Search Results (1,005)

Fungi have evolved sophisticated mechanisms to survive in complex environments. Nematode-trapping fungi (NTF) sense and recognize nematode prey to transition from a saprophytic to predatory lifestyle, rendering them promising biocontrol agents against plant-parasitic nematodes. Ubiquitination is essential for eukaryotic cellular homeostasis, yet its regulation of NTF development and pathogenicity remains unclear. Here, we identify the conserved E3 ubiquitin ligase AoRsp5 as a critical factor for all major life stages of Arthrobotrys oligospora. Knockout of rsp5 impairs Endosomal Sorting Complex Required for Transport (ESCRT)-mediated endocytosis and compromises plasma membrane integrity. These defects trigger disturbed cellular iron homeostasis and ferroptosis-like cell death, accompanied by global dysregulation of protein phosphorylation and ubiquitination as well as prominent suppression of MAPK cascades, which further attenuate virulence-associated signaling. Overall, our findings reveal a pivotal role for Rsp5-mediated ubiquitination in coordinating cellular homeostasis and developmental transitions in NTF. Full article

CBL-B is an intracellular E3 ubiquitin ligase that acts as a T cell checkpoint by raising activation thresholds and limiting effector function. Here, genetic targeting of CBL-B enhances the performance of adoptively transferred T cells and CAR T cells under tumor microenvironment-like stress. In fully immunocompetent mouse models, Cblb deficiency or transient Cblb silencing improves control of MC-38 colon carcinoma and autochthonous mammary tumors, demonstrating that CBL-B restrains anti-tumor immunity. Cblb-deficient T cells show enhanced expansion and effector/effector-memory differentiation during an in vivo mixed lymphocyte reaction, confirming a cell-intrinsic brake function of CBL-B during sustained antigenic challenge. In a syngeneic Panc02-EpCAM model, Cblb-deficient anti-EpCAM CAR T cells show superior tumor control, enhanced infiltration, prolonged survival, and preserved effector function despite chronic antigen exposure and TGF-β. Mechanistically, Cblb targeting maintains granzyme B and IFN-γ production and is associated in vitro with increased GSDME-linked pyroptotic tumor cell death, consistent with features of immunogenic cell death. These findings extend previous CBL-B CAR T work from lymphocyte-deficient to immunocompetent settings and support CBL-B inhibition as a strategy to engineer CAR T cells that resist suppressive tumor microenvironments while promoting a more inflammatory mode of tumor killing. Full article

Panvascular diseases, characterized by systemic vascular dysfunction across multiple organ systems, represent a complex interplay of genetic susceptibility and environmental triggers. Ring Finger Protein 213 (RNF213), initially identified as the principal susceptibility gene for moyamoya disease (MMD), has emerged as a central regulator of panvascular pathophysiology. This review synthesizes current evidence elucidating RNF213′s multifaceted roles in vascular homeostasis, spanning its functions as an E3 ubiquitin ligase, mechanosensor, and immune modulator. The “second-hit” hypothesis posits that RNF213 mutations establish a genetic predisposition, while secondary insults—such as infection, hypoxia, or hemodynamic stress—precipitate pathological manifestations. Mechanistically, RNF213 orchestrates critical processes including endothelial integrity, angiogenesis, and inflammatory responses through pathways such as HIF-1α/VEGF, NF-κB, and Wnt signaling. Its dysfunction disrupts vascular remodeling, promotes aberrant smooth muscle proliferation, and exacerbates hypoxia-inflammation cycles, contributing to diverse pathologies ranging from intracranial aneurysms and arterial dissections to pulmonary hypertension and coronary artery disease. Emerging insights into RNF213′s interactions with gut microbiota, lipid metabolism, and epigenetic regulators further underscore its systemic influence. Despite advancements, unresolved questions persist regarding the context-dependent duality of RNF213 variants and organ-specific regulatory mechanisms. This review highlights the imperative for integrated approaches combining genetic, molecular, and environmental perspectives to unravel RNF213′s panvascular roles. We also outline unresolved questions regarding context-dependent effects of RNF213 variants and organ-specific regulatory mechanisms, and discuss potential avenues for future research integrating genetic, molecular, and environmental perspectives to advance understanding of RNF213′s panvascular roles. Full article

