Probing plasma membrane dynamics at the single-molecule level

The plant plasma membrane is highly dynamic and changes multiple aspects of its organization in response to environmental and internal factors. A detailed understanding of membrane dynamics in living plant cells has remained obscure because of the limited spatial resolution of conventional optical microscopy. Recently, several single-molecule imaging approaches have been developed and used to provide valuable insights into the fundamental biochemical and biophysical properties of the plant plasma membrane, including the organization of membrane microdomains and the dynamics of single-molecule diffusion. Here we review single-molecule imaging methods, including total internal reflection fluorescence microscopy (TIRFM), fluorescence correlation spectroscopy (FCS), and super-resolution microscopy, and examine their contributions to recent progress in understanding protein dynamics and membrane organization in living plant cells.