A bacterial ribosome hibernation factor with evolutionary connections to eukaryotic protein synthesis DOI Creative Commons
Karla Helena-Bueno, Chinenye L. Ekemezie, Charlotte R. Brown

и другие.

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2022, Номер unknown

Опубликована: Ноя. 24, 2022

During starvation and stress, virtually all organisms arrest protein synthesis to conserve energy. Inactive ribosomes are converted into a dormant state, in which they protected from damage by hibernation factor proteins. In bacteria, two major families of factors have been described, but the low conservation these proteins huge diversity species, habitats, environmental stressors has confounded their discovery. this study, using proteomics cryo-EM, we identify new dormancy psychrophilic bacterium Psychrobacter urativorans . By isolating under cold-shock conditions, observe previously unknown bound ribosomal A site, protecting critical elements both decoding peptidyl transferase centers. We show that factor, term Balon, is homolog archaeo-eukaryotic translation aeRF1, providing long-predicted evolutionary “missing link” between eukaryotic bacterial machinery. Our structures reveal Balon delivered vacant actively translating EF-Tu, highlighting an unexpected role for elongation stress response. describe several unique structural motifs allow bind mRNA-independent manner, initiating mode ribosome can commence while still engaged synthesis. bioinformatic analysis shows putative Balon-encoding genes be found within stress-response operons nearly 20 % known including many human pathogens. Taken together, our work suggests Balon/EF-Tu regulated likely ubiquitous mechanism throughout kingdom. These findings call revision model inferred common hold numerous implications how understand study dormancy.

Язык: Английский

Rational design of proteasome inhibitors based on the structure of the endogenous inhibitor PI31/Fub1 DOI
Benjamin Velez, Aida Razi,

Robert D. Hubbard

и другие.

Proceedings of the National Academy of Sciences, Год журнала: 2023, Номер 120(51)

Опубликована: Дек. 13, 2023

Proteasome inhibitors are widely used anticancer drugs. The three clinically approved agents modified small peptides that preferentially target one of the proteasome’s active sites (β5) at physiologic concentrations. In addition to these drugs, there is also an endogenous proteasome inhibitor, PI31/Fub1, enters interior simultaneously yet specifically inhibit all sites. Here, we have PI31’s evolutionarily optimized inhibitory mechanisms develop a suite potent and specific β2 inhibitors. lead compound strongly inhibited growth multiple myeloma cells as standalone agent, indicating compound’s cell permeability establishing potential therapeutic in myeloma. showed strong synergy with existing β5 inhibitor bortezomib; such combination therapies might help challenges resistance severe side effects. These results represent effective method for rational structure-guided development

Язык: Английский

Процитировано

4
Pathogen‐ and host‐directed pharmacologic strategies for control of Vairimorpha (Nosema) spp. infection in honey bees DOI

Parker Parrella,

Annabelle B. Elikan,

Jonathan W. Snow

и другие.

Journal of Eukaryotic Microbiology, Год журнала: 2024, Номер unknown

Опубликована: Апрель 4, 2024

Abstract Microsporidia are obligate intracellular parasites of the Fungal Kingdom that cause widespread infections in nature, with important effects on invertebrates involved food production systems. The two microsporidian species Vairimorpha (Nosema) ceranae (and less common apis ) can individual disease honey bees and contribute to colony collapse. efficacy, safety, availability fumagillin, only drug currently approved treat microsporidia infection bees, is uncertain. In this review, we will discuss some most promising alternative strategies for mitigation spp. an emphasis by V. , now dominant infecting bees. We focus pharmacologic interventions where mechanism action known examine both pathogen‐directed host‐directed approaches. As limiting toxicity host cells has been especially emphasized treating already facing numerous stressors, disrupt pathogen‐specific targets may be advantageous. Therefore, efforts increase knowledge tools facilitating discovery such agents directed against them should prioritized.

Язык: Английский

Процитировано

1
Functional annotation of a divergent genome using sequence and structure-based homology. DOI Creative Commons
Dennis Svedberg, Rahel R. Winiger, Alexandra Berg

и другие.

