RESUMEN

The ATP-independent chaperone SurA protects unfolded outer membrane proteins (OMPs) from aggregation in the periplasm of Gram-negative bacteria, and delivers them to the ß-barrel assembly machinery (BAM) for folding into the outer membrane (OM). Precisely how SurA recognises and binds its different OMP clients remains unclear. Escherichia coli SurA comprises three domains: a core and two PPIase domains (P1 and P2). Here, by combining methyl-TROSY NMR, single-molecule Förster resonance energy transfer (smFRET), and bioinformatics analyses we show that SurA client binding is mediated by two binding hotspots in the core and P1 domains. These interactions are driven by aromatic-rich motifs in the client proteins, leading to SurA core/P1 domain rearrangements and expansion of clients from collapsed, non-native states. We demonstrate that the core domain is key to OMP expansion by SurA, and uncover a role for SurA PPIase domains in limiting the extent of expansion. The results reveal insights into SurA-OMP recognition and the mechanism of activation for an ATP-independent chaperone, and suggest a route to targeting the functions of a chaperone key to bacterial virulence and OM integrity.

Asunto(s)

Proteínas de la Membrana Bacteriana Externa , Proteínas de Escherichia coli , Escherichia coli , Chaperonas Moleculares , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/química , Proteínas de la Membrana Bacteriana Externa/metabolismo , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas de la Membrana Bacteriana Externa/química , Escherichia coli/metabolismo , Escherichia coli/genética , Sitios de Unión , Chaperonas Moleculares/metabolismo , Transferencia Resonante de Energía de Fluorescencia , Unión Proteica , Adenosina Trifosfato/metabolismo , Dominios Proteicos , Pliegue de Proteína , Isomerasa de Peptidilprolil/metabolismo , Isomerasa de Peptidilprolil/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Transportadoras de Casetes de Unión a ATP/química , Transportadoras de Casetes de Unión a ATP/genética , Modelos Moleculares , Proteínas Portadoras

RESUMEN

Collagen posttranslational processing is crucial for its proper assembly and function. Disruption of collagen processing leads to tissue development and structure disorders like osteogenesis imperfecta (OI). OI-related collagen processing machinery includes prolyl 3-hydroxylase 1 (P3H1), peptidyl-prolyl cis-trans isomerase B (PPIB), and cartilage-associated protein (CRTAP), with their structural organization and mechanism unclear. We determine cryo-EM structures of the P3H1/CRTAP/PPIB complex. The active sites of P3H1 and PPIB form a face-to-face bifunctional reaction center, indicating a coupled modification mechanism. The structure of the P3H1/CRTAP/PPIB/collagen peptide complex reveals multiple binding sites, suggesting a substrate interacting zone. Unexpectedly, a dual-ternary complex is observed, and the balance between ternary and dual-ternary states can be altered by mutations in the P3H1/PPIB active site and the addition of PPIB inhibitors. These findings provide insights into the structural basis of collagen processing by P3H1/CRTAP/PPIB and the molecular pathology of collagen-related disorders.

Asunto(s)

Colágeno , Microscopía por Crioelectrón , Ciclofilinas , Proteínas de la Matriz Extracelular , Humanos , Colágeno/metabolismo , Colágeno/química , Proteínas de la Matriz Extracelular/metabolismo , Proteínas de la Matriz Extracelular/química , Proteínas de la Matriz Extracelular/genética , Ciclofilinas/metabolismo , Ciclofilinas/química , Ciclofilinas/genética , Dominio Catalítico , Isomerasa de Peptidilprolil/metabolismo , Isomerasa de Peptidilprolil/química , Isomerasa de Peptidilprolil/genética , Procesamiento Proteico-Postraduccional , Sitios de Unión , Unión Proteica , Autoantígenos/metabolismo , Autoantígenos/química , Autoantígenos/genética , Modelos Moleculares , Mutación , Osteogénesis Imperfecta/metabolismo , Osteogénesis Imperfecta/genética , Procolágeno-Prolina Dioxigenasa/metabolismo , Procolágeno-Prolina Dioxigenasa/genética , Procolágeno-Prolina Dioxigenasa/química , Glicoproteínas de Membrana , Proteoglicanos , Chaperonas Moleculares , Prolil Hidroxilasas

