Myelin-associated glycoprotein inhibits microtubule assembly by a Rho-kinase-dependent mechanism

Fumiaki Mimura, Satoru Yamagishi, Nariko Arimura, Masashi Fujitani, Takekazu Kubo, Kozo Kaibuchi, Toshihide Yamashita

Research output: Contribution to journalArticle

115 Citations (Scopus)

Abstract

Myelin-associated glycoprotein (MAG) and Nogo are potent inhibitors of neurite outgrowth from a variety of neurons, and they have been identified as possible components of the central nervous system myelin that prevents axonal regeneration in the adult vertebrate central nervous system. The activation of RhoA and Rho-kinase is reported to be an essential part of the signaling mechanism of these proteins. Here, we report that the collapsing response mediator protein-2 (CRMP-2) is phosphorylated by a Rho-kinase-dependent mechanism downstream ofMAGorNogo-66. The overexpression of the nonphosphorylated form of CRMP-2 at threonine 555, which is the phosphorylation site for Rho-kinase, counteracts the inhibitory effect of MAG on the postnatal cerebellar neurons. Additionally, the expression of the dominant negative form of CRMP-2 or knockdown of the gene using small interference RNA (siRNA) mimics the effect of MAG in vitro. Consistent with the function of CRMP-2, which promotes microtubule assembly, microtubule levels are down-regulated in the cerebellar neurons that are stimulated with MAG in vitro. Reduction in the density of microtubules is also observed in the injured axons following the spinal cord injury, and this effect depends on the Rho-kinase activity. Our data suggest the important roles of CRMP-2 and microtubules in the inhibition of the axon regeneration by the myelin-derived inhibitors.

Original languageEnglish
Pages (from-to)15970-15979
Number of pages10
JournalJournal of Biological Chemistry
Volume281
Issue number23
DOIs
Publication statusPublished - 09-06-2006

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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