Cytoskeleton induced partitioning of the plasma membrane: The picket-fence model and the compartmentalized plasma membrane theory

Abstract

The development of single-particle tracking has allowed membrane researchers to observe individual movements of membrane molecules, thereby gaining new insights into the dynamics of the plasma membrane. An important example is its role in elucidating the mechanisms involved in the suppressed diffusion of proteins and lipids in the plasma membrane. It has become clear that the plasma membrane is not simply a two-dimensional fluid as is described by the Singer-Nicolson model, but rather a two-dimensional partitioned fluid (partitioned membrane theory), in which membrane molecules are temporarily confined in 30-300nm compartments. Here, we give an overview of two models that led to the establishment of the partitioned membrane theory and how together, they address the suppressed diffusion of molecules in the plasma membrane. Furthermore, we discuss potential functions of the partitioned membrane and how other membrane models fit into this theory. We hope that this review will attract the interest of readers who are not familiar with the partitioned membrane theory and that the evidence discussed here convinces readers that this theory should be accepted as a general feature of mammalian cells.