IL-1 receptor-associated kinase (IRAK) is phosphorylated, ubiquitinated, and degraded upon interleukin-1 (IL-1) stimulation. In this study, we showed that IRAK can be ubiquitinated through both Lys-48- and Lys-63-linked polyubiquitin chains upon IL-1 induction. Pellino 3b is the RING-like motif ubiquitin protein ligase that promotes the Lys-63-linked polyubiquitination on IRAK. Pellino 3b-mediated Lys-63-linked IRAK polyubiquitination competed with Lys-48-linked IRAK polyubiquitination for the same ubiquitination site, Lys-134 of IRAK, thereby blocking IL-1-induced IRAK degradation. Importantly, the negative impact of Pellino 3b on IL-1-induced IRAK degradation correlated with the inhibitory effect of Pellino 3b on the IL-1-induced TAK1-dependent pathway, suggesting that a positive role of IRAK degradation in IL-1 induced TAK1 activation. Taken together, our results suggest that Pellino 3b acts as a negative regulator for IL-1 signaling by regulating IRAK degradation through its ubiquitin protein ligase activity.
SciCrunch is a data sharing and display platform. Anyone can create a custom portal where they can select searchable subsets of hundreds of data sources, brand their web pages and create their community. SciCrunch will push data updates automatically to all portals on a weekly basis. User communities can also add their own data to scicrunch, however this is not currently a free service.