Fig. 12.

Regulation of ciliary protein complex formation by S-palmitoylation and association with ceramide. In this model, Arl13b and acetylated tubulin are S-palmitoylated and then bound to ceramide in the ciliary membrane at the cilium base. The two proteins form a complex that is transported with CRPs to the cilium tip. Acetylated tubulin is used to extend the growing axoneme, and Arl13b is transported back to the base. Depletion of ceramide with FB1 or inhibition of S-palmitoylation with 2BPA will disrupt binding of Arl13b and acetylated tubulin to the ciliary membrane and subsequently complex formation and transport of the two proteins to the cilium tip. 2BPA, 2-bromo palmitic acid; CRP, ceramide-rich platform; 2FB1, fumonisin B1.