Interaction of TAPP adapter proteins with phosphatidylinositol (3,4)-bisphosphate regulates B cell activation and autoantibody production

Nipun Jayachandran, Ivan Landego, Ian Gibson, Angela Miller, Stephan Wullschleger, Dario Alessi, Aaron Marshall

    Research output: Contribution to journalMeeting abstractpeer-review


    Activation of PI3-kinase enzymes through the BCR is essential for B cell development and function. Active PI3Ks generate D3 phosphoinositide PI(3,4)P2 that bind to signaling molecules such as TAPP (Tandem PH domain containing protein) adaptor via their C terminal PH domain. This interaction leads to translocation of TAPPs to the plasma membrane. However, the role of TAPP adaptors in regulating PI3K signaling in B cell is not completely understood. We have performed studies on TAPP mutant mice, where a mutation was introduced to the C terminal domain of both TAPP1 and TAPP2 to determine the effect of uncoupling TAPPs from PI(3,4)P2. The studies showed an enhanced B cell activation and elevated serum antibody levels in these mice, suggesting an inhibitory role associated with TAPPs in B cells. To test whether the aberrant responses observed in B cells leads to autoimmunity in these animals, we analyzed their serum and observed a progressive increase in anti-dsDNA antibodies in the aging cohort. This along with other observed characteristics such as the presence of anti-nuclear antibodies within the serum, progressive development of lymphopenia and glomerulonephritis in aged mice is reminiscent of lupus. We are currently working to define the cellular interactions involved in this autoimmune phenotype and the signaling mechanism associated with the inhibitory role of TAPPs
    Original languageEnglish
    Article number159.5
    JournalJournal of Immunology
    Issue numberSuppl.1
    Publication statusPublished - 1 May 2012


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