Myelination: actin disassembly leads the way

Abstract

The mechanisms that drive the spiral wrapping of the myelin sheath around axons are poorly understood. Two papers in this issue of Developmental Cell demonstrate that actin disassembly, rather than actin assembly, predominates during oligodendrocyte maturation and is critical for the genesis of the central myelin sheath.

Figure 1

Schematic illustration of: A) an oligodendrocyte process at an early stage of axon ensheathment, when F-actin predominates and promotes ensheathment and B) a process actively myelinating an axon in which actin depolymerization, mediated by gelsolin and ADF/cofilin, predominates. The leading edge of the inner turn expresses F-actin subcortically whereas in regions enriched in MBP (shown in yellow) G-actin predominates, which is proposed to result from indirect activation of depolymerization.