RESUMEN

Nuclear factor erythroid 2-related factor 2 (NRF2) hyperactivation has been established as an oncogenic driver in a variety of human cancers, including non-small cell lung cancer (NSCLC). However, despite massive efforts, no specific therapy is currently available to target NRF2 hyperactivation. Here, we identify peptidylprolyl isomerase A (PPIA) is required for NRF2 protein stability. Ablation of PPIA promotes NRF2 protein degradation and blocks NRF2-driven growth in NSCLC cells. Mechanistically, PPIA physically binds to NRF2 and blocks the access of ubiquitin/Kelch Like ECH Associated Protein 1 (KEAP1) to NRF2, thus preventing ubiquitin-mediated degradation. Our X-ray co-crystal structure reveals that PPIA directly interacts with a NRF2 interdomain linker via a trans-proline 174-harboring hydrophobic sequence. We further demonstrate that an FDA-approved drug, cyclosporin A (CsA), impairs the interaction of NRF2 with PPIA, inducing NRF2 ubiquitination and degradation. Interestingly, CsA interrupts glutamine metabolism mediated by the NRF2/KLF5/SLC1A5 pathway, consequently suppressing the growth of NRF2-hyperactivated NSCLC cells. CsA and a glutaminase inhibitor combination therapy significantly retard tumor progression in NSCLC patient-derived xenograft (PDX) models with NRF2 hyperactivation. Our study demonstrates that targeting NRF2 protein stability is an actionable therapeutic approach to treat NRF2-hyperactivated NSCLC.

Asunto(s)

Carcinoma de Pulmón de Células no Pequeñas , Proteína 1 Asociada A ECH Tipo Kelch , Neoplasias Pulmonares , Factor 2 Relacionado con NF-E2 , Isomerasa de Peptidilprolil , Estabilidad Proteica , Ubiquitinación , Animales , Femenino , Humanos , Ratones , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/patología , Carcinoma de Pulmón de Células no Pequeñas/genética , Línea Celular Tumoral , Progresión de la Enfermedad , Proteína 1 Asociada A ECH Tipo Kelch/metabolismo , Proteína 1 Asociada A ECH Tipo Kelch/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/genética , Ratones Desnudos , Factor 2 Relacionado con NF-E2/metabolismo , Proteolisis , Isomerasa de Peptidilprolil/metabolismo

RESUMEN

SlyD is a widely-occurring prokaryotic FKBP-family prolyl isomerase with an additional chaperone domain. Often, such as in Escherichia coli, a third domain is found at its C-terminus that binds nickel and provides it for nickel-enzyme biogenesis. SlyD has been found to bind signal peptides of proteins that are translocated by the Tat pathway, a system for the transport of folded proteins across membranes. Using peptide arrays to analyze these signal peptide interactions, we found that SlyD interacted only with positively charged peptides, with a preference for arginines over lysines, and large hydrophobic residues enhanced binding. Especially a twin-arginine motif was recognized, a pair of highly conserved arginines adjacent to a stretch of hydrophobic residues. Using isothermal titration calorimetry (ITC) with purified SlyD and a signal peptide-containing model Tat substrate, we could show that the wild type twin-arginine signal peptide was bound with higher affinity than an RR>KK mutated variant, confirming that positive charges are recognized by SlyD, with a preference of arginines over lysines. The specific role of negative charges of the chaperone domain surface and of hydrophobic residues in the chaperone active site was further analyzed by ITC of mutated SlyD variants. Our data show that the supposed key hydrophobic residues of the active site are indeed crucial for binding, and that binding is influenced by negative charges on the chaperone domain. Recognition of positive charges is likely achieved by a large negatively charged surface region of the chaperone domain, which is highly conserved although individual positions are variable.

Asunto(s)

Proteínas de Escherichia coli , Escherichia coli , Chaperonas Moleculares , Isomerasa de Peptidilprolil , Unión Proteica , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/química , Isomerasa de Peptidilprolil/metabolismo , Isomerasa de Peptidilprolil/genética , Escherichia coli/metabolismo , Escherichia coli/genética , Chaperonas Moleculares/metabolismo , Chaperonas Moleculares/genética , Chaperonas Moleculares/química , Señales de Clasificación de Proteína , Interacciones Hidrofóbicas e Hidrofílicas , Calorimetría , Arginina/metabolismo , Secuencia de Aminoácidos

RESUMEN

Global substitution of leucine for analogues containing CH2F instead of methyl groups delivers proteins with multiple sites for monitoring by 19F nuclear magnetic resonance (NMR) spectroscopy. The 19 kDa Escherichia coli peptidyl-prolyl cis-trans isomerase B (PpiB) was prepared with uniform high-level substitution of leucine by (2S,4S)-5-fluoroleucine, (2S,4R)-5-fluoroleucine, or 5,5'-difluoroleucine. The stability of the samples toward thermal denaturation was little altered compared to the wild-type protein. 19F nuclear magnetic resonance (NMR) spectra showed large chemical shift dispersions between 6 and 17 ppm. The 19F chemical shifts correlate with the three-bond 1H-19F couplings (3JHF), providing the first experimental verification of the γ-gauche effect predicted by [Feeney, J. J. Am. Chem. Soc. 1996, 118, 8700-8706] and establishing the effect as the predominant determinant of the 19F chemical shifts of CH2F groups. Individual CH2F groups can be confined to single rotameric states by the protein environment, but most CH2F groups exchange between different rotamers at a rate that is fast on the NMR chemical shift scale. Interactions between fluorine atoms in 5,5'-difluoroleucine bias the CH2F rotamers in agreement with results obtained previously for 1,3-difluoropropane. The sensitivity of the 19F chemical shift to the rotameric state of the CH2F groups potentially renders them particularly sensitive for detecting allosteric effects.

