CYTOSKELETAL REGULATION OF MEMBRANE-TRANSPORT EVENTS

Recent advances in our understanding of the function of various compon ents of the cytoskeleton indicate that, besides serving a structural r ole, the membrane skeleton may regulate the activity or number of tran sport proteins in the cell membrane. Abundant evidence indicates that individual proteins of the cytoskeletal system bind directly to transp ort proteins, resulting in the three-dimensional organization of a str ucture termed the membrane skeleton. This interaction between cytoskel eton and transporters can most readily be interpreted to serve a struc tural role, keeping the transporters in specific domains. However, bec ause disruption or alteration of the cytoskeletal organization can lea d to changes in transport, the interaction may play a key role in regu lating transporter activity. Elements of the cytoskeleton also interac t with components of second messenger systems. Thus, the cytoskeleton could play a regulatory role by altering the availability of signal tr ansducers or by being an integral part of the signal transduction syst em.