Defective immuno- and thymoproteasome assembly causes severe immunodeficiency

Irina Treise, Eva M. Huber, Tanja Klein-Rodewald, Wolfgang Heinemeyer, Simon A. Grassmann, Michael Basler, Thure Adler, Birgit Rathkolb, Laura Helming, Christian Andres, Matthias Klaften, Christina Landbrecht, Thomas Wieland, Tim M. Strom, Kathy D. McCoy, Andrew J. Macpherson, Eckhard Wolf, Marcus Groettrup, Markus Ollert, Frauke NeffValerie Gailus-Durner, Helmut Fuchs, Martin Hrabě De Angelis, Michael Groll*, Dirk H. Busch

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

8 Citations (Scopus)

Abstract

By N-ethyl-N-nitrosourea (ENU) mutagenesis, we generated the mutant mouse line TUB6 that is characterised by severe combined immunodeficiency (SCID) and systemic sterile autoinflammation in homozygotes, and a selective T cell defect in heterozygotes. The causative missense point mutation results in the single amino acid exchange G170W in multicatalytic endopeptidase complex subunit-1 (MECL-1), the β2i-subunit of the immuno- and thymoproteasome. Yeast mutagenesis and crystallographic data suggest that the severe TUB6-phenotype compared to the MECL-1 knockout mouse is caused by structural changes in the C-terminal appendage of β2i that prevent the biogenesis of immuno- and thymoproteasomes. Proteasomes are essential for cell survival, and defective proteasome assembly causes selective death of cells expressing the mutant MECL-1, leading to the severe immunological phenotype. In contrast to the immunosubunits β1i (LMP2) and β5i (LMP7), mutations in the gene encoding MECL-1 have not yet been assigned to human disorders. The TUB6 mutant mouse line exemplifies the involvement of MECL-1 in immunopathogenesis and provides the first mouse model for primary immuno- and thymoproteasome-associated immunodeficiency that may also be relevant in humans.

Original languageEnglish
Article number5975
JournalScientific Reports
Volume8
Issue number1
DOIs
Publication statusPublished - 1 Dec 2018

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