Asunto(s)

Proteínas de Escherichia coli , Escherichia coli , Isomerasa de Peptidilprolil , Isomerasa de Peptidilprolil/metabolismo , Isomerasa de Peptidilprolil/química , Escherichia coli/metabolismo , Escherichia coli/genética , Escherichia coli/enzimología , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Ligandos , Resonancia Magnética Nuclear Biomolecular/métodos , Leucina/química , Leucina/metabolismo , Leucina/análogos & derivados , Flúor/química

RESUMEN

Pathogenic bacteria rely on secreted virulence factors to cause disease in susceptible hosts. However, in Gram-positive bacteria, the mechanisms underlying secreted protein activation and regulation post-membrane translocation remain largely unknown. Using proteomics, we identified several proteins that are dependent on the secreted chaperone PrsA2. We followed with phenotypic, biochemical, and biophysical assays and computational analyses to examine the regulation of a detected key secreted virulence factor, listeriolysin O (LLO), and its interaction with PrsA2 from the bacterial pathogen Listeria monocytogenes (Lm). Critical to Lm virulence is internalization by host cells and the subsequent action of the cholesterol-dependent pore-forming toxin, LLO, which enables bacterial escape from the host cell phagosome. Since Lm is a Gram-positive organism, the space between the cell membrane and wall is solvent exposed. Therefore, we hypothesized that the drop from neutral to acidic pH as the pathogen is internalized into a phagosome is critical to regulating the interaction of PrsA2 with LLO. Here, we demonstrate that PrsA2 directly interacts with LLO in a pH-dependent manner. We show that PrsA2 protects and sequesters LLO under neutral pH conditions where LLO can be observed to aggregate. In addition, we identify molecular features of PrsA2 that are required for interaction and ultimately the folding and activity of LLO. Moreover, protein-complex modeling suggests that PrsA2 interacts with LLO via its cholesterol-binding domain. These findings highlight a mechanism by which a Gram-positive secretion chaperone regulates the secretion, stability, and folding of a pore-forming toxin under conditions relevant to host cell infection. IMPORTANCE: Lm is a ubiquitous food-borne pathogen that can cause severe disease to vulnerable populations. During infection, Lm relies on a wide repertoire of secreted virulence factors including the LLO that enables the bacterium to invade the host and spread from cell to cell. After membrane translocation, secreted factors must become active in the challenging bacterial cell membrane-wall interface. However, the mechanisms required for secreted protein folding and function are largely unknown. Lm encodes a chaperone, PrsA2, that is critical for the activity of secreted factors. Here, we show that PrsA2 directly associates and protects the major Lm virulence factor, LLO, under conditions corresponding to the host cytosol, where LLO undergoes irreversible denaturation. Additionally, we identify molecular features of PrsA2 that enable its interaction with LLO. Together, our results suggest that Lm and perhaps other Gram-positive bacteria utilize secreted chaperones to regulate the activity of pore-forming toxins during infection.

Asunto(s)

Toxinas Bacterianas , Proteínas de Choque Térmico , Proteínas Hemolisinas , Listeria monocytogenes , Listeriosis , Pliegue de Proteína , Proteínas Hemolisinas/metabolismo , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/química , Proteínas de Choque Térmico/metabolismo , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/química , Listeria monocytogenes/genética , Listeria monocytogenes/metabolismo , Listeria monocytogenes/patogenicidad , Listeria monocytogenes/química , Toxinas Bacterianas/metabolismo , Toxinas Bacterianas/genética , Toxinas Bacterianas/química , Listeriosis/microbiología , Factores de Virulencia/metabolismo , Factores de Virulencia/genética , Chaperonas Moleculares/metabolismo , Chaperonas Moleculares/genética , Chaperonas Moleculares/química , Isomerasa de Peptidilprolil/metabolismo , Isomerasa de Peptidilprolil/genética , Isomerasa de Peptidilprolil/química , Concentración de Iones de Hidrógeno , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/química , Estabilidad Proteica , Humanos

