UC San Diego

IKKβ, which is the main protein kinase in the canonical NF-κB signaling, regulates cytokine production, inflammation, cell proliferation, survival and the responses to cellular stress. In the previous research by Gallo LH. et al. [1] showed that IKKβ K171E mutant undergoes the K-63 linked ubiquitination at K147 site as well as it activates STAT3 signaling pathway. We aimed to investigate the mechanism why which the mutant IKKβ is mediating the signaling crosstalk, by investigating interacting proteins, specifically an E3 ubiquitin ligase that catalyzing the K-63linked ubiquitination of the mutant IKKβ. We utilized a new technique called BioID that enables the selective capture of proximal interacting proteins by the mutant biotin ligase fused to a protein of interest, the IKKβ K171E 4KR. Here, the results of the identified interacting proteins including E3 ubiquitin ligases which may be involved in the signaling crosstalk are shown. This project has potential to characterize the mechanism by identifying the E3 ligase, which is a promising cancer therapeutics for patients expressing activated mutants of IKKβ which were originally identified in the hematopoietic cancers patients.