The central nervous system (CNS) of terrestrial vertebrates underwent a prominent molecular change when a tetraspan membrane protein, myelin proteolipid protein (PLP), replaced the type I integral membrane protein, P0, as the major protein of myelin. To investigate possible reasons for this molecular switch, we genetically engineered mice to express P0 instead of PLP in CNS myelin. In the absen...

Myelinating glial cells synthesize specialized myelin proteins and deposit them in the growing myelin sheath that enwraps axons multiple times. How do axons and myelinating glial cells coordinate this spectacular cell-cell interaction? In this issue, Trajkovic et al. show that neuronal signaling regulates cell surface expression of the myelin proteolipid protein in cultured oligodendrocytes in ...

Pelizaeus-Merzbacher disease (PMD) is a rare and progressive condition affecting the central nervous system. [1] It is one of a group of gene-linked disorders known as the leukodystrophies, which are all characterised by myelin sheath abnormalities. This is due to a mutation in the gene that controls the production of a myelin protein called proteolipid protein 1 (PLP1). The exact type of PLP1 ...

Two putative human oligodendroglioma cell lines were examined for the expression of the oligodendrocyte-associated genes, 2',3'-cyclic nucleotide-3'-phosphodiesterase, myelin basic protein, myelin proteolipid proteins, and myelin-associated glycoprotein. The expression of these genes also was examined in control astrocytoma and neuroblastoma cell lines. In addition, the expression of the non-ol...

During the development of the central nervous system (CNS), oligodendrocytes wrap their plasma membrane around axons to form a multilayered stack of tightly attached membranes. Although intracellular myelin compaction and the role of myelin basic protein has been investigated, the forces that mediate the close interaction of myelin membranes at their external surfaces are poorly understood. Suc...

The mechanisms by which axonal degeneration occurs, even in the presence of apparently normal myelin sheaths, remain unknown. In this issue, Yin et al. (2016. J. Cell Biol. https://doi.org/10.1083/jcb.201607099) study mutant mice in which proteolipid protein is replaced by the peripheral myelin protein P0 and describe a number of early axonal abnormalities, which together suggest that aberrant ...