Btk29A-mediated tyrosine phosphorylation of Armadillo/β-catenin promotes ring canal growth in Drosophila oogenesis

Noriko Hamada-Kawaguchi, Yasuyoshi Nishida, Daisuke Yamamoto

    Research output: Contribution to journalArticlepeer-review

    6 Citations (Scopus)

    Abstract

    Drosophila Btk29A is the ortholog of mammalian Btk, a Tec family nonreceptor tyrosine kinase whose deficit causes X-linked agammaglobulinemia in humans. The Btk29AficP mutation induces multiple abnormalities in oogenesis, including the growth arrest of ring canals, large intercellular bridges that allow the flow of cytoplasm carrying maternal products essential for embryonic development from the nurse cells to the oocyte during oogenesis. In this study, inactivation of Parcas, a negative regulator of Btk29A, was found to promote Btk29A accumulation on ring canals with a concomitant increase in the ring canal diameter, counteracting the Btk29AficP mutation. This mutation markedly reduced the accumulation of phosphotyrosine on ring canals and in the regions of cell-cell contact, where adhesion-supporting proteins such as DE-cadherin and β-catenin ortholog Armadillo (Arm) are located. Our previous in vitro and in vivo analyses revealed that Btk29A directly phosphorylates Arm, leading to its release from DE-cadherin. In the present experiments, immunohistological analysis revealed that phosphorylation at tyrosine 150 (Y150) and Y667 of Arm was diminished in Btk29AficP mutant ring canals. Overexpression of an Arm mutant with unphosphorylatable Y150 inhibited ring canal growth. Thus Btk29A-induced Y150 phosphorylation is necessary for the normal growth of ring canals. We suggest that the dissociation of tyrosine-phosphorylated Arm from DE-cadherin allows dynamic actin to reorganize, leading to ring canal expansion and cell shape changes during the course of oogenesis.

    Original languageEnglish
    Article numbere0121484
    JournalPloS one
    Volume10
    Issue number3
    DOIs
    Publication statusPublished - 2015 Mar 24

    ASJC Scopus subject areas

    • Biochemistry, Genetics and Molecular Biology(all)
    • Agricultural and Biological Sciences(all)
    • General

    Fingerprint Dive into the research topics of 'Btk29A-mediated tyrosine phosphorylation of Armadillo/β-catenin promotes ring canal growth in Drosophila oogenesis'. Together they form a unique fingerprint.

    Cite this