Monday, November 28, 2011
BGU study: Protein ‘nano-engines’ can move forward and back
Findings could aid cancer research, medicine and technology.
Tiny bits of proteins necessary for cells to divide have been found by Israeli and German scientists to have an astonishing ability to go into reverse as if they were car-like “nanoengines.”
According to a 13-page article just published in the online edition of the EMBO (European Molecular Biology Organization Journal) and due to be published in the December 14 print edition, the discovery could be vital for the understanding of biological motors during cell division, not only for basic cell science but also for cancer research and biologically inspired nanotechnology in medicine and industry. The new discoveries indicate the nanometersized molecular machines are much more powerful and versatile than previously thought.
Scientists at Ben-Gurion University of the Negev in Beersheba who have been working with a group from George August University of Goettingen, Germany, made the discovery while working on motor proteins essential for cell division.
They found these “nanoengines” can drastically modify their speed and even switch direction when loaded with a cargo - something that was not realized until now.
Cell division is a key process in the development of organisms. During regular cell division, duplicated chromosomes of the mother cell are distributed into two daughter cells. This tightly regulated process is driven by specialized enzymes called motor proteins; prominent among them are the families of kinesins and dyneins. Until now, it was believed that each member of those families was structurally programmed for a defined directionality on its track, the microtubules of the cytoskeleton. One class of motors was believed to generate motion toward the cell poles and another toward the cell equator.
But the BGU group, led by Dr. Leah (Larisa) Gheber from the clinical biochemistry and chemistry departments and the university’s Ilse Katz Institute for Nanoscale Science and Technology, along with German Prof. Christoph Schmidt, have now been able to show that one type of cell division motor in yeast cells can move in both directions. In addition, the motor protein can move toward the cell poles 10 times faster than all other known motors of the same family. The researchers observed this phenomenon with high-resolution flourescence microscopy, which was used to track single molecules both in model systems and living cells.
According, to the researchers, one particularly interesting aspect of their findings is that the bi-directional motors switch exactly into the slow forward gear when they bind between two microtubule tracks in the middle of the cell, where they help to push the chromosomes apart.
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