Many key cellular processes rely on the physical interplay between biological components to perform functions. The "parts list" in these processes is similar: Microtubules, semi-rigid tubes of protein, can serve within the cell as scaffolding, roadways, and a building material for machinery; some proteins serve as fasteners, binding and releasing other materials; and motor proteins use chemical energy to push and pull materials along microtubules, or move the microtubules themselves.
To form the mitotic spindle, two organelles called centrosomes move into position on opposite sides of two identical sets of chromosomes massed near the center of the cell. From each of the centrosomes, a dense network of microtubules is assembled, reaching toward and around the mass of chromosomes. Some of the microtubules connect to the chromosomes, while others connect the two centrosomes, forming a cage around the chromosomes. Ideally, microtubules from each centrosome connect exclusively with one of each of the chromosomes in the set. Then the microtubules -- aided by proteins and motor proteins -- begin to shorten and move, pulling the chromosomes toward the centrosomes, until the two sets have been separated.
To read about research associated with this, see the Rensselaer Polytechnic Institute (RPI).
Posted by Dr. Tim Sandle