RESUMEN

Cyclophilin B (CypB), a significant member of immunophilins family with peptidyl-prolyl cis-trans isomerase (PPIase) activity, is crucial for the growth and metabolism of prokaryotes and eukaryotes. Sporothrix globosa (S. globosa), a principal pathogen in the Sporothrix complex, causes sporotrichosis. Transcriptomic analysis identified the cypB gene as highly expressed in S. globosa. Our previous study demonstrated that the recombinant Escherichia coli strain containing SgcypB gene failed to produce sufficient product when it was induced to express the protein, implying the potential toxicity of recombinant protein to the bacterial host. Bioinformatics analysis revealed that SgCypB contains transmembrane peptides within the 52 amino acid residues at the N-terminus and 21 amino acids near the C-terminus, and 18 amino acid residues within the cytoplasm. AlphaFold2 predicted a SgCypB 3D structure in which there is an independent PPIase domain consisting of a spherical extracellular part. Hence, we chose to express the extracellular domain to yield high-level recombinant protein with PPIase activity. Finally, we successfully produced high-yield, truncated recombinant CypB protein from S. globosa (SgtrCypB) that retained characteristic PPIase activity without host bacterium toxicity. This study presents an alternative expression strategy for proteins toxic to prokaryotes, such as SgCypB. ONE-SENTENCE SUMMARY: The recombinant cyclophilin B protein of Sporothrix globosa was expressed successfully by retaining extracellular domain with peptidyl-prolyl cis-trans isomerase activity to avoid toxicity to the host bacterium.

Asunto(s)

Ciclofilinas , Escherichia coli , Proteínas Recombinantes , Sporothrix , Sporothrix/genética , Sporothrix/enzimología , Sporothrix/efectos de los fármacos , Sporothrix/metabolismo , Ciclofilinas/genética , Ciclofilinas/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Expresión Génica , Biología Computacional , Isomerasa de Peptidilprolil/genética , Isomerasa de Peptidilprolil/metabolismo

RESUMEN

Proteins produced with leucine analogues, where CH2F groups substitute specific methyl groups, can readily be probed by 19F NMR spectroscopy. As CF and CH groups are similar in hydrophobicity and size, fluorinated leucines are expected to cause minimal structural perturbation, but the impact of fluorine on the rotational freedom of CH2F groups is unclear. We present high-resolution crystal structures of Escherichia coli peptidyl-prolyl cis-trans isomerase B (PpiB) prepared with uniform high-level substitution of leucine by (2S,4S)-5-fluoroleucine, (2S,4R)-5-fluoroleucine, or 5,5'-difluoroleucine. Apart from the fluorinated leucine residues, the structures show complete structural conservation of the protein backbone and the amino acid side chains except for a single isoleucine side chain located next to a fluorine atom in the hydrophobic core of the protein. The carbon skeletons of the fluorinated leucine side chains are also mostly conserved. The CH2F groups show a strong preference for staggered rotamers and often appear locked into single rotamers. Substitution of leucine CH3 groups for CH2F groups is thus readily tolerated in the three-dimensional (3D) structure of a protein, and the rotation of CH2F groups can be halted at cryogenic temperatures.

Asunto(s)

Leucina , Leucina/química , Escherichia coli/metabolismo , Conformación Proteica , Modelos Moleculares , Cristalografía por Rayos X , Isomerasa de Peptidilprolil/química , Isomerasa de Peptidilprolil/metabolismo , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo

RESUMEN

Disturbances in protein phase transitions promote protein aggregation─a neurodegeneration hallmark. The modular Ran-binding protein 2 (Ranbp2) is a cytosolic molecular hub for rate-limiting steps of phase transitions of Ran-GTP-bound protein ensembles exiting nuclear pores. Chaperones also regulate phase transitions and proteostasis by suppressing protein aggregation. Ranbp2 haploinsufficiency promotes the age-dependent neuroprotection of the chorioretina against phototoxicity by proteostatic regulations of neuroprotective substrates of Ranbp2 and by suppressing the buildup of polyubiquitylated substrates. Losses of peptidyl-prolyl cis-trans isomerase (PPIase) and chaperone activities of the cyclophilin domain (CY) of Ranbp2 recapitulate molecular effects of Ranbp2 haploinsufficiency. These CY impairments also stimulate deubiquitylation activities and phase transitions of 19S cap subunits of the 26S proteasome that associates with Ranbp2. However, links between CY moonlighting activity, substrate ubiquitylation, and proteostasis remain incomplete. Here, we reveal the Ranbp2 regulation of small heat shock chaperones─crystallins in the chorioretina by proteomics of mice with total or selective modular deficits of Ranbp2. Specifically, loss of CY PPIase of Ranbp2 upregulates αA-Crystallin, which is repressed in adult nonlenticular tissues. Conversely, impairment of CY's chaperone activity opposite to the PPIase pocket downregulates a subset of αA-Crystallin's substrates, γ-crystallins. These CY-dependent effects cause age-dependent and chorioretinal-selective declines of ubiquitylated substrates without affecting the chorioretinal morphology. A model emerges whereby inhibition of Ranbp2's CY PPIase remodels crystallins' expressions, subdues molecular aging, and preordains the chorioretina to neuroprotection by augmenting the chaperone capacity and the degradation of polyubiquitylated substrates against proteostatic impairments. Further, the druggable Ranbp2 CY holds pan-therapeutic potential against proteotoxicity and neurodegeneration.

