Sci. Signal., 25 September 2012
Promoting Myelination Through PhosphorylationIn response to signals from axons in the peripheral nervous system, Schwann cells remodel their plasma membrane and wrap it around the length of the axon to produce myelin, which increases the efficiency with which axons conduct action potentials. Yamauchi et al. investigated signaling within Schwann cells and found that the guanine nucleotide exchange factor cytohesin-1 was required for efficient myelination. The tyrosine kinase Fyn phosphorylated and activated cytohesin-1, leading to activation of the guanosine triphosphatase Arf6 and changes in cellular morphology. Mice expressing a mutant cytohesin-1 devoid of the Fyn target site in Schwann cells had axons with decreased myelin thickness compared to those in their wild-type counterparts. This work identifies critical steps in the pathway leading from signals produced by neurons to myelination by Schwann cells, which could have implications for demyelinating diseases.
Citation: J. Yamauchi, Y. Miyamoto, T. Torii, S. Takashima, K. Kondo, K. Kawahara, N. Nemoto, J. R. Chan, G. Tsujimoto, A. Tanoue, Phosphorylation of Cytohesin-1 by Fyn Is Required for Initiation of Myelination and the Extent of Myelination During Development. Sci. Signal. 5, ra69 (2012).
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