Structure of HHARI, a RING-IBR-RING ubiquitin ligase: autoinhibition of an Ariadne-family E3 and insights into ligation mechanism

David M. Duda, Jennifer L. Olszewski, Jonathan P. Schuermann, Igor Kurinov, Darcie J. Miller, Amanda Nourse, Arno F. Alpi, Brenda A. Schulman

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    72 Citations (Scopus)

    Abstract

    A distinct mechanism for ubiquitin (Ub) ligation has recently been proposed for the RING1-IBR-RING2 (RBR) family of E3s: an N-terminal RING1 domain recruits a thioester-linked intermediate complex between Ub and the E2 UbcH7, and a structurally distinct C-terminal RING2 domain displays a catalytic cysteine required for Ub ligation. To obtain insights into RBR E3s, we determined the crystal structure of the human homolog of Ariadne (HHARI), which reveals the individual RING1, IBR, and RING2 domains embedded in superdomains involving sequences specific to the Ariadne RBR subfamily. The central IBR is flanked on one side by RING1, which is exposed and binds UbcH7. On the other side, a C-terminal autoinhibitory "Ariadne domain" masks the RING2 active site. Insights into RBR E3 mechanisms are provided by structure-based mutations that indicate distinct steps of relief from autoinhibition, Ub transfer from E2 to HHARI, and ligation from the HHARI cysteine to a terminal acceptor.

    Original languageEnglish
    Pages (from-to)1030-1041
    Number of pages12
    JournalStructure
    Volume21
    Issue number6
    DOIs
    Publication statusPublished - 4 Jun 2013

    Keywords

    • ACTIVATION
    • BINDING
    • COMPLEX
    • PROTEIN
    • CONFORMATIONAL-CHANGE
    • REVEALS
    • PARKINSONS-DISEASE
    • CONJUGATING ENZYME
    • DOMAIN
    • CRYSTAL-STRUCTURE

    Cite this

    Duda, D. M., Olszewski, J. L., Schuermann, J. P., Kurinov, I., Miller, D. J., Nourse, A., Alpi, A. F., & Schulman, B. A. (2013). Structure of HHARI, a RING-IBR-RING ubiquitin ligase: autoinhibition of an Ariadne-family E3 and insights into ligation mechanism. Structure, 21(6), 1030-1041. https://doi.org/10.1016/j.str.2013.04.019