Binding of thermalized and active membrane curvature-inducing proteins

• Published in: Soft matter Vol. 17; no. 22; pp. 556 - 5573
• Main Authors: Goutaland, Quentin, van Wijland, Frédéric, Fournier, Jean-Baptiste, Noguchi, Hiroshi
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 01.01.2021
• Subjects: Binding; Chemical Sciences; Curvature; Engineering Sciences; Membranes; Phases; Physics; Proteins; Surface tension
• ISSN: 1744-683X; 1744-6848
• DOI: 10.1039/d1sm00027f

The phase behavior of a membrane induced by the binding of curvature-inducing proteins is studied by a combination of analytical and numerical approaches. In thermal equilibrium under the detailed balance between binding and unbinding, the membrane exhibits three phases: an unbound uniform flat phase (U), a bound uniform flat phase (B), and a separated/corrugated phase (SC). In the SC phase, the bound proteins form hexagonally-ordered bowl-shaped domains. The transitions between the U and SC phases and between the B and SC phases are second order and first order, respectively. At a small spontaneous curvature of the protein or high surface tension, the transition between B and SC phases becomes continuous. Moreover, a first-order transition between the U and B phases is found at zero spontaneous curvature driven by the Casimir-like interactions between rigid proteins. Furthermore, nonequilibrium dynamics is investigated by the addition of active binding and unbinding at a constant rate. The active binding and unbinding processes alter the stability of the SC phase. Using analytical and numerical approaches, we find that equilibrium binding of membrane curving proteins on a membrane generates a phase-separated and corrugated phase. Active binding shifts its stability and makes the protein aggregates porous.