Asunto(s)

Ciclofilinas , Chaperonas Moleculares , Proteínas de Complejo Poro Nuclear , Isomerasa de Peptidilprolil , Proteostasis , Animales , Chaperonas Moleculares/metabolismo , Ratones , Ciclofilinas/metabolismo , Proteostasis/fisiología , Isomerasa de Peptidilprolil/metabolismo , Proteínas de Complejo Poro Nuclear/metabolismo , Cristalinas/metabolismo

RESUMEN

Pin1 (proline isomerase peptidyl-prolyl isomerase NIMA-interacting-1), as a member of PPIase family, catalyzes cis-trans isomerization of pThr/Ser-Pro amide bonds of its substrate proteins, further regulating cell proliferation, division, apoptosis, and transformation. Pin1 is overexpressed in various cancers and is positively correlated with tumor initiation and progression. Pin1 inhibition can effectively reduce tumor growth and cancer stem cell expansion, block metastatic spread, and restore chemosensitivity, suggesting that targeting Pin1 may be an effective strategy for cancer treatment. Considering the promising therapeutic effects of Pin1 inhibitors on cancers, we herein are intended to comprehensively summarize the reported Pin1 inhibitors, mainly highlighting their structures, biological functions and binding modes, in hope of providing a reference for the future drug discovery.

Asunto(s)

Antineoplásicos , Neoplasias , Humanos , Peptidilprolil Isomerasa de Interacción con NIMA/metabolismo , Peptidilprolil Isomerasa de Interacción con NIMA/farmacología , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Isomerasa de Peptidilprolil/química , Isomerasa de Peptidilprolil/metabolismo , Neoplasias/tratamiento farmacológico , Proliferación Celular

RESUMEN

Mammalian cells possess intrinsic mechanisms to prevent tumorigenesis upon deleterious mutations, including oncogene-induced senescence (OIS). The molecular mechanisms underlying OIS are, however, complex and remain to be fully characterized. In this study, we analyzed the changes in the nuclear proteome and phosphoproteome of human lung fibroblast IMR90 cells during the progression of OIS induced by oncogenic RASG12V activation. We found that most of the differentially regulated phosphosites during OIS contained prolyl isomerase PIN1 target motifs, suggesting PIN1 is a key regulator of several promyelocytic leukemia nuclear body proteins, specifically regulating several proteins upon oncogenic Ras activation. We showed that PIN1 knockdown promotes cell proliferation, while diminishing the senescence phenotype and hallmarks of senescence, including p21, p16, and p53 with concomitant accumulation of the protein PML and the dysregulation of promyelocytic leukemia nuclear body formation. Collectively, our data demonstrate that PIN1 plays an important role as a tumor suppressor in response to oncogenic ER:RasG12V activation.

Asunto(s)

Isomerasa de Peptidilprolil , Proteoma , Animales , Humanos , Isomerasa de Peptidilprolil/genética , Isomerasa de Peptidilprolil/metabolismo , Proteoma/metabolismo , Factores de Transcripción/metabolismo , Fibroblastos/metabolismo , Oncogenes , Peptidilprolil Isomerasa de Interacción con NIMA/genética , Peptidilprolil Isomerasa de Interacción con NIMA/metabolismo , Senescencia Celular/fisiología , Mamíferos/metabolismo

RESUMEN

The peptidyl-prolyl cis-trans isomerase Pin1 is a pivotal therapeutic target in cancers, but the regulation of Pin1 protein stability is largely unknown. High Pin1 expression is associated with SUMO1-modified protein hypersumoylation in glioma stem cells (GSCs), but the underlying mechanisms remain elusive. Here we demonstrate that Pin1 is deubiquitinated and stabilized by USP34, which promotes isomerization of the sole SUMO E2 enzyme Ubc9, leading to SUMO1-modified hypersumoylation to support GSC maintenance. Pin1 interacts with USP34, a deubiquitinase with preferential expression and oncogenic function in GSCs. Such interaction is facilitated by Plk1-mediated phosphorylation of Pin1. Disruption of USP34 or inhibition of Plk1 promotes poly-ubiquitination and degradation of Pin1. Furthermore, Pin1 isomerizes Ubc9 to upregulate Ubc9 thioester formation with SUMO1, which requires CDK1-mediated phosphorylation of Ubc9. Combined inhibition of Pin1 and CDK1 with sulfopin and RO3306 most effectively suppresses orthotopic tumor growth. Our findings provide multiple molecular targets to induce Pin1 degradation and suppress hypersumoylation for cancer treatment.