The intracellular iron levels are tightly controlled by the coordinated action of specialized proteins that regulate iron uptake, storage, and export pathways in response to iron availability. For example, Ferroportin serves as the sole mammalian iron exporter; whereas ferritin acts as the primary intracellular iron storage complex. Although both Ferroportin and ferritin are reported to be primarily degraded through lysosomal pathways, it is possible that these proteins can also be regulated through the proteasomal pathway, which may provide a more rapid mechanism to modulate intracellular iron availability. Here, we identify MDM2 as a previously unrecognized regulator of cellular iron homeostasis. We found that MDM2 is required to maintain intracellular labile iron. Mechanistically, we found that MDM2 interacts with and promotes the degradation of both Ferroportin and ferritin heavy chain. Consequently, MDM2 exerts a critical role in modulating cellular iron retention by simultaneously suppressing iron storage and iron export pathways. These findings expand the biological functions of MDM2 beyond its established role as a p53 E3 ubiquitin ligase, revealing a previously unappreciated link between MDM2 signaling and iron metabolism. Full article

The RING-type E3 ubiquitin ligase plays a significant role in plant responses and adaptations to abiotic stresses such as drought. However, few studies have explored the role of E3 ubiquitin ligases in potato drought stress, especially DRIP1. In this study, 172 StHCa genes were identified across the potato genome. These genes were unevenly distributed on twelve chromosomes and divided into six subclades (group I–VI). The molecular weight of potato HCa proteins ranges from 5445.38 to 143,293.69 Da. More than half of them are acidic proteins and most are unstable. There are 161 hydrophilic proteins, and the subcellular localization analysis indicated that they were mainly located in the nucleus. The co-linearity analysis of StHCa genes showed that 172 genes underwent 40 tandem duplications and 28 segmental duplication events. Potato and tomato share a recent common ancestor and exhibit highly similar evolutionary trajectories. Promoter sequence analysis of the StHCa family identified abundant cis-acting elements associated with light signal transduction, hormone responses, plant growth and development, and abiotic stress responses. These results suggest that the StHCa genes may play important regulatory roles in different environmental signals and developmental stages. Expression profiling revealed that StDRIP1 exhibited higher transcript levels in potato roots than in stems and leaves, and its expression was significantly induced by drought stress. Physiological phenotyping demonstrated that StDRIP1-overexpressing (OE) plants displayed reduced root growth compared with wild-type (WT) plants, with decreases in root length, total root area, total root volume, and root vitality. Under 20% PEG-6000-simulated drought stress, the root expression level of StDRIP1 was higher in OE lines than in WT plants. Furthermore, StDRIP1 overexpression suppressed the activities of antioxidant enzymes (POD, CAT, and SOD) and weakened their osmotic adjustment ability by reducing proline (Pro) accumulation. At the late stage of stress treatment (9 h), the SOD, POD, and CAT activities of OE plants were 5.0%, 19.9%, and 25.1% lower than those of WT plants, respectively. These physiological alterations exacerbated oxidative damage, as evidenced by increased malondialdehyde (MDA) content and elevated electrolyte leakage in OE plants. In summary, this study comprehensively characterized the StHCa gene family in potato, providing a valuable theoretical basis for elucidating the functional mechanism of StDRIP1 in modulating drought stress responses. Collectively, StDRIP1 acts as a negative regulator of potato drought tolerance through two primary mechanisms: (1) repressing root growth and weakening root vitality, thereby reducing the water absorption capacity of roots; and (2) diminishing antioxidant enzyme activities and impairing osmotic homeostasis, which further exacerbates oxidative damage under drought stress. Full article

