Pygopus and the Wnt signaling pathway: a diverse set of connections.
Identification of Pygopus in Drosophila as a dedicated component of the Wg (fly homolog of mammalian Wnt) signaling cascade initiated many inquiries into the mechanism of its function. Surprisingly, the nearly exclusive role for Pygopus in Wg signal transduction in flies is not seen in mice, where Pygopus appears to have both Wnt-related and Wnt-independent functions. This review addresses the initial findings of Pygopus as a Wg/Wnt co-activator in light of recent data from both fly and mammalian studies. We compare and contrast the developmental phenotypes of pygopus mutants to those characterized for known Wg/Wnt transducers and explore the data regarding a role for mammalian Pygopus 2 in tumorigenesis. We further analyze the roles of the two conserved domains of Pygopus proteins in transcription, and propose a model for the molecular mechanism of Pygopus function in both Wg/Wnt signaling and Wnt-independent transcriptional regulation.
Jessen
Shannon
S
Department of Biological Chemistry, University of California, Irvine, CA, USA.
Gu
Bingnan
B
Dai
Xing
X
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D042002:Chromatin Assembly and Disassembly; D004330:Drosophila / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D019143:Evolution, Molecular; D005260:Female; D017344:Genes, Insect; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation; D009369:Neoplasms / Q000209:etiology / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013045:Species Specificity; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism*; D051155:Wnt1 Protein; D051176:beta Catenin / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D029721:Drosophila Proteins; D047908:Intracellular Signaling Peptides and Proteins; D011518:Proto-Oncogene Proteins; C521908:Pygo1 protein, mouse; D015534:Trans-Activators; D051153:Wnt Proteins; D051155:Wnt1 Protein; D051176:beta Catenin; C453400:pygo protein, Drosophila; C495570:pygopus 2 protein, mouse; C074622:wg protein, Drosophila