The t(10;11)(p13;q14-21) PICALM::MLLT10 chromosomal translocation results in the production of the CALM-AF10 fusion oncoprotein and is a driver mutation in both acute myeloid and T-lymphoblastic leukemia. PICALM::MLLT10 translocated leukemia is primarily an epigenetically driven disease. Global hypomethylation results in genomic instability, while focal H3K79 hypermethylation at target genes induces cell proliferation and blocks differentiation. Nucleocytoplasmic shuttling of CALM-AF10 and its protein partners and impaired endocytosis at the plasma membrane further influence the leukemic phenotype. Leukemias characterized by PICALM::MLLT10 have historically been recognized to portend a poor prognosis; however, insights from larger patient cohorts provide refinement to the prognostic relevance of this chromosomal translocation, highlighting chemotherapy resistance in this leukemic subtype. In addition, a deeper biological understanding of the disease hints at potential therapeutic targets. This approach is demonstrated in the recent promising results achieved utilizing venetoclax, a BCL2 inhibitor, in patients with PICALM::MLLT10 acute leukemia. Herein, we provide updates on the pathophysiology, clinical presentation, prognosis, and treatment of PICALM::MLLT10 acute leukemia.

FOXOs constitute a class of evolutionarily conserved transcription factors that play pivotal roles in diverse cellular processes, including glucose and lipid metabolism, energy homeostasis, oxidative stress response, and autophagy. They are recognized as central regulators of longevity. This review details the mechanisms linking FOXO to aging. FOXO activity is regulated via nucleocytoplasmic shuttling, a process controlled by phosphorylation and dephosphorylation through the insulin/insulin-like growth factor (IIS) signaling pathway. This shuttling influences the expression of aging-related genes, thereby modulating aging-related phenotypes in tissues such as muscle and liver. Furthermore, FOXO can also regulate the autophagy pathway through multiple mechanisms: On one hand, it transcriptionally activates core autophagy genes such as Ulk2 and Becn1; on the other hand, it enhances autophagic activity by modulating miRNAs or epigenetic modifications, thereby promoting the elimination of damaged cellular components, and ultimately delaying organismal aging. Moreover, as a key sensor of oxidative stress, FOXO is activated by reactive oxygen species (ROS), thereby inducing the expression of antioxidant enzymes that mitigate oxidative damage and delay cellular aging. This review provides an in-depth exploration of the dual roles of FOXO in various aging-related diseases. This includes neurodegenerative diseases (such as Huntington's disease, Parkinson's disease, and Alzheimer's disease), metabolic disorders (such as type 2 diabetes), and various cancers. Meanwhile, this review also discusses drugs targeting the FOXO pathway in recent years (such as canagliflozin, metformin, resveratrol, and berberine). These FOXO-targeting compounds demonstrate great potential in improving metabolic disorders and delaying the onset of aging phenotypes.

In silico characterization of the OSBPL6 gene and its potential role in ascites syndrome in broiler chickens.

Skin repair after injury is a complex multistage process. Reepithelialization is a vital component of skin wound healing and involves intricate molecular regulations that are still not fully understood. Here, using a combination of human tissue and animal models, we identified histone deacetylase 5 (HDAC5) as a key mediator of reepithelialization through a mechanism involving nucleocytoplasmic shuttling to regulate deacetylation of a nonhistone protein. We conducted functional validation through a conditional gene knockout mouse model. In addition, parallel studies using ex vivo human skin confirmed that HDAC5 cytoplasmic localization is necessary for efficient wound closure. Liquid chromatography-mass spectrometry of mouse wounds revealed that cytoplasmic HDAC5 interacts with alpha-actinin-4 (ACTN4). Site-directed mutagenesis, immunofluorescence, and luciferase assays demonstrated that HDAC5 deacetylates ACTN4 at the K417 site, allowing nuclear translocation of ACTN4 and subsequent modulation of transcriptional activity of Y-box-binding protein 1 (YBX1). Single-cell transcriptome analysis of mouse wounds revealed cystatin A as a key factor downstream of the HDAC5/ACTN4/YBX1 axis that enhanced reepithelialization and wound healing. We further identified an HDAC5-selective activator, G194-0712, and showed that it improved wound healing in three mouse models of chronic wounds: diabetic wounds, ischemic wounds, and radiation injury. Together, these results highlight a previously unappreciated mechanism involved in skin repair and suggest that HDAC5 activation may hold promise for the treatment of nonhealing skin wounds.