Long-established prostate cancer cell lines provide limited insight into how contemporary early prostate cancer evolves into drug-resistant and neuroendocrine-like refractory disease. Patient-derived three-dimensional (3D) ex vivo models may better preserve this transition. Here, we found that 8 of 10 magnetic resonance imaging-guided biopsy specimens from patients with early-stage prostate cancer generated sustained 3D tumor spheroid cultures. After 12 weeks of enzalutamide selection, only one patient-derived culture acquired a resistant phenotype with treatment-emergent neuroendocrine prostate cancer (t-NEPC)-like features, including increased chromogranin A (CgA) and synaptophysin (SYP); reduced androgen receptor (AR), prostate-specific antigen (PSA), and prostate-specific membrane antigen (PSMA); and conversion from compact spheroids into irregular resistant aggregates. During this transition, WD repeat and SOCS box-containing protein 1 (WSB1) increased, whereas PSMA progressively decreased. WSB1 silencing restored PSMA, AR, and PSA expression and reduced neuroendocrine-associated features. A similar WSB1 dependency was observed in enzalutamide-resistant LNCaP cells, the castration-resistant prostate cancer model 22Rv1, and the neuroendocrine/small-cell prostate cancer model NCI-H660. Mechanistically, WSB1 functioned as a SOCS box-dependent E3 ubiquitin ligase adaptor that promoted PSMA ubiquitination and degradation. SOCS box deletion or T380A mutation impaired this process, while Aurora kinase A (AURKA) inhibition reduced WSB1-dependent PSMA ubiquitination. WSB1 depletion, AURKA inhibition with alisertib, and combined AURKA inhibition with EZH2 suppression reduced resistant aggregate growth and increased apoptosis-associated markers in patient-derived enzalutamide-resistant neuroendocrine-like spheroids and related models. These findings nominate the AURKA–WSB1–PSMA axis as a therapeutic vulnerability in refractory prostate cancer. Full article

Influenza A virus (IAV) remains a major threat to global public health because of its capacity for antigenic drift, reassortment, zoonotic transmission, and pandemic emergence. Viral transcription and genome replication are carried out by the influenza virus RNA-dependent RNA polymerase (FluPol), a heterotrimeric complex composed of polymerase basic protein 1 (PB1), polymerase basic protein 2 (PB2), and polymerase acidic protein (PA), which functions together with nucleoprotein (NP) within viral ribonucleoprotein complexes (vRNPs). FluPol activity is regulated not only by viral determinants and host cofactors but also by diverse post-translational modifications. Among these, ubiquitination has emerged as a particularly versatile regulatory mechanism because it can control protein stability, polymerase assembly, subunit interactions, conformational dynamics, NP–RNA interactions, and innate immune signaling. Depending on the modified substrate, ubiquitin linkage type, acceptor residue, and responsible E3 ligase or deubiquitinase, ubiquitination may either restrict IAV replication or be exploited by the virus to enhance polymerase function and vRNP activity. This review summarizes recent advances in ubiquitination-mediated regulation of FluPol and NP, focusing on the responsible E3 ubiquitin ligases, deubiquitinases, ubiquitination sites, ubiquitin-chain types, and host restriction mechanisms. We further discuss the crosstalk between ubiquitination and other post-translational modifications, highlight unresolved mechanistic questions, and evaluate the therapeutic potential and challenges of targeting ubiquitin-dependent pathways for antiviral intervention. Collectively, this review provides a conceptual framework for understanding how ubiquitination shapes IAV replication and identifies E3 ligases and DUBs as potential targets for host-directed antiviral strategies. Full article

