Cell Surface Glycoprotein PZR Is a Major Mediator of Concanavalin A-induced Cell Signaling

ArticleinJournal of Biological Chemistry 277(10):7882-8 · April 2002with9 Reads
Impact Factor: 4.57 · DOI: 10.1074/jbc.M111914200 · Source: PubMed

    Abstract

    PZR is an immunoglobulin superfamily cell surface protein containing a pair of immunoreceptor tyrosine-based inhibitory motifs.
    As a glycoprotein, PZR displays a strong association with concanavalin A (ConA), a member of the plant lectin family. Treatment
    of several cell lines with ConA caused tyrosine phosphorylation of a major cellular protein. Immunoblotting and immunoprecipitation
    studies indicated that this protein corresponded to PZR. Tyrosine phosphorylation of PZR was accompanied by recruitment of
    SHP-2 and was inhibited by PP1, a selective inhibitor of the Src family tyrosine kinases. Furthermore, c-Src was constitutively
    associated with PZR and was activated upon treatment of cells with ConA. Moreover, tyrosine phosphorylation of PZR was markedly
    enhanced in v-Src-transformed NIH-3T3 cells and was predominant inEscherichia coli cells co-expressing c-Src. Expression of an intracellular domain-truncated form of PZR in HT-1080 cells affected cell morphology
    and had a dominant negative effect on ConA-induced tyrosine phosphorylation of PZR, activation of c-Src, and agglutination
    of the cells. Together, the data indicate that PZR is a major receptor of ConA and has an important role in cell signaling
    via c-Src. Considering the various biological activities of ConA, the study of PZR may have major therapeutic implications.