Mechanism of tension propagation in cell membranes

Abstract

The propagation of the membrane tension perturbations is a, potentially, essential mechanism of the mechanical signal transduction along surfaces of live cells. The efficiency of this process is determined by the propagation speed, which turned to be a hot and a controversial topic of the Cell Biophysics. In a stark contrast to the earlier results and expectations, the recent studies in several cell types revealed a wide range of the tension propagation speeds beginning from the strikingly low ones challenging the significance of the process and up to relatively high biologically relevant rates. The previously suggested models of the tension propagation have been based on assuming an unrealistic softness of the membranes for the stretching-compression deformations, which challenges the model ability to account for the observations. Here, we consider a different physics of the generation and the propagation of tension perturbations in cell membranes. We propose the tension to be controlled by an intra-cellular pressure and the propagation of the tension perturbations to be mediated by a membrane area redistribution between compartments, to which cell membranes are divided by the proteinic barriers, according to the picket-fence model. Using the established elastic features of cell membranes including their effective non-stretchability, this mechanism quantitatively accounts for the slowness of the propagation process and gives a natural explanation of the wide range of the observed propagation speeds. The model predictions are amenable to a direct experimental verification by controlled osmotic pressure variations.