Pattern formation in active cytoskeletal networks

Instabilities and oscillations in isotropic active gels

“…For large values of the motor activity as measured by the rate of ATP consumption, ∆µ, the contractile action of bound motors yields a diffusive (contractile) instability of the gel. This result has been obtained earlier in models of muscle sarcomeres [20] and actin bundles [44]. Here we show that it is a generic property of active elastic media.…”

Oscillations and uniaxial mechanochemical waves in a model of an active poroelastic medium: Application to deformation patterns in protoplasmic droplets of Physarum polycephalum

“…Models assuming an active cytoplasm [2,62] provide an alternative approach for the formation of patterns in the interior of cells compared to the standard reaction-diffusion systems, which built an combination of diffusive transport of molecules in the cell with biochemical reactions between different species. Such models have been employed for example to explain cell polarity [63] or cellular division of E. coli [64].…”

Intracellular Mechanochemical Waves in an Active Poroelastic Model

“…A candidate of such a substance is calcium that is known to decrease active tension in some cellular systems like Physarum polycephalum [19]. The most remarkable aspect of the poroelastic model described in this Letter is that mechanochemical waves do naturally arise even in the absence of kinetic biochemical oscillations that were assumed to be absolutely necessary to account for contraction waves in cells in earlier work [27,33].…”

“…Two classical models have typically been used to study cell viscoelasticity, the Maxwell model and the Voigt model [22]. Whereas the cytoskeleton has been described as an active gel by employing the Maxwell model earlier [15,23], here we follow the alternative approach that assumes that the cytoskeleton is a viscoelastic solid described by the Voigt model [24][25][26][27]. We derive the active poroelastic model in one spatial dimension; for the extension to 2D, see [28].…”