Our nervous system would be in trouble without myelin sheaths and nodes of Ranvier. No, those two things do not refer to some kind of Lord of the Rings-type silliness. They are very important components of our nervous system that ensure fast and efficient signal conduction.
Myelin sheaths are membranes that insulate the axons of many neurons. Myelin sheaths have distinct domains of ion channels and proteins, such as the nodes of Ranvier, along the axon that are required for the high speed and efficiency of signal conduction along the axon. The nodes of Ranvier, for example, are especially important for swift movement of an axon’s action potential, which jumps from node to node in a process termed staltatory conduction. A recent paper describes the importance of a cytoskeletal adaptor protein called 4.1G in regulating the localization of proteins along the axon-sheath interface. Ivanovic and colleagues found that in mice without 4.1G, adhesion proteins and neuronal proteins were mislocalized. Images above show localization of 4.1G at the same sites as two other periaxonal membrane proteins (MAG on left, Necl4 on right) in adult mouse sciatic nerves.
Ivanovic, A., Horresh, I., Golan, N., Spiegel, I., Sabanay, H., Frechter, S., Ohno, S., Terada, N., Mobius, W., Rosenbluth, J., Brose, N., & Peles, E. (2012). The cytoskeletal adapter protein 4.1G organizes the internodes in peripheral myelinated nerves originally published in the Journal of Cell Biology, 196 (3), 337-344 DOI: 10.1083/jcb.201111127