Well-known Principle in Physics Applies to a Newly Discovered Biomolecular Mechanism in Mitosis

When cells divide via mitosis, their genetic information is passed onto both daughter cells--the process in which this occurs is highly complex. In this process, microtubules, which are small cylindrical protein tubes, are highly involved as they form the scaffold of the spindle apparatus. This scaffold aids in distributing the genome of the chromosomes to the two daughter cells when the cells divide. The microtubules also stabilize the spindle apparatus, where the microtubules overlap the center of each cell connecting the opposite spindle poles. When the cells divide, the microtubules have been observed to slide in relation to one another by what are called motor proteins; however, the sliding stops before the microtubules actually separate.

In general, little is known about the mechanical basis that takes place in mitosis--only small fragments have been understood. With regards to the mechanism described above, scientists did not understand what caused the microtubules to stop moving and sliding--until now. This mechanism, which is only a fragment in the entire mechanical mechanism in mitosis, can be explained by a well-known principle in physics. Gas particles in a closed container increase their pressure in response to a reduction in volume. Likewise, weakly binding proteins that accumulate between overlapping microtubules behave in the same manner; thus, counteracting the pressure between the overlapping microtubules as they slide apart. As a result, the gas-like pressure of the weakly binding proteins causes the movement of the microtubules to decelerate, and in turn stops the sliding, as well.

Scientists have demonstrated this mechanism by measuring the resulting forces using optical tweezers; thus, experimentally proving the newly found mechanism. Although the mechanism is minimal, it has been added to the entire collection of work of biological mechanisms of action. As studies continue to progress, more and more fragments of mechanisms will continue to be found, one day enabling the puzzle pieces to be finally put together.

Original Article: click here.
The actual study: click here.