Combined Effect of Transmembrane Proteins and Cortical Cytoskeleton on the Lateral Organization of Plasma Membranes

The plasma membrane acts as a functional interface between the cytoplasm and the outer environment of a cell. The plasma membrane is composed of different types of lipids and proteins, and is underlined with a cytoskeleton meshwork. The plasma membrane of eukaryotic cell exhibits compositional heterogeneities in the form of nanoscale-lipid domains, called lipid rafts. The domains in model membranes are large micron-scale domains, larger than the nanoscale lipid rafts in the plasma membrane. In the present work, the hypothesis made earlier by Kusumi et al. has been addressed through large scale Langevin molecular dynamics simulations of a model recently developed by Laradji et al. Our systematic simulations over a range of number density of transmembrane proteins, cytoskeleton corral size, and cytoskeleton tension, show that the confinement of proteins by cytoskeleton leads to a slowing down of the kinetics of phase separation of multicomponent lipid bilayer, and may lead to microphase separation confirming the validity of the picket-fence model