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2023, Номер unknown

Опубликована: Авг. 28, 2023

Abstract Background Microsporidia are a large taxon of intracellular pathogens characterized by extraordinarily streamlined genomes with unusually high sequence divergence and many species-specific adaptations. These unique factors pose challenges for traditional genome annotation methods based on homology. As result, the microsporidian sequenced to date contain numerous genes unknown function. Recent innovations in rapid accurate structure prediction comparison, together growing amount data structural databases, provide new opportunities assist functional newly genomes. Results In this study, we established workflow that combines structure-based gene approaches employing ChimeraX plugin, allowing visual inspection manual curation. We employed high-quality telomere-to-telomere tetraploid Vairimorpha necatrix . First, 3080 predicted open reading frames, which 89 % were confirmed RNA sequencing data, used as input. Next, ColabFold was create protein predictions, followed Foldseek search matching PDB AlphaFold databases. The subsequent curation, using hits, increased accuracy quality compared results only tools. Our resulted comprehensive description V. genome, along summary most prevalent groups, such ricin B lectin family. addition, test our tool, identified functions several previously uncharacterized Encephalitozoon cuniculi genes. Conclusion tool divergent organisms employ it sequenced, shed light pathogen Lepidoptera. addition approach can serve valuable template studying other or similarly species.

Язык: Английский

Процитировано

3
The Function of Different Subunits of the Molecular Chaperone CCT in the Microsporidium Nosema bombycis: NbCCTζ Interacts with NbCCTα DOI Creative Commons

Sheng Xu,

Ying Chen,

Jingru Qi

и другие.

Journal of Fungi, Год журнала: 2024, Номер 10(3), С. 229 - 229

Опубликована: Март 20, 2024

Chaperonin containing tailless complex polypeptide 1 (CCT) is a molecular chaperone protein that consists of eight completely different subunits and assists in the folding newly synthesized peptides. The zeta subunit CCT regulatory factor for assembly cytoskeletal proteins as individuals or complexes. In this study, Nosema bombycis (NbCCTζ) identified first time. complete ORF NbCCTζ gene 1533 bp length encodes 510 amino acid polypeptide. IFA results indicate colocalized with actin β-tubulin cytoplasm during proliferative phase NbCCTα N. throughout entire life cycle. Furthermore, yeast two-hybrid assay revealed interacts NbCCTα. transcriptional level significantly downregulated by knocking down gene, while after gene. These suggest may play vital role proliferation coordinating

Язык: Английский

Процитировано

0
Ribosome clustering and surface layer reorganization in the microsporidian host-invasion apparatus DOI Creative Commons
Himanshu Sharma, Nathan Jespersen, Kai Ehrenbolger

и другие.

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2023, Номер unknown

Опубликована: Июнь 4, 2023

Abstract During host cell invasion, microsporidian spores translocate their entire cytoplasmic content through a thin, hollow superstructure known as the polar tube. To achieve this, tube transitions from compact spring-like state inside environmental spore to long needle-like capable of long-range sporoplasm delivery. The unique mechanical properties building blocks allow for an explosive transition extended and support rapid cargo translocation process. molecular structural factors enabling this ultrafast process changes during delivery are unknown. Here, we employ light microscopy in situ cryo-electron tomography visualize multiple ultrastructural states tube, allowing us evaluate kinetics its germination characterize underlying morphological transitions. We describe cargo-filled with ordered arrangement ribosomes, which cluster along thin wall, empty post-translocation reduced diameter but thicker wall. Together proteomic analysis endogenously affinity-purified tubes, our work provides comprehensive data on infection apparatus microsporidia demonstrates that ribosomes efficiently transported tubes spiral-like parallel arrangement.

Язык: Английский

Процитировано

1
High-resolution structure of mammalian PI31–20S proteasome complex reveals mechanism of proteasome inhibition DOI Open Access
Hao-Chi Hsu,

Jason Wang,

Abbey Kjellgren

и другие.