Nucleocytoplasmic shuttling of sirtuin 1 regulates histone modifications and transcriptional events during early porcine embryonic development.

Disrupting the PA2G4-NPM1 axis induces nucleolar stress in NPM1c AML

Nuclear trafficking of PDK1 in importin7-dependent manner is required for insulin-induced AKT ubiquitination.

Histone deacetylase 4 (HDAC4) modifies both histone and non-histone proteins, but its role in the transition from acute kidney injury (AKI) to chronic kidney disease (CKD) remains unclear. Here, we investigated the function and mechanism of HDAC4 in ischemia–reperfusion (IR)–induced AKI–CKD progression using Tasquinimod, a highly selective HDAC4 inhibitor, and conditional tubular HDAC4 knockout mice. We found that HDAC4 expression was persistently upregulated after IR and was associated with sustained ferroptosis. Both pharmacological inhibition and tubular deletion of HDAC4 suppressed ferroptosis, alleviated tubular injury, and reduced fibrosis. Mechanistically, HDAC4 promoted ferroptosis by regulating the nucleocytoplasmic shuttling of Foxo3a: it enhanced Foxo3a phosphorylation, bound Foxo3a in the cytoplasm, and induced its deacetylation, collectively sequestering Foxo3a in the cytoplasm and reducing GPX4 transcription. Inhibition or deletion of HDAC4 restored Foxo3a nuclear localization, upregulated GPX4, and decreased lipid peroxidation. These findings identify HDAC4 as a key mediator linking IR injury to ferroptosis and fibrotic progression, suggesting that targeting the HDAC4–Foxo3a axis may provide a novel therapeutic strategy to prevent the AKI–CKD transition.

Neointimal hyperplasia is the major cause of significant vascular complications after arterial interventions. Despite the advancements in strategies such as drug-eluting stents to minimize neointimal hyperplasia, achieving consistently effective long-term outcomes remains a challenge. Protein-protein interactions mediated by PDZ (PSD-95, Discs-large, and ZO-1) domains are essential for numerous biological processes. However, little is known about the role of PDZ proteins in neointima formation. This study aims to explore the role of TAX1BP3 (Tax1 binding protein 3), a singular PDZ protein, in phenotypic switching of vascular smooth muscle cells (VSMCs) and its implication in neointimal hyperplasia. Subcellular localization of TAX1BP3 was assessed in isolated VSMCs or arteries obtained from mice with neointima formation. TAX1BP3 mutants were constructed to study the role of SUMOylation on TAX1BP3 nucleocytoplasmic shuttling. VSMC-specific Tax1bp3 knockout mice were generated to determine the relevant phenotypes in a carotid artery wire injury model. RNA sequencing, assays for transposase-accessible chromatin using sequencing, computational prediction of complex structures, and coimmunoprecipitation were performed to elucidate the underlying molecular mechanisms. Adeno-associated virus-mediated Tax1bp3 gene delivery and nanoencapsulated-TAX1BP3 were employed to investigate the potential translational relevance. TAX1BP3 exhibited dynamic nucleocytoplasmic shuttling during phenotypic switching of VSMCs. TAX1BP3 is SUMOylated at K116, and its SUMOylation is essential for maintaining the nuclear localization of TAX1BP3. Deficiency of TAX1BP3 facilitated the transition from a contractile to a synthetic phenotype and aggravated neointima formation after vascular injury in mice. The integration of RNA sequencing and an assay for transposase-accessible chromatin using sequencing unveiled that TAX1BP3 primarily regulated the cell cycle progression and cell proliferation of VSMCs through YAP-TEAD transcription activity. The computational prediction of TAX1BP3/YAP1 complex structures and protein interaction-related experiments revealed that TAX1BP3 and TEAD1 compete for binding to YAP through its TEAD binding domain (BD) in a noncanonical PDZ manner. AAV-mediated Tax1bp3 gene delivery significantly attenuated postinjury neointima formation and the progression of atherosclerosis. Nanoencapsulated-TAX1BP3 administration effectively reduced VSMC phenotypic switching and neointimal hyperplasia. These results demonstrate that SUMOylation of TAX1BP3 at K116 enables its nucleocytoplasmic shuttling during phenotypic switching of VSMCs. TAX1BP3 competitively interacts with the YAP-TEAD complex in a noncanonical PDZ manner and exerts its protective role in vascular neointimal hyperplasia primarily through the regulation of cell proliferation.