Asunto(s)

Glioma , Isomerasa de Peptidilprolil , Humanos , Peptidilprolil Isomerasa de Interacción con NIMA/genética , Peptidilprolil Isomerasa de Interacción con NIMA/metabolismo , Isomerasa de Peptidilprolil/genética , Isomerasa de Peptidilprolil/metabolismo , Sumoilación , Isomerismo , Fosforilación , Glioma/genética , Células Madre Neoplásicas/metabolismo , Proteasas Ubiquitina-Específicas/metabolismo

RESUMEN

Pin1 (protein interacting with never-in-mitosis akinase-1) is a member of the family of peptidylprolyl cis-trans isomerases (PPIases) that specifically recognize and isomerize substrates containing phosphorylated Ser/Thr-Pro sequences. Pin1 is involved in many cellular processes and plays a key role in the cell cycle, transcriptional regulation, cell metabolism, proliferation and differentiation, and its abnormalities lead to degenerative and neoplastic diseases. Pin1 is highly expressed in human cancers and promotes the development of tumors by activating multiple oncogenes and inactivating multiple tumor suppressor genes, making it an attractive target for cancer therapy. In this study, we investigated the binding mechanism and conformational relationship between benzimidazole Pin1 inhibitors and Pin1 proteins by molecular docking, three-dimensional quantitative structure-activity relationship (3D-QSAR) modeling, binding free energy calculations and decomposition, and molecular dynamics simulations. Molecular docking and molecular dynamics simulations disclosed the most likely binding pose of benzimidazoles with the Pin1 protein. The results of 3D-QSAR modeling indicated that electrostatic fields, hydrophobic fields and hydrogen bonding play important roles in the binding process of inhibitors to proteins. The binding free energy calculations and energy decomposition indicated that Lys63, Arg69, Cys113, Leu122, Met130, and Ser154 may be key residues in the binding of benzimidazole-based inhibitors to the Pin1 protein. This study provides an important theoretical basis for the design and optimization of benzimidazole compounds.

Asunto(s)

Bencimidazoles , Simulación de Dinámica Molecular , Humanos , Peptidilprolil Isomerasa de Interacción con NIMA , Simulación del Acoplamiento Molecular , Isomerasa de Peptidilprolil/química , Isomerasa de Peptidilprolil/genética , Isomerasa de Peptidilprolil/metabolismo , Unión Proteica

RESUMEN

Interbacterial antagonism and associated defensive strategies are both essential during bacterial competition. The human gut symbiont Bacteroides fragilis secretes a ubiquitin homologue (BfUbb) that is toxic to a subset of B. fragilis strains in vitro. In the present study, we demonstrate that BfUbb lyses certain B. fragilis strains by non-covalently binding and inactivating an essential peptidyl-prolyl isomerase (PPIase). BfUbb-sensitivity profiling of B. fragilis strains revealed a key tyrosine residue (Tyr119) in the PPIase and strains that encode a glutamic acid residue at Tyr119 are resistant to BfUbb. Crystal structural analysis and functional studies of BfUbb and the BfUbb-PPIase complex uncover a unique disulfide bond at the carboxy terminus of BfUbb to mediate the interaction with Tyr119 of the PPIase. In vitro coculture assays and mouse studies show that BfUbb confers a competitive advantage for encoding strains and this is further supported by human gut metagenome analyses. Our findings reveal a previously undescribed mechanism of bacterial intraspecies competition.

Asunto(s)

Infecciones Bacterianas , Microbioma Gastrointestinal , Humanos , Animales , Ratones , Bacteroides fragilis/genética , Ubiquitina/metabolismo , Bacterias/metabolismo , Isomerasa de Peptidilprolil/metabolismo

RESUMEN

Given afferent functions, sensory nerves have recently been found to exert efferent effects and directly alter organ physiology. Additionally, several studies have highlighted the indirect but crucial role of sensory nerves in the regulation of the physiological function of osteoclasts. Nonetheless, evidence regarding the direct sensory nerve efferent influence on osteoclasts is lacking. In the current study, we found that high levels of efferent signals were transported directly from the sensory nerves into osteoclasts. Furthermore, sensory hypersensitivity significantly increased osteoclastic bone resorption, and sensory neurons (SNs) directly promoted osteoclastogenesis in an in vitro coculture system. Moreover, we screened a novel neuropeptide, Cyp40, using an isobaric tag for relative and absolute quantitation (iTRAQ). We observed that Cyp40 is the efferent signal from sensory nerves, and it plays a critical role in osteoclastogenesis via the aryl hydrocarbon receptor (AhR)-Ras/Raf-p-Erk-NFATc1 pathway. These findings revealed a novel mechanism regarding the influence of sensory nerves on bone regulation, i.e., a direct promoting effect on osteoclastogenesis by the secretion of Cyp40. Therefore, inhibiting Cyp40 could serve as a strategy to improve bone quality in osteoporosis and promote bone repair after bone injury.

