The Cortical Actin Cytoskeleton: A Modulator of Plasma Membrane Protein Diffusion
Linden, Tristan van der
MetadataShow full item record
The diffusion dynamics of plasma membrane proteins and lipids are highly important to the health and functioning of cells. The cortical actin cytoskeleton has been suggested to be strongly associated with membrane diffusion, as it has been shown to induce membrane compartmentalisation. However, previous studies have investigated its effect on membrane diffusion on only a limited range of membrane molecules. Therefore, this study has aimed to elucidate the role of the cortical actin cytoskeleton on the diffusion of inner leaflet-anchored proteins, transmembrane proteins and GPI-anchored proteins (GPI-APs) in the plasma membrane. Using confocal imaging and FCS, the membrane organisation and diffusion of these membrane proteins were measured in live cells treated with the cytoskeleton disrupting drugs CK666 and Cytochalasin D (CytD), and in actin cytoskeleton-free giant plasma membrane vesicles (GPMVs). These measurements have found the actin cytoskeleton to play a confining role in the diffusion of the three classes of proteins measured, as diffusion was much faster in the cell-derived GPMVs than in live cells. In live cells treated with CK666 and CytD, this effect was shown to be largest for inner leaflet-anchored proteins. Additionally, diffusion was shown to be slower and more affected by cytoskeleton disrupting drugs in CHO cells than in U2OS cells. This strongly suggests there to be cell-specific effects of the cortical actin cytoskeleton on membrane diffusion. The results presented in this study thereby highlight the importance and complexity of the cortical actin cytoskeletal mechanisms of modulating membrane protein diffusion.