Cell membranes spectrin-ankyrin network

Mechanical functions of cells require interactions between integral membrane proteins and the cytoskeleton 29 The spectrin-ankyrin network comprises a general form of membrane-organizing cytoskeleton within which a variety of membrane-cytoskeletal specializations are interspersed 29 Interaction of rafts with cytoskeleton is suggested by the results of video microscopy 29... 

In erythrocytes and most other cells, the major structural link of plasma membranes to the cytoskeleton is mediated by interactions between ankyrin and various integral membrane proteins, including Cf/HCOj antiporters, sodium ion pumps and voltage-dependent sodium ion channels. Ankyrin also binds to the =100 nm, rod-shaped, antiparallel a(3 heterodimers of spectrin and thus secures the cytoskeleton to the plasma membrane. Spectrin dimers self-associate to form tetramers and further to form a polygonal network parallel to the plasma membrane (Fig. 2-9D). Neurons contain both spectrin I, also termed erythroid spectrin, and spectrin II, also termed fodrin. Spectrin II is found throughout neurons, including axons, and binds to microtubules, whereas spectrin I occurs only in the soma and dendrites. 

Cortical spectrin-actin networks are attached to the cell membrane by bivalent membrane-microfilament binding proteins such as ankyrin and band 4.1 (see Figure 5-31). 

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