The spindle fibers in cell division attach to kinetochores , which are protein structures located at the centromere region of each chromosome.

Key structure it attaches to

  • The mitotic spindle is made of microtubules that extend from opposite poles of the cell.
  • These microtubules specifically attach to kinetochores, which sit on the centromeres of chromosomes and act as the linkage between chromosomes and the spindle.

Why this attachment matters

  • Kinetochore–microtubule attachment allows the spindle to generate tension and align chromosomes at the metaphase plate so each daughter cell gets the correct set of chromosomes.
  • Errors in these attachments can lead to mis-segregation of chromosomes and aneuploidy, which is a hallmark of many cancers.

TL;DR: The spindle attaches to kinetochores on the centromeres of chromosomes to pull sister chromatids apart accurately during cell division.

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