The Role of Plasmalemmal-Cortical Anchoring on the Stability of Transmembrane Electropores

Abstract

The structure of eukaryotic cells is maintained by a network of filamentous actin anchored subjacently to the plasma membrane. This structure is referred to as the actin cortex. We present a locally constrained surface tension model for electroporation in order to address the influence of plasmalemmal-cortical anchoring on electropore dynamics. This model predicts that stable electropores are possible under certain conditions. The existence of stable electropores has been suggested in several experimental studies. The electropore radius at which stability is achieved is a function of the characteristic radii of locally constrained regions about the plasma membrane. This model opens the possibility of using actin-modifying compounds to physically manipulate cortical density, thereby manipulating electroporation dynamics. It also underscores the need to improve electroporation models further by incorporating the influence of trans-electropore ionic and aqueous flow, cortical flexibility, transmembrane protein mobility, and active cellular wound healing mechanisms.

Figure 1

(a) An electron micrograph of the cytosolic face of an erythrocyte’s plasma membrane detailing anchoring proteins (dark puntations). Adapted and reprinted with authors’ permission from Figure 3 in [49]. (b) An illustration of the geometry used in the locally-constrained surface tension model. R₀ is the characteristic size of the triangular locally constrained region and r is the radius of the electropore.

Figure 2

(a) Pore energy and (b) pore drift velocity as a function of pore radius for three different locally constrained surface tension areas associated with R₀ = 400, 500, and 600 nm.