Red blood cells (RBCs) must have two important characteristics to carry their rule. First, their membranes must be durable to endure the sheer forces it encounters. Second, they must be flexible, in order to squeeze through small capillaries.
The fact that the RBCs can do precisely that for 120 days without any internal repair mechanisms is the consequence of the membrane skeleton architecture.
Though RBC's membrane skeleton is being researched, the exact architecture is still under debate, mostly since imaging of such biological samples requires dehydration of the samples.
The sub-membrane skeleton of RBCs is made mainly of spectrin filaments. They form an intricate but well-structured network, which has been imaged by electron microscopy. This hexagonal network has nodes made of several additional proteins, such as band 4.1 and a short actin filament. Virtually nothing is known about the dynamics of the various components, e.g. detachment and re-attachment of spectrin filaments from the nodes. We develop methods based on single-molecule fluorescence microscopy to study both the structure and dynamics of the skeleton.