Figure 9.

Proposed model of Tnc signaling in oligodendrocytes. The model summarizes the results obtained from the present study. We propose that Tnc binds Cntn1 within lipid rafts of oligodendrocyte membranes. This complex formation results in increased phosphorylation of the regulatory tyrosine 531 of Fyn, which reduces Fyn activity. Concomitantly, Tnc stimulation impairs phosphorylation of Akt through an as-yet-unidentified receptor. Tnc, impaired Fyn, and/or Akt activation prevents increased gene expression levels of Sam68, which are necessary for effective differentiation. It remains unknown whether Tnc prevents the activation of one linear or several parallel signaling cascades via binding to additional receptors and/or by regulation of clustering of multiple receptors within the plasma membrane.