Red blood cell deformability, membrane material properties and shape: regulation by transmembrane, skeletal and cytosolic proteins and lipids.

An unusual combination of membrane properties allows the RBC to undergo extensive deformation without cell fragmentation, enabling it to effectively perform its function of oxygen delivery during its long life span in circulation. These material properties are the consequence of slow evolution-driven "engineering" which evolved a composite structure in which a plasma membrane envelope composed of amphiphilic surfactant molecules is anchored to a network of skeletal proteins through tethering sites (transmembrane proteins) in the bilayer. Explosive growth in our understanding of the primary structure of the various RBC membrane proteins, definition of specific mutations in various RBC phenotypes, and detailed biophysical characterization of membrane properties of normal and mutant RBCs has enabled development of models of the molecular and structural basis for RBC properties. In this review, we have attempted to synthesize all of this currently available information and define the contributions of various membrane components to different RBC properties.