Laminin-2 on the brain

Myelination involves a vast spreading of cell membrane, but the mechanism underlying this is largely unknown. On page 397, Chun et al. show that laminin-2 induces cell spreading in oligodendrocytes, the myelinating cells of the CNS, by signaling through β1 integrins and integrin-linked kinase (ILK). They also resolve an apparent difference between mice and humans. In previous studies, humans with a defect in the laminin-2 gene have shown abnormalities in both the peripheral and central nervous systems, whereas laminin-2 mutant mice appeared to have only peripheral myelination defects. In the new study the authors show that, contrary to previous reports, myelination also fails in the central nervous system (CNS) of the mutant mice.

Although the CNS of the mutant mice appears normal by conventional microscopy, electron microscopy clearly reveals myelination defects in several large clusters of small-diameter...