Site-specific ubiquitination of the E3 ligase HOIP regulates apoptosis and immune signaling

ABSTRACT: HOIP, the catalytic component of the Linear Ubiquitin chain Assembly Complex (LUBAC), is a critical regulator of inflammation. However, how HOIP itself is regulated to control inflammatory responses is unclear. Here, we discover that site-specific ubiquitination of K784 within HOIP promotes Tumour Necrosis Factor (TNF)-induced inflammatory signalling. A HOIP K784R mutant is catalytically active but shows reduced induction of an NF-B reporter relative to wild type HOIP. HOIP K784 is evolutionarily conserved, equivalent to HOIP K778 in mice. We generated HoipK778R/K778R knockin mice, which show no overt developmental phenotypes; however, in response to TNF, HoipK778R/K778R mouse embryonic fibroblasts display suppressed NF-B activation and increased apoptotic markers. On the other hand, HOIP K778R enhances the TNF-induced formation of TNFR complex II, and an interaction between TNFR complex II and LUBAC. Loss of the LUBAC component SHARPIN leads to embryonic lethality in HoipK778R/K778R mice, which is rescued by knockout of TNFR1. We propose that site-specific ubiquitination of HOIP regulates a LUBAC-dependent switch between survival and apoptosis in TNF-signalling.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Embryonic Kidney Cell Line

SUBMITTER: Richard Imre  

LAB HEAD: Fumiyo Ikeda

PROVIDER: PXD021217 | Pride | 2020-08-31

REPOSITORIES: Pride