Browse
Submit Data
Databases
API
Help

Dataset Information

34 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

LUBAC synthesizes linear ubiquitin chains via a thioester intermediate.

ABSTRACT: The linear ubiquitin chain assembly complex (LUBAC) is a RING E3 ligase that regulates immune and inflammatory signalling pathways. Unlike classical RING E3 ligases, LUBAC determines the type of ubiquitin chain being formed, an activity normally associated with the E2 enzyme. We show that the RING-in-between-RING (RBR)-containing region of HOIP--the catalytic subunit of LUBAC--is sufficient to generate linear ubiquitin chains. However, this activity is inhibited by the N-terminal portion of the molecule, an inhibition that is released upon complex formation with HOIL-1L or SHARPIN. Furthermore, we demonstrate that HOIP transfers ubiquitin to the substrate through a thioester intermediate formed by a conserved cysteine in the RING2 domain, supporting the notion that RBR ligases act as RING/HECT hybrids.

SUBMITTER: Stieglitz B

PROVIDER: S-EPMC3432797 | biostudies-literature | 2012 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

LUBAC synthesizes linear ubiquitin chains via a thioester intermediate.

Stieglitz Benjamin B Morris-Davies Aylin C AC Koliopoulos Marios G MG Christodoulou Evangelos E Rittinger Katrin K

EMBO reports 20120713 9

The linear ubiquitin chain assembly complex (LUBAC) is a RING E3 ligase that regulates immune and inflammatory signalling pathways. Unlike classical RING E3 ligases, LUBAC determines the type of ubiquitin chain being formed, an activity normally associated with the E2 enzyme. We show that the RING-in-between-RING (RBR)-containing region of HOIP--the catalytic subunit of LUBAC--is sufficient to generate linear ubiquitin chains. However, this activity is inhibited by the N-terminal portion of the ...[more]

PMID: 22791023

Similar Datasets

The linear ubiquitin chain assembly complex (LUBAC) generates heterotypic ubiquitin chains.

Project description:The linear ubiquitin chain assembly complex (LUBAC) is the only known ubiquitin ligase for linear/Met1-linked ubiquitin chain formation. One of the LUBAC components, heme-oxidized IRP2 ubiquitin ligase 1 (HOIL-1L), was recently shown to catalyse oxyester bond formation between ubiquitin and some substrates. However, oxyester bond formation in the context of LUBAC has not been directly observed. Here, we present the first 3D reconstruction of human LUBAC obtained by electron microscopy and report its generation of heterotypic ubiquitin chains containing linear linkages with oxyester-linked branches. We found that this event depends on HOIL-1L catalytic activity. By cross-linking mass spectrometry showing proximity between the catalytic RING-in-between-RING (RBR) domains, a coordinated ubiquitin relay mechanism between the HOIL-1-interacting protein (HOIP) and HOIL-1L ligases is suggested. In mouse embryonic fibroblasts, these heterotypic chains were induced by TNF, which is reduced in cells expressing an HOIL-1L catalytic inactive mutant. In conclusion, we demonstrate that LUBAC assembles heterotypic ubiquitin chains by the concerted action of HOIP and HOIL-1L.

| S-EPMC8245127 | biostudies-literature

STING induces LUBAC-mediated synthesis of linear ubiquitin chains to stimulate innate immune signaling.

Project description:STING activation by cyclic dinucleotides in mammals induces interferon- and NFκB -related gene expression, and the lipidation of LC3B at Golgi membranes. While mechanisms of the interferon response are well understood, the mechanisms of NFκB activation mediated by STING remain unclear. We report that STING activation induces K63- and M1-linked/linear ubiquitin chain formation at LC3B-associated Golgi membranes. Loss of the LUBAC E3 ubiquitin ligase prevents formation of linear, but not K63-linked ubiquitin chains or STING activation and inhibits STING-induced NFκB and IRF3-mediated signaling in monocytic THP1 cells. The proton channel activity of STING is also important for both K63 and linear ubiquitin chain formation, and NFκB- and interferon-related gene expression. Thus, LUBAC synthesis of linear ubiquitin chains regulates STING-mediated innate immune signaling.

| S-EPMC10592814 | biostudies-literature

LUBAC-synthesized linear ubiquitin chains restrict cytosol-invading bacteria by activating autophagy and NF-?B.