Asunto(s)

Resorción Ósea , Osteogénesis , Humanos , Isomerasa de Peptidilprolil/metabolismo , Osteoclastos/metabolismo , Resorción Ósea/metabolismo

RESUMEN

Gastric cancer (GC) is a malignant tumor with high incidence rate and mortality. Due to the lack of effective diagnostic indicators, most patients are diagnosed in late stage and have a poor prognosis. An increasing number of studies have proved that Peptidylprolyl isomerase A (PPIA) can play an oncogene role in various cancer types. However, the precise mechanism of PPIA in GC is still unclear. Herein, we analyzed the mRNA levels of PPIA in pan-cancer. The prognostic value of PPIA on GC was also evaluated using multiple databases. Additionally, the relationship between PPIA expression and clinical factors in GC was also examined. We further confirmed that PPIA expression was not affected by genetic alteration and DNA methylation. Moreover, the upstream regulator miRNA and lncRNA of PPIA were identified, which suggested that LINC10232/miRNA-204-5p/PPIA axis might act as a potential biological pathway in GC. Finally, this study revealed that PPIA was negatively correlated with immune checkpoint expression, immune cell biomarkers, and immune cell infiltration in GC.

Asunto(s)

MicroARNs , Isomerasa de Peptidilprolil , Neoplasias Gástricas , Humanos , Carcinogénesis/genética , Biología Computacional , MicroARNs/genética , Isomerasa de Peptidilprolil/metabolismo , Pronóstico , Neoplasias Gástricas/patología

RESUMEN

OBJECTIVES: To observe the effects of electroacupuncture (EA) on motor function, expression of extracellular cyclophile A(PPIA) and PPIA/nuclear factor-κB (NF-κB) signaling pathway in spinal cord of amyotrophic la-teral sclerosis (ALS) mice, so as to explore the mechanism of EA intervention in regulating extracellular PPIA on neuroinflammation in ALS mice. METHODS: Thirty ALS-SOD1G93A mice with hSOD1-G93A gene were randomly divided into model, EA and Riluzole groups , with 10 mice in each group, and other 10 ALS-SOD1G93A negative mice were used as the blank group. EA was applied to bilateral "Yanglingquan"(GB34) and "Zusanli"(ST36) for 20 min once daily, 5 days a week for 2 weeks. In the Riluzole group, riluzole solution (30 mg·kg-1·d-1) was administrated intragastrically, and the treatment time was the same as that in the EA group.Rotating rod experiment and open field experiment were used to evaluate the changes in motor function of mice .The morphology of motor neurons in the anterior horn of spinal cord was observed by HE staining.The relative protein expression levels of PPIA, TDP-43 and NF-κB in the spinal cord were detected by Western blot.The positive expression level of TDP-43 in the spinal cord was detected by immunohistochemistry. The positive expression level of PPIA in spinal cord was marked by immunofluorescence. Serum PPIA content was determined by ELISA. RESULTS: Compared with the blank group, the time of rod dropping and the total distance of open field movement in the model group were shortened (P<0.01), the number of motor neurons in the anterior horn of the spinal cord was reduced, the cell morphology was incomplete, the cell body was atrophied, the protein expression and positive expression of TDP-43 were increased (P<0.01), the protein expressions of PPIA and NF-κB in the spinal cord were increased(P<0.01), the serum content of PPIA and immunofluorescence expression of PPIA in spinal cord were increased (P<0.01). Compared with the model group, the time of rod dropping and the total distance of open field movement of mice in the EA group and the Riluzole group were prolonged (P<0.05, P<0.01), and the injury of motor neuron in the anterior horn of the spinal cord was decreased, the protein expression and positive expression of TDP-43 in the spinal cord were decreased (P<0.05, P<0.01)；the relative expression levels of PPIA and NF-κB proteins were decreased (P<0.05, P<0.01), and the content of PPIA in serum and the immunofluorescence expression of PPIA in the spinal cord were decreased (P<0.05, P<0.01) in the EA group；the relative protein expression of NF-κB and fluorescence expression of PPIA in spinal cord of mice in the Riluzole group were decreased (P<0.05). CONCLUSIONS: EA intervention can improve motor function in ALS mice, and its mechanism may be related to the inhibition of PPIA/NF-κB signaling pathway by EA to alleviating neuroinflammatory response.

Asunto(s)

Esclerosis Amiotrófica Lateral , Electroacupuntura , Animales , Ratones , Esclerosis Amiotrófica Lateral/genética , Esclerosis Amiotrófica Lateral/terapia , Esclerosis Amiotrófica Lateral/metabolismo , Proteínas de Unión al ADN/metabolismo , Neuronas Motoras/metabolismo , FN-kappa B/genética , FN-kappa B/metabolismo , Riluzol , Transducción de Señal , Médula Espinal , Superóxido Dismutasa-1/genética , Superóxido Dismutasa-1/metabolismo , Isomerasa de Peptidilprolil/metabolismo

RESUMEN

Legionella pneumophila is the causative agent of Legionnaires' disease, a serious form of pneumonia. Its macrophage infectivity potentiator (Mip), a member of a highly conserved family of FK506-binding proteins (FKBPs), plays a major role in the proliferation of the gram-negative bacterium in host organisms. In this work, we test our library of >1000 FKBP-focused ligands for inhibition of LpMip. The [4.3.1]-bicyclic sulfonamide turned out as a highly preferred scaffold and provided the most potent LpMip inhibitors known so far. Selected compounds were non-toxic to human cells, displayed antibacterial activity and block bacterial proliferation in cellular infection-assays as well as infectivity in human lung tissue explants. The results confirm [4.3.1]-bicyclic sulfonamides as anti-legionellal agents, although their anti-infective properties cannot be explained by inhibition of LpMip alone.