Background/Objectives: Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental condition characterized by a complex and multifactorial genetic architecture. In this study, we report a male patient, born to non-consanguineous healthy parents, presenting with ADHD and oppositional defiant disorder (ODD). Methods: Trio-based whole-exome sequencing (WES) was performed in the proband and both parents. Variant classification was performed according to American College of Medical Genetics and Genomics (ACMG) guidelines, and the potential pathogenicity of the identified variant was further assessed through multiple in silico prediction algorithms and protein structural analyses. Results: WES identified a homozygous variant in the LNX2 gene (NM_153371.4: c.1165G>A, p.Ala389Thr), classified as a variant of uncertain significance (VUS) and supported by multiple in silico predictions. LNX2 is expressed during brain development and encodes an E3 ubiquitin ligase involved in neuronal differentiation and synaptic function. The identified variant is located within the PDZ2 domain, a functionally relevant region involved in protein–protein interactions. Although the variant is reported in population databases (gnomAD ID: rs148429804), it has not been associated with any clinical phenotype, and its presence in the homozygous state has been reported only once, remaining extremely rare and lacking clinical annotation. Structural modelling predicted localized rearrangement of the hydrogen-bonding network within the PDZ2 domain without major conformational changes. Integrative transcriptomic, and single-cell analyses further supported the biological relevance of LNX2 in neurodevelopment, highlighting its preferential association with neuronal projection-cell networks, synaptic vesicle trafficking pathways, and neuron-specific regulatory programs. Conclusion: Although the identified LNX2 variant cannot be considered causative for the patient’s phenotype and a definitive disease–gene relationship cannot be established based on a single individual, the complementary genetic, structural, and transcriptomic findings support the biological plausibility of LNX2 as a candidate gene for neurodevelopmental disorders. Additional independent patients and functional studies will be required to clarify its contribution to human disease. Full article

Targeted Protein Degradation (TPD) has emerged as a transformative paradigm in drug discovery, offering a robust strategy to address “undruggable” targets. This study presents the first 25-year longitudinal scientometric analysis (2001–2025) of the TPD field, integrating data from 2750 publications across the Web of Science Core Collection, Scopus, and PubMed to map the global research landscape and therapeutic innovations. The results indicate that TPD research entered an explosive growth phase post-2016. China leads in publication volume (1247 papers), while the USA maintains dominance in citation impact (H-index = 80) and foundational leadership. The Chinese Academy of Sciences and Harvard University were identified as core institutions, with Craig M. Crews confirmed as a pivotal scholar. Thematic analysis reveals a systematic evolution from foundational ubiquitin-proteasome mechanisms to the clinical translation of advanced modalities, including Proteolysis-Targeting Chimeras (PROTACs), molecular glues, and non-ubiquitin-dependent platforms like LYTACs and AUTACs. Clinical viability is evidenced by the FDA approval of the agent ARV-471 for oncology. Despite this progress, critical challenges remain regarding E3 ligase expansion, molecular design optimization, and off-target toxicity. This review provides a data-driven roadmap for future TPD development, bridging the gap between academic output and real-world translational science to guide researchers, clinicians, and industry partners in navigating this dynamic therapeutic frontier. Full article

The ubiquitin ligase protein tripartite-motif containing 56 (TRIM56) positively regulates Toll-like receptor-3 (TLR3) signaling by forming a complex with Toll-Interleukin-1 receptor domain-containing adapter protein inducing interferon (IFN)-beta (TRIF), independent of its E3 ligase activity. Whether TRIM56 modulates other TLR pathways in innate antiviral immunity, however, is unclear. Herein, we show ectopic expression of TRIM56 augments activation of IFN regulatory factor-3 (IRF3)-dependent promoters following stimulation by lipopolysaccharide (LPS) in HEK293-TLR4-MD2-CD14 cells while leaving activation of NF-κB-dependent promoter unaffected, suggesting TRIM56 specifically promotes immune signaling through the TLR4-TRIF axis but not the MYD88 arm downstream of this TLR. Confirming its impact on endogenous antiviral responses in immune sentinel cells naturally harboring the TLR4 pathway, we demonstrated enforced expression of TRIM56 enhanced LPS-induced expression of IFN-beta and IFN-stimulated genes (ISGs) and establishment of an antiviral state in bone marrow-derived macrophages. Importantly, depletion of endogenous TRIM56 impaired LPS-induced antiviral gene expression and cellular antiviral defense. Altogether, these data add to understanding of the role of TRIM56 in TLR-mediated innate immune responses. Given that TRIM56 is an ISG and that many immune adjuvants and some viral proteins activate TLR4, the findings of this study could have implications for designing immunotherapies, especially those against viral infections. Full article

