Figure 1. (A) At low cAMP concentrations, 14-3-3 sequesters HDAC4 in the cytosol allowing c-Jun expression (B). Gpr126 activation raises intracellular cAMP levels activating PKA. This shuttles HDAC4 into the nucleus, where it binds to the promoter of c-Jun recruiting the NCoR1/HDAC3 complex to block c-Jun expression. Then Krox20 expression drives myelin development.