The divergent Caenorhabditis elegans beta-catenin proteins BAR-1, WRM-1 and HMP-2 make distinct protein interactions but retain functional redundancy in vivo.
beta-Catenins function both in cell adhesion as part of the cadherin/catenin complex and in Wnt signal transduction as transcription factors. Vertebrates express two related proteins, beta-catenin and plakoglobin, while Drosophila has a single family member, Armadillo. Caenorhabditis elegans expresses three beta-catenin-related proteins, BAR-1, HMP-2, and WRM-1, which are quite diverged ... in sequence from each other and other beta-catenins. While BAR-1 and WRM-1 are known to act in Wnt-mediated processes, and HMP-2 acts in a complex with cadherin/alpha-catenin homologs, it is unclear whether all three proteins retain the other functions of beta-catenin. Here we show that BAR-1, like vertebrate beta-catenin, has redundant transcription activation domains in its amino- and carboxyl-terminal regions but that HMP-2 and WRM-1 also possess the ability to activate transcription. We show via yeast two-hybrid analysis that these three proteins display distinct patterns of protein interactions. Surprisingly, we find that both WRM-1 and HMP-2 can substitute for BAR-1 in C. elegans when expressed from the bar-1 promoter. Therefore, although their mutant phenotypes and protein interaction patterns strongly suggest that the functions of beta-catenin in other species have been segregated among three diverged proteins in C. elegans, these proteins still retain sufficient similarity to display functional redundancy in vivo.
Mesh Terms:
Animals, Caenorhabditis elegans, Caenorhabditis elegans Proteins, Cell Adhesion, Cytoskeletal Proteins, Databases as Topic, Dose-Response Relationship, Drug, Models, Genetic, Oligonucleotides, Phenotype, Phylogeny, Protein Binding, Protein Structure, Tertiary, Trans-Activators, Transcription Factors, Transcription, Genetic, Transcriptional Activation, Two-Hybrid System Techniques, beta Catenin
Animals, Caenorhabditis elegans, Caenorhabditis elegans Proteins, Cell Adhesion, Cytoskeletal Proteins, Databases as Topic, Dose-Response Relationship, Drug, Models, Genetic, Oligonucleotides, Phenotype, Phylogeny, Protein Binding, Protein Structure, Tertiary, Trans-Activators, Transcription Factors, Transcription, Genetic, Transcriptional Activation, Two-Hybrid System Techniques, beta Catenin
Genetics
Date: Sep. 01, 2001
PubMed ID: 11560894
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