The human APOBEC3 (A3) family of cytidine deaminases, including A3G, A3F, and A3H, participates in cellular anti-retroviral immunity. In contrast, to antagonize the anti-retroviral activities of these A3 family proteins, HIV-1 produces its gene product called viral infectivity factor (Vif) in infected cells. Vif is a pleiotropic hub protein that specifically binds to various A3 proteins with the aid of host core-binding factor subunit β (CBF-β) and mediates their proteasomal degradation. To date, numerous biological and structural studies have been performed to understand the arms race between A3 and Vif. Previous extensive mutagenesis and structural analyses have suggested that there are three distinct types of Vif-binding interfaces among human A3s and three largely nonoverlapping interfaces on Vif for binding with these A3s. Moreover, recent cryo-electron microscopy (cryo-EM) structural analyses have clarified further details of the different intermolecular interactions of Vif with each of three human A3s (A3G, A3F, and A3H) and have proposed a possible mechanism by which one Vif molecule can recognize all three types of A3s. In this review, we summarize the current understanding of the structural basis of the interaction between A3 and Vif. This information may be helpful for developing drugs targeting these interfaces. Full article

Proteasome inhibitors are approved to treat multiple myeloma and mantle cell lymphoma. Recent reports suggest sarcomas also display proteasome addiction. Mechanistic explanations cite proteotoxic stress. In sarcoma patients, we analyzed the impacts of 377 human E3 ubiquitin ligases on sarcoma patient overall survival (OS) and recurrence-free survival (RFS), identified substrates of E3 ligases with the most significant and robust effects, and performed enrichment analyses. High expression of 102 E3 ligases was associated with shortened OS. Thirteen of these shortened OS by >40 months, six with false-discovery rates (FDR) ≤ 5%. Nineteen showed correlation between increased expression and shortened RFS, two with FDR ≤ 5%. Overexpression of 73 E3 ligases significantly extended OS, with 18 extending OS by >40 months; six with FDR ≤ 5%. Elevated expression of 21 significantly extended RFS, one with FDR ≤ 5%. Enrichment analyses of substrates unique to the E3 ligases whose elevated expression most reliably shortened or extended OS by >40 months revealed non-overlapping functions: the E3 ligases associated with shortened OS uniquely targeted cell cycle, cell–cell communication, cellular responses to stimuli, chromatin organization, DNA repair, DNA replication, hemostasis, reproduction, and vesicle-mediated transport functions. Both OS-impacting E3 ligase sets targeted developmental biology, gene expression, immune system, metabolism of proteins, and signal transduction functions. Three specific functions were targeted by both groups. Functions uniquely targeted by each set of ligases could reveal therapeutic targets with a greater therapeutic index than the proteasome. Full article

Hepatitis B virus (HBV) infection remains a major global health burden, with chronic infection leading to severe liver diseases including cirrhosis and hepatocellular carcinoma (HCC). HBV-encoded X protein (HBx) plays a critical role in viral replication and pathogenesis by modulating host cellular processes, including autophagy and lysosomal function. However, the molecular mechanisms by which HBx disrupts lysosomal biogenesis and autophagic degradation remain elusive. In this study, we show that HBx downregulates the transcription factor EB (TFEB), a master regulator of lysosomal biogenesis, which leading to impaired lysosomal acidification and autophagosome–lysosome fusion. Mechanistically, HBx-mediated TFEB downregulation involves the CUL4A (Cullin 4A)/CUL4B (Cullin 4B)-DDB1 (DNA damage-binding protein 1) E3 ubiquitin ligase complex and is dependent on the DDB1-interacting motif in HBx. HBx mutants defective in DDB1 binding (HBx^R96E and HBx^ΔDBD) fail to downregulate TFEB or impair lysosomal function. Collectively, our findings identify a pathway by which HBx disrupts lysosomal function via CUL4A/CUL4B–DDB1-dependent TFEB downregulation, providing insights into HBV-associated liver pathogenesis and highlighting potential targets for therapeutic intervention. Full article

