ARL13B-mediated ciliary trafficking of INPP5E

ARL13B-mediated ciliary trafficking of INPP5E ARL13B is a ciliary-localized small GTPase with an atypical C-terminus containing a coiled coil domain and a proline rich domain (PRD) (Hori et al, 2008). Mutations in ARL13B are associated with the development of the ciliopathy Joubert's Syndrome (Cantagrel et al, 2008; Parisi et al, 2009). Studies in C. elegans and vertebrates suggest that ARL13B may play a role in stabilizing the interaction between the IFT A and B complexes and the kinesin-2 motors during anterograde traffic in the cilium (Cevik et al, 2010; Li et al, 2010; Cevik et al, 2013; reviewed in Li et al, 2012; Zhang et al, 2013). Recent work has shown an additional role for ARL13B in trafficking the inositol polyphosphate-5-phosphatase E (INPP5E) to the cilium through a network that also involves the phosphodiesterase PDE6D and the centriolar protein CEP164 (Humbert et al, 2012; Thomas et al, 2014; reviewed in Zhang et al, 2013). Mutations in INPP5E are also associated with the development of Joubert syndrome and other ciliopathies (Bielas et al, 2009; Jacoby et al, 2009; reviewed in Conduit et al, 2012).