title: The β-catenin HMP-2 functions downstream of Src in parallel with the Wnt pathway in early embryogenesis of C. elegans.
abstract: The Wnt and Src pathways are widely used signal transduction pathways in development. β-catenin is utilized in both pathways, as a signal transducer and a component of the cadherin cell adhesion complex, respectively. A C. elegans β-catenin HMP-2 is involved in cell adhesion, but its signaling role has been unknown. Here, we report that in early embryogenesis HMP-2 acts as a signaling molecule in the Src signal. During early embryogenesis in C. elegans, the Wnt and Src pathways are redundantly involved in endoderm induction at the four-cell stage and spindle orientation in an ABar blastomere. RNAi experiments demonstrated that HMP-2 functions in the Src pathway, but in parallel with the Wnt pathway in these processes. HMP-2 localized at the cell boundaries and nuclei, and its localization at cell boundaries was negatively regulated by SRC-1. In addition, HMP-2 was Tyr-phosphorylated in a SRC-1-dependent manner in vivo. Taken together, we propose that HMP-2 functions downstream of the Src signaling pathway and contribute to endoderm induction and ABar spindle orientation, in parallel with the Wnt signaling pathway.
authors.affiliation: Genome Biology Laboratory, National Institute of Genetics, 1111 Yata, Mishima, 411-8540, Japan. esumiyos@m.tohoku.ac.jp
authors.forename: Eisuke
authors.initials: E
authors.lastname: Sumiyoshi
authors.forename: Sachiko
authors.initials: S
authors.lastname: Takahashi
authors.forename: Hatsue
authors.initials: H
authors.lastname: Obata
authors.forename: Asako
authors.initials: A
authors.lastname: Sugimoto
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kohara
mesh_terms: D000818:Animals; D015153:Blotting, Western; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D047108:Embryonic Development / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D007211:Indoles; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D034622:RNA Interference; D015398:Signal Transduction / Q000502:physiology*; D051153:Wnt Proteins / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; D003598:Cytoskeletal Proteins; C442473:HMP-2 protein, C elegans; D007211:Indoles; D051153:Wnt Proteins; C007293:DAPI; D011494:Protein Kinases; C471235:SRC-1 protein, C elegans