Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/745331

Deubiquitination of phosphoribosyl-ubiquitin conjugates by PDE domain-containing Legionella effectors

Wan, M.·Sulpizio, A.·Akturk, A.·Beck, W. H. J.·Lanz, M.·Faca, V. M.·Smolka, M. B.·Vogel, J. P.·Mao, Y.
View original source ↗Export metadata ↓

Abstract

Posttranslational protein modification by ubiquitin (Ub) is a central eukaryotic mechanism that regulates a plethora of physiological processes. Recent studies unveiled an unconventional type of ubiquitination mediated by the SidE family of Legionella pneumophila effectors, such as SdeA, that catalyzes the conjugation of Ub to a serine residue of target proteins via a phosphoribosyl linker (hence named PR-ubiquitination). Comparable to the deubiquitinases (DUBs) in the canonical ubiquitination pathway, here we show that two Legionella effectors, named DupA (deubiquitinase for PR-ubiquitination) and DupB, reverse PR-ubiquitination by specific removal of phosphoribosyl-Ub (PR-Ub) from substrates. Both DupA and DupB are fully capable of rescuing the Golgi fragmentation phenotype caused by exogenous expression of SdeA in mammalian cells. We further show that deletion of these two genes results in significant accumulation of PR-ubiquitinated species in host cells infected with Legionella. In addition, we have identified a list of specific PR-ubiquitinated host targets and show that DupA and DupB play a role in modulating the association of PR-ubiquitinated host targets with Legionella containing vacuoles (LCV). Together, our data establish a complete PR-ubiquitination and deubiquitination cycle and demonstrate the intricate control that Legionella has over this unusual Ub-dependent posttranslational modification.\n\nStatement of significanceUbiquitination is a vital posttranslational modification in eukaryotes. A variety of microbial pathogens exploit this pathway during their infection. Legionella pneumophila, the causative bacterial pathogen of Legionnaires disease, has been show to hijack host ubiquitination pathway via a large number of effectors. Recent studies revealed a family of effectors catalyzing a novel type of Ub-dependent posttranslational modification, namely PR-ubiquitination. Here we report two new players, DupA and DupB, involved in this unconventional pathway. We found that DupA and DupB function as PR-Ub specific DUBs and play a role in regulating the PR-ubiquitination levels of host targets. Our results not only provide an expanding view of the PR-ubiquitination pathway, but may also facilitate the future identification of PR-ubiquitination pathways in eukaryotes.

Source connections

Explore related subjects

biochemistryPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Wan, M., Sulpizio, A., Akturk, A., Beck, W. H. J., Lanz, M., Faca, V. M., Smolka, M. B., Vogel, J. P., Mao, Y.. 2019-08-23. Deubiquitination of phosphoribosyl-ubiquitin conjugates by PDE domain-containing Legionella effectors. https://doi.org/10.1101/745331

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

The structures of two intermediates en route to DNA repair within a (6-4) photolyase

Pyrimidine (6-4) pyrimidone photoproducts (6-4PPs) are mutagenic DNA lesions produced when UV light crosslinks two adjacent pyrimidine bases. These lesions must be repaired to maintain genome integrity, a function executed by the (6-4) photolyase enzymes. This repair chemistry is complex, involving the transfer of a hydroxyl group from one base to another, accompanied or followed by cleavage of an interbase bond. It remains unclear how the enzyme orchestrates this reaction. Typically, models invoke a stepwise process in which an oxetane intermediate is transiently populated, but despite over thirty years of investigation, such an intermediate has never been definitively observed. Conducting dose-controlled X-ray crystallography on the (6-4) photolyase from Vibrio cholerae, we observed the transformation of 6-4PP into an oxetane species. Furthermore, we identified a previously unanticipated hemi-cleaved intermediate. The progressive transformation of 6-4PP into oxetane, hemi-cleaved, and fully repaired species requires a reexamination of the existing models of DNA repair by (6-4) photolyases.

biochemistry↗
bioRxiv2026

Endothelial protein C receptor is an entry receptor for Langya virus

Langya virus (LayV) was recently discovered in infected individuals with febrile illness and classified as a Parahenipavirus, a group of poorly understood pathogens. LayV is distantly related to Nipah henipavirus which causes recurring outbreaks with case fatality rates reaching up to 90%. No vaccines or therapeutics are approved for use in humans for any parahenipavirus or henipavirus despite their broad geographic distribution and pandemic potential. Here, we discovered that human endothelial protein C receptor (EPCR) is an entry receptor for LayV and that the tetrameric LayV attachment glycoprotein (G) binds EPCR avidly. We reveal the molecular basis of LayV G recognition of the EPCR receptor and provide a blueprint of the determinants of receptor ortholog usage. We found that human and shrew EPCR orthologs promote cell entry of LayV and of the closely related Mojiang pseudoviruses. These results along with the detection of several Parahenipaviruses in shrews set these pathogens apart from Henipaviruses, which use Pteropid fruit bats as reservoir hosts. Our data support future surveillance efforts, by enabling prediction of EPCR utilization among newly discovered Parahenipaviruses, and the development and evaluation of countermeasures targeting this emerging group of human pathogens.

biochemistry↗
bioRxiv2026

RNA-targeted aminopyridine compounds provide a new antifungal strategy

While RNA is an emerging therapeutic target class, progress is limited by a shortage of well-defined targets in which ligand binding is coupled to measurable function. The group I intron, a self-splicing ribozyme essential in fungal mitochondria but absent from humans, offers both a tractable platform for exploring first principles of small molecule-RNA targeting and a selective antifungal target. We recalibrated an intron-splicing assay to approximate cellular conditions and performed an extensive, cryo-EM-guided structure-activity relationship campaign against the Candida albicans mtLSU intron. Ligands containing a flexible diamine outperformed conformationally constrained analogues, suggesting a general principle for engaging dynamic RNA surfaces and yielding lead aminopyridine 56 (IC 21.6 nM). Compound 56 synergizes with amphotericin B against C. albicans, suggesting a path for combination therapies. RT-qPCR confirmed direct target engagement in cells. This work establishes the fungal group I intron as a viable, mechanistically distinct antifungal target and a model platform for RNA-targeted discovery.

biochemistry↗