History of Cell Membrane Theory - Modern Research

Modern Research

Continued research has revealed some shortcomings and simplifications in the original theory. For instance, channel proteins are described as having a continuous water channel through their center, which is now known to be generally untrue (an exception being nuclear pore complexes, which have a 9 nm open water channel). Also, free diffusion on the cell surface is often limited to areas a few tens of nanometers across. These limits to lateral fluidity are due to cytoskeleton anchors, lipid phase separation and aggregated protein structures. Contemporary studies also indicate that much less of the plasma membrane is “bare” lipid than previously thought and in fact much of the cell surface may be protein-associated. In spite of these limitations, the fluid mosaic model remains a popular and often referenced general notion for the structure of biological membranes.