ABSTRACT
The plasma membrane is the site of a wide range of cellular processes including transport of molecules, signal transduction, and maintenance of cell morphology. The plasma membrane is made up of component proteins and lipids and its structure was originally described by the fluid mosaic model. This model states that both proteins and lipids move freely within the planar membrane, thus the molecules and their complexes are not static structures, but are constantly moving and rearranging. Since this model was proposed, there have been several modifications to our understanding of the membrane, based on improved biophysical characterisation and methods, and thus, a more nuanced understanding has arisen. However, in general, the diffusive properties of the membrane allow the cell to adjust the distribution of proteins within the membrane to optimise function and ensure efficient communication between different components of the cell. Diffusion within the plasma membrane is a critical process that underlies cellular ability to facilitate and regulate numerous biological processes (e.g., lipid organisation, signal transduction, cell adhesion, and migration).
