetic tweezers to measure the force on human mitotic spindles. Combining the spindle's measured resistance to rotation, the speed it rotates after laser ablating astral microtubules, and estimates of the number of ablated microtubules reveals that each microtubule contacting the cell cortex is subject to ~1 pN of pulling force, suggesting that each is pulled on by an individual dynein motor. We find that the concentration of dynein at the cell cortex and extent of dynein clustering are key determinants of the spindle's resistance to rotation, with little contribution from cytoplasmic viscosity, which we explain using a biophysically bas

SUBMITTER: Anjur-Dietrich MI 

PROVIDER: S-EPMC10515834 | biostudies-literature | 2023 Sep

REPOSITORIES: biostudies-literature