WBP1L is a broadly expressed transmembrane adaptor protein involved in regulating hematopoietic stem cell function and T cell development. It interacts with NEDD4-family E3 ubiquitin ligases and regulates important chemokine receptor CXCR4. Using tandem affinity purification coupled with mass spectrometry, we identified novel WBP1L interactions with the IFNγ receptor and the Cullin-RING ubiquitin ligases CRL1β-TrCP1/2. We found that WBP1L interaction with the IFNγ receptor serves to downregulate proximal IFNγ receptor signaling in female macrophages, while the interaction with CRL1β-TrCP1/2 ubiquitin ligases regulates WBP1L protein levels. Disrupting this interaction, as well as inhibiting proteasome activity or neddylation, increased WBP1L protein levels, demonstrating that CRL1β-TrCP1/2 ubiquitin ligases regulate WBP1L protein abundance. These data provide important insights into the mechanisms controlling WBP1L function.

Laboratory of Leukocyte Signalling Institute of Molecular Genetics of the Czech Academy of Sciences Videnska 1083 14220 Prague Czech Republic

Laboratory of Leukocyte Signalling Institute of Molecular Genetics of the Czech Academy of Sciences Videnska 1083 14220 Prague Czech Republic; Faculty of Science Charles University Albertov 6 12800 Prague Czech Republic

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