Ciliary function and Wnt signal modulation.

With the increase in complexity of morphogenetic signaling cascades over the course of evolution and the emergence of broadly ciliated organisms, the cilium seems to have acquired a role as regulator of paracrine signal transduction. Recently, several lines of evidence have provided a link between basal body and ciliary proteins and Wnt signaling. In this chapter, we will evaluate the evidence linking the basal body and cilium with the regulation of beta-catenin-dependent (canonical) and beta-catenin-independent (noncanonical) signaling processes as well as which role(s) Wnt signaling might play in ciliogenesis. In addition, we will discuss aberrant Wnt signaling could contribute to phenotypes common to most ciliopathies and why these phenotypes might be driven by loss of noncanonical rather than gain of noncanonical Wnt signaling.