Power cell sensors come from yarn protein filaments

Where does the strength come from in the thin tentacles that allow cells to stick to surfaces and move around? This force comes from the protein fibers twisting increasingly tightly in these sensors, Write Biophysicists from the Niels Bohr Institute in Copenhagen in the Scientific Journal on Monday Nature Communications†

The tentacles are called filamentous. Other researchers have noted their twisting and turns previously, but the Danes have now elucidated the mechanism. So use it optical tweezersLaser light tweezers are used to hold microscopic objects. With these tweezers it is also possible to measure forces and motion at such a small scale.

The cell probes are 100 to 300 nanometers thick (a nanometer is one millionth of a millimeter). Each contains 10 to 30 actin filaments, elongated protein filaments. Actin filaments give the cell strength and also ensure the transport of large molecules through the cell. In the dungeon that attaches itself to a glass slide, the philippines’ legs look like the man wires of a circus tent, stretched tightly around the dungeon. Actin provides the pulling force here.

towel

The Danes discovered this by a circular motion of the actin fibers in the filamentous legs. This process is similar to squeezing a wet towel. Due to the twisting motion that makes the towel in a tight spiral, the distance between the hands at the ends becomes shorter and shorter. At a certain point, no further bending was possible without breaking the tight helix. Then the towel begins to twist into loops that further shorten the distance between both hands with each pass. The same can be seen under a microscope. The filamentous legs of the cell experiencing greater resistance shorten due to torsion of the inner actin fibers and eventually twist.

According to the researchers, the rotation of the thread legs is “nascent”, that is, it occurs spontaneously with a bundle of threads tightly packed in a thin channel. But they also found indications that the cell could direct the process. The rotation is probably driven by a motor of myosin, another important protein in the cell, which “walks” along the actin fibers, shifting them relative to each other.

Filopodia has an indispensable function for almost all cells of the body. Already at the beginning of life they participate in the development of the fetus, later in the migration of cells and throughout life they form “sensors” with which the cell can explore its environment.

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The Danish researchers wrote that thread legs are also responsible for the migration of cancer cells, which affects the ability of tumors to spread. They speculate that turning off the mucin may prevent the cancer from spreading further. However, further research will have to show if this can actually work.