Analysing Kinetochore Function in Human Cells: Spindle Checkpoint and Chromosome Congression

During cell division microtubules of the mitotic spindle segregate the duplicated chromosomes into the two daughter cells. Chromosome–microtubule attachment is mediated by kinetochores, multiprotein complexes assembled on specialized regions of the DNA. Kinetochores modulate microtubule dynamics to generate the forces necessary to power chromosome movement and regulate the spindle checkpoint. Errors in kinetochore function can cause aneuploidy, a hallmark of 80% of solid tumors in humans, suggesting a fundamental link to tumorigenesis. Human kinetochores are complex protein machines with over 100 different proteins. Here we present fixed- and live-cell-based assays used to functionally categorize kinetochore proteins with regard to spindle checkpoint activity and kinetochore–microtubule attachment.