(ORDO NEWS) — A cage is not an island. Each of them has many ways to detect their surroundings and even physically contact neighbors or enemies using strange cellular appendages.
These tentacle-like protrusions are called filopodia, and the new study has given us a better understanding of how they allow cells to move around by twisting the skeletal inner frame.
“These structures play a key role … allowing cells to explore the environment, generate mechanical forces, carry out chemical signaling, or transmit signals through intercellular tunneling nanobridges,” the researchers write in their paper.
“The dynamics of filopodia appears to be quite complex as they display rich behaviors consisting of bending, stretching, changing length and shape. Here we show that filopodia further explore their three-dimensional extracellular space by combining growth and contraction with axial twisting and bending of their actin-rich nucleus “.
This nucleus is made up of proteins called actin and myosin. A team led by biophysicists at the Niels Bohr Institute in Denmark compares this newly discovered twisting and bending movement to a rubber band.
When twisted, the elastic shrinks and is suddenly able to move on its own, returning to its original, untwisted configuration.
In the cores of filopodia, myosin proteins wind around actin proteins, twisting them into spirals or bends. Through this movement, cell “tentacles” can sense the environment, interact with other cells or microorganisms, and even move.
“They are able to bend – twist if you like – in such a way that they can explore the entire space around the cell and even penetrate the tissues that are in their environment,” says lead author of the work, Niels Bohr Institute biophysicist Natasha Leinse.
The team used optical tweezers and a confocal microscope to physically observe actin and myosin rolls twisting; they then built a physical model to confirm that the movement occurs spontaneously due to the fact that these molecules are trapped in narrow channels within the filopodia.
Optical tweezers are an amazing technique in which perfectly calibrated laser beams hold a tiny object in place. In this case, optical tweezers were used on a tiny bead, to which the filopodium grew and then stuck, holding the “tentacle” in place.
The researchers used a variety of cells to confirm that this is not an isolated phenomenon – they studied everything from human breast cancer cells to human embryonic kidney cells.
The presence of these structures in a large number of cells means that this could be another avenue for studying diseases such as cancer.
“Cancer cells are highly invasive. And there is reason to believe that they are especially dependent on the efficiency of their filopodia in terms of learning about their environment and facilitating spread,” says Niels Bohr Institute biophysicist Poul Martin Bendix.
“Thus, it can be assumed that by finding ways to suppress the filopodia of cancer cells, it is possible to stop their growth.”
This will require a lot of research – at present, scientists are only observing this process, but learning something new about our own cells is always an exciting part of basic research.
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