Elongator's toxin-target (TOT) function is nuclear localization sequence dependent and suppressed by post-translational modification

Lars Fichtner, Daniel Jablonowski, Angelika Schierhorn, Hiroko K. Kitamoto, Michael J. R. Stark, Raffael Schaffrath

    Research output: Contribution to journalArticle

    79 Citations (Scopus)

    Abstract

    The toxin target (TOT) function of the Saccharomyces cerevisiae Elongator complex enables Kluyveromyces lactis zymocin to induce a G1 cell cycle arrest. Loss of a ubiquitin-related system (URM1-UBA4) and KTI11 enhances post-translational modification/proteolysis of Elongator subunit Tot1p (Elp1p) and abrogates its TOT function. Using TAP tagging, Kti11p contacts Elongator and translational proteins (Rps7Ap, Rps19Ap Eft2p, Yil103wp, Dph2p). Loss of YIL103w and DPH2 (involved in diphtheria toxicity) suppresses zymocicity implying that both toxins overlap in a manner mediated by Kti11p. Among the pool that co-fractionates with RNA polymerase II (pol II) and nucleolin, Nop1p, unmodified Tot1p dominates. Thus, modification/proteolysis may affect association of Elongator with pol II or its localization. Consistently, an Elongator-nuclear localization sequence (NLS) targets green fluorescent protein (GFP) to the nucleus, and its truncation yields TOT deficiency. Similarly, KAP120 deletion rescues cells from zymocin, suggesting that Elongator's TOT function requires NLS- and karyopherin-dependent nuclear import.

    Original languageEnglish
    Pages (from-to)1297-307
    Number of pages11
    JournalMolecular Microbiology
    Volume49
    Issue number5
    DOIs
    Publication statusPublished - Sep 2003

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