Asunto(s)

Legionella pneumophila , Legionella , Enfermedad de los Legionarios , Humanos , Enfermedad de los Legionarios/tratamiento farmacológico , Enfermedad de los Legionarios/microbiología , Proteínas de Unión a Tacrolimus , Isomerasa de Peptidilprolil/química , Isomerasa de Peptidilprolil/metabolismo , Proteínas Bacterianas/metabolismo , Legionella pneumophila/metabolismo , Legionella/metabolismo

RESUMEN

Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1) isomerizes the nearby proline (Pro) residue when it detects phosphorylated serine (Ser) or threonine (Thr) of target proteins, altering their structure, stability, function, and interaction with other proteins. Hypoxia-inducible factor 2α (HIF-2α), a transcription factor that transactivates many oncogenic genes under hypoxic conditions, harbours the pSer/Thr-Pro motif. We found for the first time that Pin1 binds to HIF-2α physically in normoxic as well as hypoxic conditions in human breast cancer cells. The level of ubiquitinated HIF-2α was significantly raised by Pin1 knockdown, while expression of its mRNA transcript was unaffected. In agreement with this observation, the cycloheximide chase assay demonstrated that Pin1 prolonged the stability of HIF-2α. Serine 672, 696, and 790 of HIF-2α were found to undergo phosphorylation. Of these, the main amino acid involved in the Pin1 binding and HIF-2α stabilization was identified as serine 790, located in the nuclear export signal region of HIF-2α. The tissue array with human breast cancer specimens showed elevated expression of HIF-2α as well as Pin1 compared to adjacent normal tissues. Knockdown of Pin1 or HIF-2α diminished breast cancer cell migration and colony formation. In conclusion, Pin1 stabilizes HIF-2α through direct interaction, which contributes to the growth of breast cancer.

Asunto(s)

Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Neoplasias de la Mama , Peptidilprolil Isomerasa de Interacción con NIMA , Femenino , Humanos , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Peptidilprolil Isomerasa de Interacción con NIMA/genética , Peptidilprolil Isomerasa de Interacción con NIMA/metabolismo , Oxígeno , Isomerasa de Peptidilprolil/genética , Isomerasa de Peptidilprolil/metabolismo , Fosforilación , Serina/genética , Serina/metabolismo

RESUMEN

Here, we demonstrate that the peptidyl-prolyl cis/trans isomerase Pin1 interacts noncovalently with the hepatitis B virus (HBV) core particle through phosphorylated serine/threonine-proline (pS/TP) motifs in the carboxyl-terminal domain (CTD) but not with particle-defective, dimer-positive mutants of HBc. This suggests that neither dimers nor monomers of HBc are Pin1-binding partners. The 162TP, 164SP, and 172SP motifs within the HBc CTD are important for the Pin1/core particle interaction. Although Pin1 dissociated from core particle upon heat treatment, it was detected as an opened-up core particle, demonstrating that Pin1 binds both to the outside and the inside of the core particle. Although the amino-terminal domain S/TP motifs of HBc are not involved in the interaction, 49SP contributes to core particle stability, and 128TP might be involved in core particle assembly, as shown by the decreased core particle level of S49A mutant through repeated freeze and thaw and low-level assembly of the T128A mutant, respectively. Overexpression of Pin1 increased core particle stability through their interactions, HBV DNA synthesis, and virion secretion without concomitant increases in HBV RNA levels, indicating that Pin1 may be involved in core particle assembly and maturation, thereby promoting the later stages of the HBV life cycle. By contrast, parvulin inhibitors and PIN1 knockdown reduced HBV replication. Since more Pin1 proteins bound to immature core particles than to mature core particles, the interaction appears to depend on the stage of virus replication. Taken together, the data suggest that physical association between Pin1 and phosphorylated core particles may induce structural alterations through isomerization by Pin1, induce dephosphorylation by unidentified host phosphatases, and promote completion of virus life cycle.

Asunto(s)

Virus de la Hepatitis B , Replicación Viral , Virus de la Hepatitis B/genética , Replicación Viral/genética , Isomerasa de Peptidilprolil/genética , Isomerasa de Peptidilprolil/metabolismo , Fosforilación