Histone deacetylase four (HDAC4) undergoes dynamic nucleocytoplasmic shuttling, a process critical for regulating its activity. However, aberrant nuclear accumulation of HDAC4 is associated with both neurodevelopmental and neurodegenerative disease, and in our Drosophila model, impairs normal neuronal development. Upon nuclear accumulation, HDAC4 forms biomolecular condensates, previously termed aggregates, that correlate with the severity of defects in development of the Drosophila mushroom body and adult eye. Here we determined that nuclear condensation of HDAC4 is dependent on self-oligomerization, and that impairing oligomerization reduces condensation and the severity of neurodevelopmental phenotypes in Drosophila. HDAC4 condensates are highly dynamic and are stabilized by the presence of MEF2, which promotes their formation, ultimately exacerbating phenotypic severity. These data provide insight into the role of HDAC4 condensates in normal neuronal function and suggest that their dysregulation may contribute to neurodevelopmental disorders. Consequently, targeting oligomerization of HDAC4 and its interaction with MEF2 present potential therapeutic strategies for diseases associated with HDAC4 nuclear accumulation.

RNA trafficking is crucial in almost every phase of plant development. Fibrillarin (FIB), a highly conserved nucleolar protein with methyltransferase (MTase) activity, functions in methylation and rRNA processing and facilitates the transport of several RNA viruses in plants. Previously, we demonstrated that bamboo mosaic virus satellite RNA (satBaMV) traffics autonomously and systemically in a helper virus-independent but FIB-dependent manner by forming a mobile ribonucleoprotein (RNP) complex comprising satBaMV, FIB, and satBaMV-encoded P20 movement protein. Here, we show that FIB methylates the arginine-rich motif (ARM) of P20 and relies on its MTase activity for the systemic movement of satBaMV. FIB MTase-defective mutants failed to complement long-distance satBaMV transport in FIBi plants, despite still binding to satBaMV in vivo. We also demonstrate that the ARM of P20 guides its nucleolar localization for FIB-mediated methylation. P20 methylation not only contributes to its plasmodesmata (PD) targeting but also triggers nucleocytoplasmic shuttling of FIB with P20 as the RNP complex to PD. A satBaMV mutant harboring a nonmethylated P20, but not a methylation-mimic P20, exhibited disrupted PD targeting and impaired P20-assisted satBaMV trafficking. Our findings provide mechanistic insights into how FIB-mediated P20 methylation positively regulates systemic trafficking of a subviral agent in plants.

ABSTRACTMicroglia, the brain's resident immune cells, are crucial for maintaining healthy brain homeostasis. However, as the brain ages, microglia can shift from a neuroprotective to a neurotoxic phenotype, contributing to chronic inflammation and promoting neurodegenerative processes. Despite the importance of understanding microglial aging, there are currently few human in vitro models to study these processes. To address this gap, we have developed a model in which human microglia undergo accelerated aging through inducible progerin expression. HMC3‐Progerin cells display key age‐related markers such as activation of the senescence‐associated secretory phenotype (SASP) as well as an increase in DNA damage. These prematurely aged HMC3 cells show a reduced response to LPS activation, exhibit impairments in essential microglial functions including decreased migration and phagocytosis as well as transcriptomic alterations including a shift observed in aging and neurodegeneration. Additionally, we observed an impaired stress response and a defect in nucleocytoplasmic transport, especially affecting the amyotrophic lateral sclerosis (ALS) associated protein FUS. This suggests that microglia play a contributory role in driving neurodegenerative processes in the aging brain. Our microglia aging model offers a valuable tool for exploring how aged microglia affect brain function, enhancing our understanding of their role in brain aging.

Myosin inhibition enhances cardiomyocyte cell cycle activity through SIRT1-NFAT-mediated H3K9me3 modification.

