Signaling and adhesion activities of mammalian beta-catenin and plakoglobin in Drosophila
Abstract
The armadillo protein of Drosophila and its vertebrate homologues, beta-catenin and plakoglobin, are implicated in cell adhesion and wnt signaling. Here, we examine the conservation of these two functions by assaying the activities of mammalian beta-catenin and plakoglobin in Drosophila. We show that, in the female germ line, both mammalian beta-catenin and plakoglobin complement an armadillo mutation. We also show that shotgun mutant germ cells (which lack Drosophila E-cadherin) have a phenotype identical to that of armadillo mutant germ cells. It therefore appears that armadillo's role in the germ line is solely in a complex with Drosophila E-cadherin (possibly an adhesion complex), and both beta-catenin and plakoglobin can function in Drosophila cadherin complexes. In embryonic signaling assays, we find that plakoglobin has no detectable activity whereas beta-catenin's activity is weak. Surprisingly, when overexpressed, either in embryos or in wing imaginal disks, both beta-catenin and plakoglobin have dominant negative activity on signaling, an effect also obtained with COOH-terminally truncated armadillo. We suggest that the signaling complex, which has been shown by others to comprise armadillo and a member of the lymphoc...Continue Reading
References
Molecular cloning and amino acid sequence of human plakoglobin, the common junctional plaque protein
Citations
The tissue polarity gene nemo carries out multiple roles in patterning during Drosophila development
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