ABSTRACT
Cell membranes exist in a dynamic state. Measurements of membrane protein and lipid diffusion provide information concerning the molecular details of protein and lipid interactions that govern membrane structure and that mediate cell-cell interactions. The human red blood cell (RBC) membrane is a unique model for studying the dynamics of membrane protein and lipid interactions, for several reasons. First, this membrane contains a limited number of well-characterized proteins and lipids (reviewed in [1,2]). Second, analogues to RBC membrane proteins have been identified in many different nonerythroid cell types (reviewed in [1]). Third, protein and lipid interactions within the RBC membrane have been found to be altered specifically in RBCs from patients with hereditary hemolytic anemias (reviewed in [3,4]). Finally, altered protein mobility and distribution may underlie the recognition of sickle and senescent RBCs by autologous antibodies and by cells of the reticuloendothelial system (RES), and thereby provide a model for cell-cell interactions. (The term RES is herein used for convenience to define cells that line the human vasculature, including vascular endothelial cells and bone marrow-derived mononuclear phagocytes).
