title: Innate immune-directed NF-κB signaling requires site-specific NEMO ubiquitination.
abstract: While the I kappa kinase (IKK) scaffolding protein NF-κB essential modulator (NEMO) binds to polyubiquitin chains to transmit inflammatory signals, NEMO itself is also ubiquitinated in response to a variety of inflammatory agonists. Although there have been hints that polyubiquitination of NEMO is essential for avoiding inflammatory disorders, the in vivo physiologic role of NEMO ubiquitination is unknown. In this work, we knock in a NEMO allele in which two major inflammatory agonist-induced ubiquitination sites cannot be ubiquitinated. We show that mice with a nonubiquitinatable NEMO allele display embryonic lethality. Heterozygous females develop inflammatory skin lesions, decreased B cell numbers, and hypercellular spleens. Embryonic lethality can be complemented by mating onto a TNFR1(-/-) background, at the cost of severe steatohepatitis and early mortality, and we also show that NEMO ubiquitination is required for optimal innate immune signaling responses. These findings suggest that NEMO ubiquitination is crucial for NF-κB activity in response to innate immune agonists.
authors.affiliation: Department of Pathology, Case Western Reserve School of Medicine, Cleveland, OH 44106, USA.
authors.forename: Janice C
authors.initials: JC
authors.lastname: Jun
authors.forename: Sylvia
authors.initials: S
authors.lastname: Kertesy
authors.forename: Mark B
authors.initials: MB
authors.lastname: Jones
authors.forename: Jill M
authors.initials: JM
authors.lastname: Marinis
authors.forename: Brian A
authors.initials: BA
authors.lastname: Cobb
authors.forename: Justine T
authors.initials: JT
authors.lastname: Tigno-Aranjuez
authors.forename: Derek W
authors.initials: DW
authors.lastname: Abbott
mesh_terms: D000818:Animals; D005260:Female; D055879:Gene Knock-In Techniques; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D016328:NF-kappa B / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology; D054875:Ubiquitination / Q000276:immunology
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; C514981:NEMO protein, mouse; D016328:NF-kappa B