Increasingly complex: new players enter the Wnt signaling network.
Wnt proteins can activate different intracellular signaling cascades in various organisms by interacting with receptors of the Frizzled family. The first identified Wnt signaling pathway, the Wnt/beta-catenin pathway, has been studied in much detail and is highly conserved among species. As to non-canonical Wnt pathways, the current situation is more nebulous partly because the intracellular mediators of this pathway are not yet fully understood and, in some cases, even identified. However, there are increasing data that prove the existence of non-canonical Wnt signaling and demonstrate its involvement in different developmental processes. In vertebrates, Wnt-11 and Wnt-5A can activate the Wnt/JNK pathway, which resembles the planar cell polarity pathway in Drosophila. The Wnt/Ca(2+)-pathway has only been described in Xenopus and zebrafish so far and it is unclear whether it also exists in other organisms. Two recent papers provide us with new insight into non-canonical Wnt signaling by (1) presenting a new intracellular mediator of non-canonical signaling in Xenopus1 and (2) implicating the existence of an additional non-canonical Wnt signaling pathway in flies.
D000818:Animals; D019703:Calcineurin / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002465:Cell Movement; D004268:DNA-Binding Proteins / Q000378:metabolism; D004330:Drosophila; D029721:Drosophila Proteins; D051416:Focal Adhesion Protein-Tyrosine Kinases; D051157:Frizzled Receptors; D008024:Ligands; D008565:Membrane Proteins / Q000378:metabolism; D008954:Models, Biological; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D011493:Protein Kinase C / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000737:chemistry* / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism; D051153:Wnt Proteins; D014981:Xenopus; D029867:Xenopus Proteins; D029961:Zebrafish Proteins
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D051157:Frizzled Receptors; D008024:Ligands; D008565:Membrane Proteins; D050778:NFATC Transcription Factors; C494004:NFATC3 protein, Xenopus; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D043562:Receptors, G-Protein-Coupled; D014157:Transcription Factors; D051153:Wnt Proteins; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; C058784:fz protein, Drosophila; C094522:wnt8b protein, zebrafish; D011505:Protein-Tyrosine Kinases; D051416:Focal Adhesion Protein-Tyrosine Kinases; D011493:Protein Kinase C; D019703:Calcineurin; D002118:Calcium