N4BP1 is a nucleocytoplasmic shuttling protein and recognizes aggregates of the ubiquitin-like protein NEDD8 to protect cells under heat shock.

Nuclear factor kappa B (NF-κB) has been extensively investigated for approximately four decades. Throughout this timeframe, significant progress has been accomplished in determining the structure, function, and regulation of NF-κB; however, some nuanced complexities of this fundamental signaling pathway remain underexplored. A notable gap exists in the spatiotemporal regulation and molecular dynamics of NF-κB nucleocytoplasmic shuttling, which significantly impacts the complex function and behavior, yet lacks comprehensive characterization. The nucleocytoplasmic shuttling process is also related to resistance mechanisms that evolved following the application of NF-κB or proteasomal inhibitors. Furthermore, the NF-κB complex has a stochastic variability in its trafficking that contributes to heterogeneous cellular responses at the single-cell level and lacks a well-defined druggable pocket, making its complete suppression in cancer cells challenging and uncertain. Engineering synthetic gene circuits and utilizing optogenetic tools can pave the way for precise control of the NF-κB complex, enabling advanced investigations into NF-κB regulation and post-therapeutic behavior implicated in cancer resistance. This approach also permits tumor microenvironment (TME)-immune modulation by synthetic gene circuits that reactivate immune cells within the TME. In this review, we discussed the structure and function of NF-κB, the molecular dynamics of NF-κB nucleocytoplasmic shuttling based on established findings, NF-κB engineering via synthetic biology tools, and critically deciphered the post-therapeutic behavior of NF-κB in cancer, supported by potential therapeutic targets to abrogate resistance.

Unraveling viral protein-host membrane interaction for dengue and Zika.

Cytoplasmic mislocalisation and nuclear depletion of TDP-43 are pathological hallmarks of amyotrophic lateral sclerosis (ALS), including mutations in the C9ORF72 gene that characterise the most common genetic form of ALS (C9ALS). Studies in human cells and animal models have associated cytoplasmic mislocalisation of TDP-43 with abnormalities in nuclear transport receptors, referred to as karyopherins, that mediate the nucleocytoplasmic shuttling of TDP-43. Yet the relationship between karyopherin abnormalities and TDP-43 pathology are unclear. Here we report karyopherin-α4 (KPNA4) pathology in the spinal cord of TDP-43-positive sporadic ALS and C9ALS patients. Structural analyses revealed the selective interaction between KPNA subtypes, especially KPNA4, with the nuclear localisation signal (NLS) of TDP-43. Targeted cytoplasmic mislocalisation and nuclear depletion of TDP-43 caused KPNA4 pathology in human cells. Similar phenotypes were observed in Drosophila whereby cytoplasmic accumulation of the TDP-43 homolog, TBPH, caused the nuclear decrease and cytosolic mislocalisation of the KPNA4 homolog, Importin-α3 (Impα3). In contrast, induced accumulation of Impα3 was not sufficient to cause TBPH mislocalisation. Instead, targeted gain of Impα3 in the presence of accumulating cytosolic TBPH, restored Impα3 localisation and partially rescued nuclear TBPH. These results demonstrate that cytoplasmic accumulation of TDP-43 causes karyopherin pathology that characterises ALS spinal cord. Together with earlier reports, our findings establish KPNA4 abnormalities as a molecular signature of TDP-43 proteinopathies and identify it as a potential therapeutic target to sustain nuclear TDP-43 essential for cellular homeostasis affected in ALS and frontotemporal dementia.

