For example, a divergent canonical retrograde pathway proceeds through GSK3β (Shaggy) to alter microtubule assembly (Miech et al., 2008), and the FXS disease state is linked to dysregulated GSK3β (Min et al., 2009; Yuskaitis et al., 2010; Mines and Jope, 2011) and microtubule stability misregulation via Drosophila Futsch/mammalian MAP1B (Zhang et al., 2001; Lu et al., 2004; Yao et al., 2011). Here, MAP1B is linked to fragile X syndrome.