Myelin architecture: zippering membranes tightly together

Cell Mol Life Sci. 2014 Apr;71(7):1265-77. doi: 10.1007/s00018-013-1492-0. Epub 2013 Oct 29.

Abstract

Rapid nerve conduction requires the coating of axons by a tightly packed multilayered myelin membrane. In the central nervous system, myelin is formed from cellular processes that extend from oligodendrocytes and wrap in a spiral fashion around an axon, resulting in the close apposition of adjacent myelin membrane bilayers. In this review, we discuss the physical principles underlying the zippering of the plasma membrane of oligodendrocytes at the cytoplasmic and extracellular leaflet. We propose that the interaction of the myelin basic protein with the cytoplasmic leaflet of the myelin bilayer triggers its polymerization into a fibrous network that drives membrane zippering and protein extrusion. In contrast, the adhesion of the extracellular surfaces of myelin requires the down-regulation of repulsive components of the glycocalyx, in order to uncover weak and unspecific attractive forces that bring the extracellular surfaces into close contact. Unveiling the mechanisms of myelin membrane assembly at the cytoplasmic and extracelluar sites may help to understand how the myelin bilayers are disrupted and destabilized in the different demyelinating diseases.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Amino Acid Sequence
  • Cell Membrane / metabolism*
  • Cell Membrane / ultrastructure
  • Demyelinating Diseases / metabolism
  • Demyelinating Diseases / pathology
  • Models, Biological*
  • Molecular Sequence Data
  • Myelin Basic Protein / chemistry
  • Myelin Basic Protein / metabolism*
  • Myelin Proteolipid Protein / metabolism
  • Myelin Proteolipid Protein / physiology
  • Myelin Sheath / chemistry
  • Myelin Sheath / physiology*
  • Myelin Sheath / ultrastructure
  • Oligodendroglia / cytology
  • Oligodendroglia / metabolism
  • Sequence Alignment

Substances

  • Myelin Basic Protein
  • Myelin Proteolipid Protein