Project description:Cell-autonomous immunity relies on the ubiquitin coat surrounding cytosol-invading bacteria functioning as an 'eat-me' signal for xenophagy. The origin, composition and precise mode of action of the ubiquitin coat remain incompletely understood. Here, by studying Salmonella Typhimurium, we show that the E3 ligase LUBAC generates linear (M1-linked) polyubiquitin patches in the ubiquitin coat, which serve as antibacterial and pro-inflammatory signalling platforms. LUBAC is recruited via its subunit HOIP to bacterial surfaces that are no longer shielded by host membranes and are already displaying ubiquitin, suggesting that LUBAC amplifies and refashions the ubiquitin coat. LUBAC-synthesized polyubiquitin recruits Optineurin and Nemo for xenophagy and local activation of NF-?B, respectively, which independently restrict bacterial proliferation. In contrast, the professional cytosol-dwelling Shigella flexneri escapes from LUBAC-mediated restriction through the antagonizing effects of the effector E3 ligase IpaH1.4 on deposition of M1-linked polyubiquitin and subsequent recruitment of Nemo and Optineurin. We conclude that LUBAC-synthesized M1-linked ubiquitin transforms bacterial surfaces into signalling platforms for antibacterial immunity reminiscent of antiviral assemblies on mitochondria.

| S-EPMC5576533 | biostudies-literature

The linear ubiquitin chain assembly complex LUBAC generates heterotypic ubiquitin chains

Project description:The linear ubiquitin chain assembly complex (LUBAC) is the only known ubiquitin ligase that generates linear/Met1-linked ubiquitin chains. One of the LUBAC components, HOIL-1L, was recently shown to catalyse oxyester bond formation between the C-terminus of ubiquitin and some substrates. However, oxyester bond formation in the context of LUBAC has not been directly observed. We present the first 3D reconstruction of LUBAC obtained by electron microscopy and report its generation of heterotypic ubiquitin chains containing linear linkages with oxyester-linked branches. We found that addition of the oxyester-bound branches depends on HOIL-1L catalytic activity. We suggest a coordinated ubiquitin relay mechanism between the HOIP and HOIL-1L ligases supported by cross-linking mass spectrometry data, which show proximity between the catalytic RBR domains. Mutations in the linear ubiquitin chain-binding NZF domain of HOIL-1L reduces chain branching confirming its role in the process. In cells, these heterotypic chains were induced by TNF. In conclusion, we demonstrate that LUBAC assembles heterotypic ubiquitin chains with linear and oxyester-linked branches by the concerted action of HOIP and HOIL-1L.

2021-06-28 | PXD019771 | Pride

Ufd2p synthesizes branched ubiquitin chains to promote the degradation of substrates modified with atypical chains.

Project description:Ubiquitination of a subset of proteins by ubiquitin chain elongation factors (E4), represented by Ufd2p in Saccharomyces cerevisiae, is a pivotal regulator for many biological processes. However, the mechanism of Ufd2p-mediated ubiquitination is largely unclear. Here, we show that Ufd2p catalyses K48-linked multi-monoubiquitination on K29-linked ubiquitin chains assembled by the ubiquitin ligase (Ufd4p), resulting in branched ubiquitin chains. This reaction depends on the interaction of K29-linked ubiquitin chains with two N-terminal loops of Ufd2p. Only following the addition of K48-linked ubiquitin to substrates modified with K29-linked ubiquitin chains, can the substrates be escorted to the proteasome for degradation. We demonstrate that this ubiquitin chain linkage switching reaction is essential for ERAD, oleic acid and acid pH resistance in yeast. Thus, our results suggest that Ufd2p functions by switching ubiquitin chain linkages to allow the degradation of proteins modified with a ubiquitin linkage, which is normally not targeted to the proteasome.

| S-EPMC5303827 | biostudies-literature

A20 inhibits LUBAC-mediated NF-?B activation by binding linear polyubiquitin chains via its zinc finger 7.

Project description:Linear polyubiquitination of proteins has recently been implicated in NF-?B signalling and is mediated by the linear ubiquitin chain assembly complex (LUBAC), consisting of HOIL-1, HOIP and Sharpin. However, the mechanisms that regulate linear ubiquitination are still unknown. Here, we show that A20 is rapidly recruited to NEMO and LUBAC upon TNF stimulation and that A20 inhibits LUBAC-induced NF-?B activation via its C-terminal zinc-finger 7 (ZF7) domain. Expression of a polypeptide corresponding to only ZF7 was sufficient to inhibit TNF-induced NF-?B activation. Both A20 and ZF7 can form a complex with NEMO and LUBAC, and are able to prevent the TNF-induced binding of NEMO to LUBAC. Finally, we show that ZF7 preferentially binds linear polyubiquitin chains in vitro, indicating A20-ZF7 as a novel linear ubiquitin-binding domain (LUBID). We thus propose a model in which A20 inhibits TNF- and LUBAC-induced NF-?B signalling by binding to linear polyubiquitin chains via its seventh zinc finger, which prevents the TNF-induced interaction between LUBAC and NEMO.

