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HOIL-1L Interacting Protein (HOIP) as an NF-κB Regulating Component of the CD40 Signaling Complex
Journal article   Open access   Peer reviewed

HOIL-1L Interacting Protein (HOIP) as an NF-κB Regulating Component of the CD40 Signaling Complex

Bruce S Hostager, Daniel K Fox, Douglas Whitten, Curtis G Wilkerson, Betty A Eipper, Victor P Francone, Paul B Rothman and John D Colgan
PloS one, Vol.5(6), p.e11380
2010
DOI: 10.1371/journal.pone.0011380
PMCID: PMC2894856
PMID: 20614026
url
https://doi.org/10.1371/journal.pone.0011380View
Published (Version of record) Open Access

Abstract

The tumor necrosis factor receptor (TNFR) superfamily mediates signals critical for regulation of the immune system. One family member, CD40, is important for the efficient activation of antibody-producing B cells and other antigen-presenting cells. The molecules and mechanisms that mediate CD40 signaling are only partially characterized. Proteins known to interact with the cytoplasmic domain of CD40 include members of the TNF receptor-associated factor (TRAF) family, which regulate signaling and serve as links to other signaling molecules. To identify additional proteins important for CD40 signaling, we used a combined stimulation/immunoprecipitation procedure to isolate CD40 signaling complexes from B cells and characterized the associated proteins by mass spectrometry. In addition to known CD40-interacting proteins, we detected SMAC/DIABLO, HTRA2/Omi, and HOIP/RNF31/PAUL/ZIBRA. We found that these previously unknown CD40-interacting partners were recruited in a TRAF2-dependent manner. HOIP is a ubiquitin ligase capable of mediating NF-κB activation through the ubiquitin-dependent activation of IKKγ. We found that a mutant HOIP molecule engineered to lack ubiquitin ligase activity inhibited the CD40-mediated activation of NF-κB. Together, our results demonstrate a powerful approach for the identification of signaling molecules associated with cell surface receptors and indicate an important role for the ubiquitin ligase activity of HOIP in proximal CD40 signaling.
Biochemistry Cell Biology Immunology Leukocyte Signaling and Gene Expression Cell Signaling and Trafficking Structures Cell Signaling Leukocyte Activation

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