Overview of myelin, major myelin lipids, and myelin-associated proteins

Myelin is a modified cell membrane that forms a multilayer sheath around the axon. It retains the main characteristics of biological membranes, such as lipid bilayer, but differs from them in several important respects. In this review, we focus on aspects of myelin composition that are peculiar to this structure and differentiate it from the more conventional cell membranes, with special attention to its constituent lipid components and several of the most common and important myelin proteins: myelin basic protein, proteolipid protein, and myelin protein zero. We also discuss the many-fold functions of myelin, which include reliable electrical insulation of axons to ensure rapid propagation of nerve impulses, provision of trophic support along the axon and organization of the unmyelinated nodes of Ranvier, as well as the relationship between myelin biology and neurologic disease such as multiple sclerosis. We conclude with a brief history of discovery in the field and outline questions for future research.

Automated summary

Myelin is a modified cell membrane that surrounds the axon, providing electrical insulation and trophic support. It differs from other cell membranes in terms of composition, with unique lipid components and specific proteins such as myelin basic protein, proteolipid protein, and myelin protein zero. Understanding the functions of myelin is important for studying nerve impulse propagation and neurologic diseases like multiple sclerosis. Future research should focus on exploring the history of discovery in this field and addressing remaining questions.