Prometaphase

Prometaphase is the phase of mitosis following prophase and preceding metaphase in eukaryotic somatic cells.

[1] Kinetochore microtubules emerging from the centrosomes at the poles (ends) of the spindle reach the chromosomes and attach to the kinetochores,[1] throwing the chromosomes into agitated motion.

Forces exerted by protein "motors" associated with spindle microtubules move the chromosomes toward the centre of the cell.Prometaphase is not always presented as a distinct part of mitosis.

In sources that do not use the term, the events described here are instead assigned to late prophase and early metaphase.

This prevents premature progression into anaphase by inhibiting the anaphase-promoting complex until all kinetochores are attached and all the chromosomes aligned.