Theory of new 'engine'

For decades biologists have known that cells use very small molecular motors to move chromosomes, mitochondria, and other organelles in the cell, but no one understands the mechanism. ' Drive these molecules to the specified location. Researchers at the University of Rochester have opened a new direction in understanding this mechanism, and those results could lead to the formation of new therapeutic methods.

Michael Wele, a biology professor, in a paper published in the December 11 issue of Cell Number, says that the mechanism to control molecular engines is quite different from what biologists predict. before. Prior to this discovery, scientists thought that some engines were attached to organelles that determine the distance and speed at which particles could move, but Welte and colleagues found that it was not. are engines, which are unidentified molecules that play a role in controlling this mechanism.

Welte said: 'The fact that molecular motors have nothing to do with controlling this movement mechanism is very surprising, and somewhat makes those who work with vitro feel insecure. It shows that we ignore something when we only study these engines in the test tube instead of living cells. '

Intracellular movement is especially important for the health of a cell. For example, during cell division, half of each cell's chromosome is located on one side of the cell while the other half moves to the other side. If this movement is disturbed, it can cause chromosomal inequality in the daughter cells. These cells can die or become cancer. Similarly, some neurons are up to 3 minutes long , producing proteins and organelles at one end and moving these important components to the other end where they are used. This is a difficult task, and any interruption in this move can create a variety of neurological diseases.

With the difficulty of studying very small motors that operate inside this cell, biologists have done basic experiments on them outside of cells in a tightly controlled environment. This led them to believe that the speed and distance a particle moved would depend on the number of motors pulling it. So scientists concluded that the cell simply attached a certain number of motors to the organ to take it to a certain distance. Although this 'multi-engine' hypothesis is very simple, its practicality in living cells has never been tested.

Welte's graduate student, Susan Tran, decided to do an experiment to test this issue. She created some fruit fly eggs that lacked a kind of molecular motor called kinesin and found that some organ particles stopped moving - this is clear evidence that kinesin is responsible for moving organelles. this. Tran then created a mutant egg, this time containing only about half the amount of kinesin engines compared to regular eggs.Compared to regular eggs, organ particles in mutant eggs move at the same speed and distance.

For decades biologists have known that cells use very small molecular motors to move chromosomes, mitochondria, and other organelles in the cell, but no one understands the mechanism. ' Drive these molecules to the specified location. (Photo: University of Rochester)

Welte needs to know whether this equivalence is because normal eggs use only half of the available kinesin engines, or only some of the main molecules control the movement of organ particles, regardless of the number of engines. To test this, Welte asked Steven Gross, a professor of cell biology at the University of California. Gross's team used a device called 'optical tweezers' to use lasers to measure the tiny forces created by the engine. The team found that normal cellular organelles were pulled with twice the force of Tran's mutant cells.

Welte said: 'This affirms that the number of organ-pulling motors does not matter. Cells use something else to control these engines. This finding opens up a vast area for research - learn what controls these engines and from which we can control them. '

Welte and his team are now looking at where in the cell the source of this signal is and how it affects the motors. Although Welte's team used fruit fly eggs, organ-moving motors are present in all animals and are used for many different tasks, including neuronal movement in humans.

Welte also pointed out that the virus, including HIV, uses the same motor to move inside cells. They first move from the invasion site to the cell nucleus, where they multiply themselves, and then introduce later generation viruses to the cell surface. If Welte and his colleagues could determine how cells can control these motives, it is likely that the occupying HIV suppressor controls these engines and therefore keeps HIV, and the germs. Other intracellular diseases, at the edge of the cell where they are unlikely to cause much damage.

The research was funded by the National Institutes of Health, with the participation of researchers from the University of Rochester, University of California Irvine, and the University of Texas at Austin.