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2023, Номер unknown

Опубликована: Апрель 4, 2023

ABSTRACT Proteasome-catalyzed protein degradation mediates and regulates critical aspects of many cellular functions is an important element proteostasis in health disease. Proteasome function determined part by the types proteasome holoenzymes formed between 20S core particle that catalyzes peptide bond hydrolysis any multiple regulatory proteins to which it binds. One these regulators, PI31, was previously identified as vitro inhibitor, but neither molecular mechanism nor possible physiologic significance PI31-mediated inhibition has been clear. Here we report a high- resolution cryo-EM structure mammalian complex with PI31. The shows two copies intrinsically-disordered carboxyl-terminus PI31 are present central cavity closed-gate conformation interact catalytic sites manner blocks proteolysis substrates resists their own degradation. inhibitory polypeptide chains appear originate from monomers enter chamber opposite ends cylinder. We evidence can inhibit activity cells may serve for control proteostasis.

Язык: Английский

Процитировано

0
An unstructured proteasome inhibitor comes into focus DOI Creative Commons
Antonia A. Nemec, Robert J. Tomko

Journal of Biological Chemistry, Год журнала: 2023, Номер 299(9), С. 105145 - 105145

Опубликована: Авг. 9, 2023

The inhibitory mechanism of an intrinsically disordered proteasome inhibitor identified over 30 years ago has finally been revealed by cryo-electron microscopy Hsu et al. in a recent report the Journal Biological Chemistry. structure, coupled with biochemical and cell-based experiments, resolves lingering questions about how achieves multisite inhibition proteasomal protease activity, while raising several exciting new on nature subpopulations process.

Язык: Английский

Процитировано

0
Differential interactions of the proteasome inhibitor PI31 with constitutive and immuno-20S proteasomes DOI Creative Commons
Jason Wang,

Abbey Kjellgren,

George Demartino

и другие.

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2023, Номер unknown

Опубликована: Дек. 12, 2023

ABSTRACT PI31 ( P roteasome I nhibitor of 31 ,000 Daltons) is a 20S proteasome binding protein originally identified as an in vitro inhibitor proteolytic activity. Recently reported cryo-electron microscopy structures 20S-PI31 complexes reveal surprising structural basis for inhibition. The natively disordered proline-rich C-terminus enters the central chamber interior cylindrical and interacts directly with proteasome’s multiple catalytic threonine residues manner predicted to inhibit their enzymatic function while evading its own proteolysis. Higher eukaryotes express alternative form featuring genetically functionally distinct subunits. This expressed tissues involved immune or response certain cytokines such interferon-γ has been termed “immuno-proteasome.” We examined relative effects on constitutive immuno-20S proteasomes show that inhibits (20Si) significantly lesser degree than it (20Sc). Unlike 20Sc, 20Si hydrolyzes carboxyl-terminus this effect contributes reduced inhibitory activity towards 20Si. These results demonstrate unexpected differential interactions 20Sc document functional consequences.

Язык: Английский

Процитировано

0
A bacterial ribosome hibernation factor with evolutionary connections to eukaryotic protein synthesis DOI Creative Commons
Karla Helena-Bueno, Chinenye L. Ekemezie, Charlotte R. Brown

и другие.

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2022, Номер unknown

Опубликована: Ноя. 24, 2022

During starvation and stress, virtually all organisms arrest protein synthesis to conserve energy. Inactive ribosomes are converted into a dormant state, in which they protected from damage by hibernation factor proteins. In bacteria, two major families of factors have been described, but the low conservation these proteins huge diversity species, habitats, environmental stressors has confounded their discovery. this study, using proteomics cryo-EM, we identify new dormancy psychrophilic bacterium Psychrobacter urativorans . By isolating under cold-shock conditions, observe previously unknown bound ribosomal A site, protecting critical elements both decoding peptidyl transferase centers. We show that factor, term Balon, is homolog archaeo-eukaryotic translation aeRF1, providing long-predicted evolutionary “missing link” between eukaryotic bacterial machinery. Our structures reveal Balon delivered vacant actively translating EF-Tu, highlighting an unexpected role for elongation stress response. describe several unique structural motifs allow bind mRNA-independent manner, initiating mode ribosome can commence while still engaged synthesis. bioinformatic analysis shows putative Balon-encoding genes be found within stress-response operons nearly 20 % known including many human pathogens. Taken together, our work suggests Balon/EF-Tu regulated likely ubiquitous mechanism throughout kingdom. These findings call revision model inferred common hold numerous implications how understand study dormancy.

Язык: Английский

Процитировано

0