Search bioRxiv⌕ Search

bioRxiv · 10.1101/2020.06.19.161133

Structure of the yeast Nup84-Nup133 complex details flexibility and reveals universal conservation of the membrane anchoring ALPS motif

Abstract

The hallmark of the eukaryotic cell is the complex endomembrane system that compartmentalizes cellular functions. Transport into and out of the nucleus, occurs through the Nuclear Pore Complex (NPC). The heptameric Nup84 or Y complex is an essential scaffolding component of the NPC. Here we report two nanobody-bound structures: the full-length Nup84-Nup133 C-terminal domain complex and the Nup133 N-terminal domain, both from S. cerevisiae. Together with previously published structures, this work enables the structural description of the entire 575 kDa Y complex, from one species. The structure of Nup84-Nup1 33CTD details the high flexibility of this dimeric unit of the Y complex. Further, the Nup133NTD contains a structurally conserved amphipathic lipid packing sensor (ALPS) motif, confirmed by liposome interaction studies. The new structures reveal important details about the function of the Y complex that affect our understanding of NPC structure and assembly.

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Nordeen, S. A., Turman, D. L., Schwartz, T. U.. 2020-06-20. Structure of the yeast Nup84-Nup133 complex details flexibility and reveals universal conservation of the membrane anchoring ALPS motif. https://doi.org/10.1101/2020.06.19.161133

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

KEEP EXPLORING

Related preprints

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↗

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↗

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↗