Pellino-1

Pellino-1 (Peli1) is a RING-type E3 ubiquitin ligase positioned immediately downstream of Toll-like receptors and the interleukin-1 receptor. After IRAK1 phosphorylates and activates it, Pellino-1 builds K63-linked polyubiquitin chains on IRAK1, creating the scaffold that recruits TAK1 and the IKK complex and thereby launches NF-κB and MAPK signaling. It thus sets the amplitude of innate immune responses to microbial stimuli and has been implicated in autoimmune and inflammatory disease models, as well as in some lymphomas where Peli1 is amplified. Recombinant Pellino-1 is used to reconstitute IRAK1 ubiquitination in vitro and to screen pathway-selective anti-inflammatory inhibitors.