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The living mathematical cell located Does his compass

The living cells such as bacteria or cells of our immune system are able to move through their environment. The forces necessary for these movements are due to the formation of elastic filaments of a gel actin. What physical mechanism leading to the formation of filaments in a given direction? In modeling the formation of the freeze and its mechanical properties, a team of physicists has shown that the mechanism for the emergence of a preferential direction of growth is a natural instability of the layer of frost on the rise.

In recent years, several experiments have been able to reproduce the mechanism enabling cells to move. The researchers repeated the growth of a layer of actin on microscopic beads. The formation of a film originally evenly over the surface of the ball and then, spontaneously, a preferential direction appears. The ball is then propelled in the opposite direction, leaving behind a long queue actin.

Thanks to a physical modeling, K. John and his colleagues have shown that the formation of actin accompanied by the emergence of mechanical important inside the film actin. A linkage between growth and freezing these mechanical constraints can understand the emergence of a spontaneous symmetry breaking, ie the emergence of a leadership promoted in a situation initially symmetrical. These results are being published in Physical Review Letters.

This discovery is an important step forward in understanding the basic mechanisms of cell motility, opening up many opportunities in biology and medicine: (i) accelerate the movement of fibroblasts promotes faster healing of wounds. (ii) the contrary reduce motility of cancer cells, would fight against the ravages of metastases.

Numerical simulation of the breaking of symmetry of a gel actin around a ball
Snapshots snapshots of a numerical simulation of the breaking of symmetry of a gel actin around a
ball (a) – (c) and a comet actin well developed (d).