Migration of neural crest cells is an elaborate process that requires the delamination of cells from an epithelium and cell movement into an extracellular matrix. In this work, it is shown for the first time that the non-canonical Wnt signalling [planar cell polarity (PCP) or Wnt-Ca2+] pathway controls migration of neural crest cells. By using specific Dsh mutants, we show that the canonical Wn...

Cumulative evidence indicates that Wnt pathways play crucial and diverse roles to assemble the neuromuscular junction (NMJ), a peripheral synapse characterized by the clustering of acetylcholine receptors (AChR) on postsynaptic densities. The molecular determinants of Wnt effects at the NMJ are still to be fully elucidated. We report here that the Wnt receptor Frizzled-9 (Fzd9) is expressed in ...

The caudomedial margin of the medial pallium, known as the cortical hem, expresses several Wnt genes that have been shown to be crucial for cortical development. We examined the expression of members of the Frizzled (mFz) family of Wnt receptors and the Secreted Frizzled Related Protein (SFRP) family of Wnt inhibitors during telencephalic development. We found that mFz-5 and mFz-8 are specifica...

The adult nervous system is plastic, allowing us to learn, remember, and forget. Experience-dependent plasticity occurs at synapses--the specialized points of contact between neurons where signaling occurs. However, the mechanisms that regulate the strength of synaptic signaling are not well understood. Here, we define a Wnt-signaling pathway that modifies synaptic strength in the adult nervous...

Embryonic development is controlled by a small set of signal transduction pathways, with vastly different phenotypic outcomes depending on the time and place of their recruitment. How the same molecular machinery can elicit such specific and distinct responses, remains one of the outstanding questions in developmental biology. Part of the answer may lie in the high inherent genetic complexity o...

Previous in vitro studies have implied that the Wnt-5a gene plays a role as a tumor suppressor. To explore the clinical relevance of this concept, 96 primary invasive breast carcinomas were stained with a novel antiWnt-5a antibody. Loss of Wnt-5a protein expression, evident in 44% of the invasive ductal carcinomas (n 59), was significantly associated with higher histological grade (P 0.01) and ...

The Wnt pathways are evolutionarily well-conserved signal transduction pathways that are known to play important roles in all Metazoans investigated to date. Here, we examine the Wnt pathway genes and target genes present in the genome of the echinoderm Strongylocentrotus purpuratus. Analysis of the Wnt genes revealed that eleven of the thirteen reported Wnt subfamilies are represented in sea u...

Wnt signaling is a highly conserved pathway crucial for development and homeostasis of multicellular organisms. Secreted Wnt ligands bind Frizzled receptors to regulate diverse processes such as axis patterning, cell division, and cell fate specification. They also serve to govern self-renewal of somatic stem cells in several adult tissues. The complexity of the pathway can be attributed to the...

Phosphatidylinositol (PI) 4-phosphate (PI(4)P) and its metabolizing enzymes serve important functions in cell signalling and membrane traffic. PI 4-kinase type IIα (PI4KIIα) regulates Wnt signalling, endosomal sorting of signalling receptors, and promotes adaptor protein recruitment to endosomes and the trans-Golgi network. Here we identify the E3 ubiquitin ligase Itch as binding partner and re...

Head formation requires simultaneous inhibition of multiple caudalizing signals during early vertebrate embryogenesis. We identified a novel antagonist against Wnt and FGF signaling for head formation, Shisa, which functions cell autonomously in the endoplasmic reticulum (ER). Shisa is specifically expressed in the prospective head ectoderm and the Spemann organizer of Xenopus gastrulae. Overex...