SUMOylation is a critical post‑translational modification, serving as a key role in nucleocytoplasmic translocation, transcriptional cofactor stabilization and modulation of chromatin remodeling factors, which are associated with oncogenesis, tumor progression and chemotherapy resistance in various types of cancer. SUMOylation was performed by small ubiquitin‑like modifier (SUMO), a kind of small ubiquitin‑like modifier, which was attached or removed from the substrates. The excessive export of nuclear p27kip1 induced by SUMOylation is associated with cell proliferation and chemotherapy resistance in cholangiocarcinoma (CCA). However, the exact underlying mechanism remains currently unknown. The present study investigated SUMO specific peptidase 1 (SENP1), which is known to participate in SUMOylation by activating nuclear SUMO1 precursors and deSUMOylating cytoplasmic substrates. SENP1 exhibited increased expression levels in CCA specimens compared with that in adjacent non‑cancerous tissues, as confirmed by bioinformatics analysis and immunohistochemical assays. A significant correlation between SENP1 and p27kip1 expression levels was observed. SENP1 overexpression significantly increased cytoplasmic p27kip1 expression levels, thereby promoting CCA cell proliferation, accelerating the G1‑S cell cycle transition and reducing chemical sensitivity through increasing overall SUMOylation of p27kip1, as confirmed via western blotting, immunofluorescence, flow cytometry, Cell Counting Kit‑8, 5‑ethynyl‑2'‑deoxyuridine incorporation and SUMOylation tests. By contrast, SENP1 knockdown demonstrated the opposite results. Subsequently, the use of ML‑792, COH000 and leptomycin B treatments, and the mutant variant SENP1‑C603A demonstrated that SENP1 regulates the functionality of p27kip1 through nuclear SUMOylation rather than cytoplasmic deSUMOylation. The involvement of SENP1 represents a pivotal role in governing the nucleocytoplasmic shuttling of p27kip1. SENP1 knockdown could effectively impede CCA cell proliferation and enhance the chemosensitivity of cis‑platinum by modulating the nuclear export of p27kip1 through SUMOylation, thus offering a potential therapeutic approach for CCA in the future.

Thyroid carcinogenesis has multiple hallmarks, including evasion of tumor suppressors. Reactivation of wild-type p53 function is the ultimate goal in cancer therapy, which requires an understanding of the p53 suppression mechanism specific to the cancer type. MiR-7-5p and IPO7 are implicated in the pathogenesis of several human diseases. This work aims to investigate the role of miR-7-5p and IPO7 in p53 regulation in papillary thyroid cancer (PTC) cells. Primary cultured thyroid cells and FFPE thyroid tissues from PTC and benign cases were used. Functional experiments were performed by transfection with IPO7 siRNA or miR-7-5p mimic/inhibitor, followed by apoptosis and luciferase reporter assays, immunoblot assays, and RT-PCR. The expression and subcellular localization of IPO7, p53, MDM2, and ribosomal proteins (RPL11 and RPL5) were studied by immunofluorescence staining and confocal microscopy. The results show that IPO7 is overexpressed in PTC and regulated by miR-7-5p. Modulation of IPO7 expression in cultured thyroid cells altered the nucleocytoplasmic shuttling of p53, MDM2, RPL11, and RPL5, in addition to the p53 protein level and activity. The expression pattern of IPO7, p53, and MDM2 in cultured thyroid cells and clinical thyroid tissue specimens confirmed the association between IPO7 overexpression and reduced p53 stability in PTC. In conclusion, the data here show that p53 level and activity are differentially controlled in malignant and benign thyroid cells through miR-7-5P/IPO7-mediated regulation of RP-MDM2-p53 nucleocytoplasmic trafficking. In PTC, downregulation of miR-7-5p with consequent overexpression of IPO7 might be a protective mechanism used by cancer cells to evade p53 growth suppression during carcinogenesis.

SummaryThe NF-κB/IκBα pathway regulates key cellular processes, including development, immunity, and inflammation. In Drosophila, the homologous Dorsal/Cactus system patterns the dorsoventral axis of the blastoderm embryo. While the inhibitor Cactus has been suggested to play multiple roles in regulating Dorsal, direct visualization of Cactus is challenging due to its rapid turnover. To overcome this challenge, we endogenously tagged Cactus with a nanobody against GFP and quantitatively imaged Cactus distribution in live embryos. We found that, like Dorsal, Cactus undergoes nuclear-cycle driven dynamics and nucleocytoplasmic shuttling. Using a mathematical model constrained by our data, we estimated Cactus nuclear and cytoplasmic concentration. Our results imply that the Dorsal gradient has increased spatial range, robustness, and precision due to the presence of Cactus in the nucleus uniformly throughout the embryo. This study provides insights into NF-κB regulation in Drosophila embryos and highlights the need for similar quantitative studies in other biological systems.