Ubiquitination is a post-translational modification that governs various facets of eukaryotic biology, including protein stability, signaling, and immune regulation. The modification process is mediated by a coordinated enzymatic cascade, in which E3 ubiquitin ligases confer substrate specificity and determine the functional outcome of ubiquitin attachment. In the case of a virus infection, host cellular signaling networks undergo major ubiquitin-dependent changes to protect the host cell, including remodeling of cellular organelles, coordination of innate immunity, and reprogramming of metabolic pathways to prevent virus replication. African swine fever virus (ASFV) has evolved numerous strategies to counteract or evade these responses, thereby manipulating host defenses and promoting its replication. By modulating ubiquitination-dependent host cellular functions, the virus can regulate key immune signaling factors, suppress interferon production, and interfere with inflammatory pathways. These actions not only antagonize antiviral defenses but also remodel cellular homeostasis to favor infection. The important interplay between host defense and viral manipulation underscores the versatility of the ubiquitin system as a battleground in ASFV infection. In this review, we discussed mechanistic insights into how ASFV subverts ubiquitin pathways during host–virus interactions. This comprehensive knowledge might be beneficial for pharmaceutical exploration of host E3 ligase-dependent anti-ASFV treatment. Full article

Background: Although ERα-positive breast cancer represents approximately 70% of all breast cancer diagnoses worldwide, specific prognostic biomarkers for this subtype that are capable of stratifying patients remain limited. TRIM28 (KAP1/TIF1β), which is a multifunctional E3 ubiquitin ligase and transcriptional coregulator of ERα, has been shown to play oncogenic roles in multiple malignancies. However, its prognostic significance in ERα-positive breast cancer subtype has not been explored across independent patient cohorts. Methods: Multiple bioinformatics tools were employed to assess TRIM28 mRNA expression and prognostic significance across independent patient cohorts totaling over 4000 patients. The Kaplan–Meier plotter was used to examine associations between TRIM28 expression and survival outcomes in ERα-positive breast cancer. Multivariate Cox proportional hazards regression was performed in the METABRIC dataset (n = 1356) to confirm independent prognostic value, with sensitivity analyses using alternative TRIM28 expression cutoffs and PAM50 subtype-specific subgroup analyses. Independent validation was performed using multivariate Cox regression in the TCGA-BRCA Firehose Legacy ERα-positive cohort (n = 372). Gene Set Cancer Analysis (GSCA) was used to investigate pathways associated with TRIM28-correlated genes, and Breast Cancer Gene-Expression Miner (Bc-GenExminer) was used to assess immune cell infiltration. Results: TRIM28 expression is significantly elevated in ERα-positive breast cancer compared to normal breast tissue. High TRIM28 expression (defined as the upper quartile, ≥75th percentile, of TRIM28 expression) is independently associated with worse overall survival after adjustment for tumour size, tumour mutational burden (TMB), hormone therapy status, and age, with stratification on histologic grade (HR = 1.21, 95% CI: 1.03–1.41, p = 0.0194; METABRIC, n = 1356). This finding was independently validated using multivariate Cox proportional hazards regression in the TCGA-BRCA Firehose Legacy ERα-positive cohort (n = 372; events = 56), in which high TRIM28 expression remained independently associated with worse OS after adjustment for age, T-stage, and TMB (HR = 2.02, 95% CI: 1.10–3.71, p = 0.024). PAM50 subtype-specific analyses within METABRIC additionally confirmed an independent association of high TRIM28 with worse OS in Luminal A (HR = 1.37, 95% CI: 1.08–1.74, p = 0.009), with a directionally consistent but non-significant trend in Luminal B (HR = 1.21, 95% CI: 0.93–1.58, p = 0.155). The prognostic effect was robust across alternative TRIM28 expression cutoffs. TRIM28 expression positively correlates with tumour size, histologic grade, Nottingham Prognostic Index, and TMB, and negatively correlates with immune cell infiltration and is significantly lower in patients receiving hormone therapy. Genes co-expressed with TRIM28 are enriched in cell cycle and DNA damage response activation signatures and RAS/MAPK and RTK pathway inhibition signatures. Conclusions: TRIM28 is an independent prognostic biomarker in ERα-positive breast cancer, validated across multiple independent cohorts. These findings nominate TRIM28 as a priority candidate for prospective clinical validation and targeted experimental investigation in ERα-positive breast cancer. Full article