PTEN regulates cilia through Dishevelled.

Cilia are hair-like cellular protrusions important in many aspects of eukaryotic biology. For instance, motile cilia enable fluid movement over epithelial surfaces, while primary (sensory) cilia play roles in cellular signalling. The molecular events underlying cilia dynamics, and particularly their disassembly, are not well understood.

RACK1 is a novel interaction partner of PTK7 that is required for neural tube closure.

RACK1 is an evolutionarily conserved intracellular adaptor protein that is involved in a wide range of processes including cell adhesion and migration; however, its role in vertebrate development is largely unknown. Here, we identify RACK1 as a novel interaction partner of PTK7, a regulator of planar cell polarity that is necessary for neural tube closure. RACK1 is likewise required for Xenopus neural tube closure.

PTK7 recruits dsh to regulate neural crest migration.

PTK7 regulates planar cell polarity (PCP) signaling during vertebrate neural tube closure and establishment of inner ear hair cell polarity; however, its signaling mechanism is unknown. Here, we demonstrate a new function for PTK7 in Xenopus neural crest migration and use this system in combination with in vitro assays to define the intersection of PTK7 with the non-canonical Wnt signaling pathway that regulates PCP. In vitro, using Xenopus ectodermal explants, we show that PTK7 recruits dishevelled (dsh) to the plasma membrane, a function that is dependent on the PDZ domain of dsh, as well as on the conserved kinase domain of PTK7.

Semaphorin and neuropilin expression during early morphogenesis of Xenopus laevis.

Semaphorins are major regulators of morphogenesis and are involved in a variety of processes ranging from the guidance of cell migration to the development of cancer. Since semaphorins were first characterized as repulsive neuronal guidance cues, their expression has been best documented in the nervous system. However, broader studies are lacking.