Role of the IRF-1 enhancer domain in signalling polyubiquitination and degradation

Emmanuelle Pion, Vikram Narayan, Mirjam Eckert, Kathryn L Ball

    Research output: Contribution to journalArticle

    18 Citations (Scopus)

    Abstract

    The interferon regulated transcription factor IRF-1 is a tumour suppressor protein that is activated in response to viral infection and cell signalling activated by double stranded DNA lesions. IRF-1 has a short half-life (t(0.5) 20-40 min) allowing rapid changes in steady state levels by modulating its rate of degradation and/or synthesis. However, little is known about the pathway(s) leading to IRF-1 protein degradation or what determines the rate of degradation in cells. Here we establish a role for discrete motifs in the enhancer domain of IRF-1 in directing polyubiquitination and degradation. By studying the structure of the enhancer domain as related to its role in the turnover of IRF-1 we have demonstrated that this region is not subject to modification by ubiquitin but rather that it contains both an ubiquitination signal and a distinct degradation signal. Removal of the C-terminal 70 amino acids from IRF-1 inhibits both its degradation and polyubiquitination, whereas removal of the C-terminal 25 amino acids inhibits degradation of the protein but does not prevent its ubiquitination. Furthermore, consistent with the C-terminus being involved in targeting or recognition by an E3-ligase or associated protein(s) the enhancer domain can act in trans to inhibit IRF-1 ubiquitination by endogenous E3-ligase activity. The identification of structural determinants that signals IRF-1 polyubiquitination and which can be uncoupled from IRF-1 degradation lends support to the idea that the degradation of selective substrates can be regulated at multiple steps in the ubiquitin-proteasome system.
    Original languageEnglish
    Pages (from-to)1479-1487
    Number of pages9
    JournalCellular Signalling
    Volume21
    Issue number10
    DOIs
    Publication statusPublished - Oct 2009

    Fingerprint

    Ubiquitination
    Interferon Regulatory Factor-1
    Ubiquitin-Protein Ligases
    Ubiquitin
    Proteolysis
    Tumor Suppressor Proteins
    Amino Acids
    Virus Diseases
    Proteasome Endopeptidase Complex
    Interferons
    Half-Life
    DNA
    Proteins

    Cite this

    Pion, Emmanuelle ; Narayan, Vikram ; Eckert, Mirjam ; Ball, Kathryn L. / Role of the IRF-1 enhancer domain in signalling polyubiquitination and degradation. In: Cellular Signalling. 2009 ; Vol. 21, No. 10. pp. 1479-1487.
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    Role of the IRF-1 enhancer domain in signalling polyubiquitination and degradation. / Pion, Emmanuelle; Narayan, Vikram; Eckert, Mirjam; Ball, Kathryn L.

    In: Cellular Signalling, Vol. 21, No. 10, 10.2009, p. 1479-1487.

    Research output: Contribution to journalArticle

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