| S-EPMC3463847 | biostudies-literature

STING induces LUBAC synthesis of linear ubiquitin chains to activate NFkB

Project description:STING activation by cyclic dinucleotides in mammals induces Type I Interferon- and NFkB-related gene expression, and the lipidation of LC3B at Golgi membranes. While the mechanisms of the Interferon-related responses are well understood, the mechanism of NFkB activation mediated by STING activation, and how the multi-functional responses downstream of STING signaling are related remain unknown. We report that STING activation induces K63 and linear ubiquitin chain formation, and ubiquitin co-localizes with STING and LC3B at Golgi-derived vesicles. Loss of the LUBAC E3 ubiquitin ligase subunit, HOIP, prevents formation of the linear, but not K63-linked, ubiquitin chains. The ubiquitin and LC3B binding proteins, Optineurin and TNIP1, are co-localized with STING activation-induced, perinuclear LC3B foci via their UBAN domains, however loss of HOIP does not influence this localization, indicating they may bind the K63-linked ubiquitin chains. HOIP-mediated linear ubiquitin chains are well established to mediate NFkB downstream of TNFa and IL1beta receptor stimulation. Loss of HOIP in monocytic THP-1 cells inhibits STING-induced NFkB activation and NFkB-related gene transcription, as well as Interferon-related transcription. Further, the recently reported proton channel activity of STING that blocks LC3B lipidation at Golgi membranes is also important for both K63 and Linear ubiquitin chain formation, and NFkB signaling. Thus, STING induces HOIP and linear ubiquitin chain formation to activate NFkB.

| MSV000092940 | MassIVE

Linear ubiquitin chains: enzymes, mechanisms and biology.

Project description:Ubiquitination is a versatile post-translational modification that regulates a multitude of cellular processes. Its versatility is based on the ability of ubiquitin to form multiple types of polyubiquitin chains, which are recognized by specific ubiquitin receptors to induce the required cellular response. Linear ubiquitin chains are linked through Met 1 and have been established as important players of inflammatory signalling and apoptotic cell death. These chains are generated by a ubiquitin E3 ligase complex called the linear ubiquitin chain assembly complex (LUBAC) that is thus far the only E3 ligase capable of forming linear ubiquitin chains. The complex consists of three subunits, HOIP, HOIL-1L and SHARPIN, each of which have specific roles in the observed biological functions of LUBAC. Furthermore, LUBAC has been found to be associated with OTULIN and CYLD, deubiquitinases that disassemble linear chains and counterbalance the E3 ligase activity of LUBAC. Gene mutations in HOIP, HOIL-1L and OTULIN are found in human patients who suffer from autoimmune diseases, and HOIL-1L mutations are also found in myopathy patients. In this paper, we discuss the mechanisms of linear ubiquitin chain generation and disassembly by their respective enzymes and review our current understanding of their biological functions and association with human diseases.

| S-EPMC5413910 | biostudies-literature

The linear ubiquitin assembly complex (LUBAC) is essential for NLRP3 inflammasome activation.

Project description:Linear ubiquitination is a newly discovered posttranslational modification that is currently restricted to a small number of known protein substrates. The linear ubiquitination assembly complex (LUBAC), consisting of HOIL-1L, HOIP, and Sharpin, has been reported to activate NF-κB-mediated transcription in response to receptor signaling by ligating linear ubiquitin chains to Nemo and Rip1. Despite recent advances, the detailed roles of LUBAC in immune cells remain elusive. We demonstrate a novel HOIL-1L function as an essential regulator of the activation of the NLRP3/ASC inflammasome in primary bone marrow-derived macrophages (BMDMs) independently of NF-κB activation. Mechanistically, HOIL-1L is required for assembly of the NLRP3/ASC inflammasome and the linear ubiquitination of ASC, which we identify as a novel LUBAC substrate. Consequently, we find that HOIL-1L(-/-) mice have reduced IL-1β secretion in response to in vivo NLRP3 stimulation and survive lethal challenge with LPS. Together, these data demonstrate that linear ubiquitination is required for NLRP3 inflammasome activation, defining the molecular events of NLRP3 inflammasome activation and expanding the role of LUBAC as an innate immune regulator. Furthermore, our observation is clinically relevant because patients lacking HOIL-1L expression suffer from pyogenic bacterial immunodeficiency, providing a potential new therapeutic target for enhancing inflammation in immunodeficient patients.

| S-EPMC4076580 | biostudies-literature

A ubiquitin ligase complex assembles linear polyubiquitin chains.

Project description:The ubiquitin system plays important roles in the regulation of numerous cellular processes by conjugating ubiquitin to target proteins. In most cases, conjugation of polyubiquitin to target proteins regulates their function. In the polyubiquitin chains reported to date, ubiquitin monomers are linked via isopeptide bonds between an internal Lys and a C-terminal Gly. Here, we report that a protein complex consisting of two RING finger proteins, HOIL-1L and HOIP, exhibits ubiquitin polymerization activity by recognizing ubiquitin moieties of proteins. The polyubiquitin chain generated by the complex is not formed by Lys linkages, but by linkages between the C- and N-termini of ubiquitin, indicating that the ligase complex possesses a unique feature to assemble a novel head-to-tail linear polyubiquitin chain. Moreover, the complex regulates the stability of Ub-GFP (a GFP fusion protein with an N-terminal ubiquitin). The linear polyubiquitin chain generated post-translationally may function as a new modulator of proteins.

| S-EPMC1618115 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data