Editors' ChoiceDevelopment

Wrap Me, Please

Science's STKE  21 Mar 2006:
Vol. 2006, Issue 327, pp. tw100
DOI: 10.1126/stke.3272006tw100

Communication is definitely essential during neuronal development when oligodendrocytes wrap neuronal axons in the myelin sheath that insulates some axons and enhances conductance of neuronal impulses. Trajkovic et al. used primary mouse cells or an immortalized oligodendroglial precursor cell line in culture to investigate how this interaction is regulated. They monitored proteolipid proteins (PLPs), a major constituent of the myelin sheath, by confocal immunofluorescence microscopy and found that, if neurons were not present, PLP was localized in the late endosome-lysome (LEs-Ls) compartment. However, when neuronal cells and oligodendrocytes were cultured together for 2 days, PLP was lost from the LEsLs. In live cell imaging experiments of cells stably expressing fluorescently tagged PLP, the authors observed that, when oligodendrocytes had been cultured for 6 to 12 hours with neurons, vesicles containing PLP became more mobile and fused with the plasma membrane. If the neuronal cells and oligodendrocytes were cultured together but not allowed to touch, diffusible factors appeared to be sufficient to stimulate redistribution of PLP to the cell surface of the oligodendrocytes. Thus, in these cells, the endocytic compartment serves as a storage location for large amounts of membrane required during myelination, and mobilization of the stored material occurs in response to communication between the neurons and oligodendrocytes.

K. Trajkovic, A. S. Dhaunchak, J. T. Goncalves, D. Wenzel, A. Schneider, G. Bunt, K.-A. Nave, M. Simons, Neuron to glia signaling triggers myelin membrane exocytosis from endosomal storage sites. J. Cell Biol. 172, 937-948 (2006). [Abstract] [Full Text]