Small Ubiquitin-like Modifier Research Articles

Highly sensitive site-specific SUMOylation proteomics in Arabidopsis.

SUMOylation-the attachment of a small ubiquitin-like modifier (SUMO) to target proteins-plays roles in controlling plant growth, nutrient signalling and stress responses. SUMOylation studies in plants are scarce because identifying SUMOylated proteins and their sites is challenging. To date, only around 80 SUMOylation sites have been identified. Here we introduce lysine-null SUMO1 into the Arabidopsis sumo1 sumo2 mutant and establish a two-step lysine-null SUMO enrichment method. We identified a site-specific SUMOylome comprising over 2,200 SUMOylation sites from 1,300 putative acceptors that function in numerous nuclear processes. SUMOylation marks occur on several motifs, differing from the canonical ψKxE motif in distant eukaryotes. Quantitative comparisons demonstrate that SUMOylation predominantly enhances the stability of SUMO1 acceptors. Our study delivers a highly sensitive and efficient method for site-specific SUMOylome studies and provides a comprehensive catalogue of Arabidopsis SUMOylation, serving as a valuable resource with which to further explore how SUMOylation regulates protein function.

Genetic approach to discover a valuable gene for enhanced nutritional value in the edible filamentous fungus Fusarium venenatum

AbstractMycoprotein is critical in a dietary shift toward a more sustainable food system. However, the strain improvement for enhancing mycoprotein via genetic manipulation is lacking. Here, we investigated the functions of proteins related to ubiquitin and small ubiquitin‐like modifier (SUMO) modifications using a gene‐knockout strategy in Fusarium venenatum, a mycoprotein fungus closely related to the fungal genetics model species Fusarium graminearum. Among the candidate genes, we specifically focused on the putative SUMO‐associated gene UBQ14 based on phenotypic characteristics in F. graminearum. In the FvUBQ14 knockout mutant in F. venenatum, nutritional profiles showed prominent differences in amino acid and fatty acid composition compared to the wild‐type strain. Furthermore, through proteomic analysis, we confirmed that the loss of FvUBQ14 leads to metabolic changes, particular in amino acid biosynthesis and degradation, resulting in an increase in amino acid composition in F. venenatum. Our findings provide new insights into filamentous fungal food improvement through genetic engineering and contribute to advances in alternative protein industry.

SUMOylation and DeSUMOylation: Tug of War of Pain Signaling.

SUMOylation is a post-translational modification that attaches a small ubiquitin-like modifier (SUMO) group to a target protein via SUMO ligases, while deSUMOylation refers to the removal of this SUMO group by sentrin-specific proteases (SENPs). Although the functions of these processes have been well described in the nucleus, the role of SUMOylation and deSUMOylation in regulating ion channels is emerging as a novel area of study. Despite this, their contributions to pain signaling remain less clear. Therefore, this review consolidates the current evidence on the link(s) between SUMOylation, deSUMOylation, and pain, with a specific focus on ion channels expressed in the sensory system. Additionally, we explore the role of SUMOylation in the expression and function of kinases, vesicle proteins, and transcription factors, which result in the modulation of certain ion channels contributing to pain. Altogether, this review aims to highlight the relationship between SUMOylation and deSUMOylation in the modulation of ion channels, ultimately exploring the potential therapeutic role of these processes in chronic pain.

High-yield, plant-based production of an antimicrobial peptide with potent activity in a mouse model.

Plants offer a promising chassis for the large-scale, cost-effective production of diverse therapeutics, including antimicrobial peptides (AMPs). However, key advances will reduce production costs, including simplifying the downstream processing and purification steps. Here, using Nicotiana benthamiana plants, we present an improved modular design that enables AMPs to be secreted via the endomembrane system and sequestered in an extracellular compartment, the apoplast. Additionally, we translationally fused an AMP to a mutated small ubiquitin-like modifier sequence, thereby enhancing peptide yield and solubilizing the peptide with minimal aggregation and reduced occurrence of necrotic lesions in the plant. This strategy resulted in substantial peptide accumulation, reaching around 2.9 mg AMP per 20 g fresh weight of leaf tissue. Furthermore, the purified AMP demonstrated low collateral toxicity in primary human skin cells, killed pathogenic bacteria by permeabilizing the membrane and exhibited anti-infective efficacy in a preclinical mouse (Mus musculus) model system, reducing bacterial loads by up to three orders of magnitude. A base-case techno-economic analysis demonstrated the economic advantages and scalability of our plant-based platform. We envision that our work can establish plants as efficient bioreactors for producing preclinical-grade AMPs at a commercial scale, with the potential for clinical applications.

Novel approach to exploring protease activity and targets in HIV-associated obstructive lung disease using combined proteomic-peptidomic analysis

BackgroundObstructive lung disease (OLD) is increasingly prevalent among persons living with HIV (PLWH). However, the role of proteases in HIV-associated OLD remains unclear.MethodsWe combined proteomics and peptidomics to comprehensively characterize protease activities. We combined mass spectrometry (MS) analysis on bronchoalveolar lavage fluid (BALF) peptides and proteins from PLWH with OLD (n = 25) and without OLD (n = 26) with a targeted Somascan aptamer-based proteomic approach to quantify individual proteases and assess their correlation with lung function. Endogenous peptidomics mapped peptides to native proteins to identify substrates of protease activity. Using the MEROPS database, we identified candidate proteases linked to peptide generation based on binding site affinities which were assessed via z-scores. We used t-tests to compare average forced expiratory volume in 1 s per predicted value (FEV1pp) between samples with and without detection of each cleaved protein and adjusted for multiple comparisons by controlling the false discovery rate (FDR).FindingsWe identified 101 proteases, of which 95 had functional network associations and 22 correlated with FEV1pp. These included cathepsins, metalloproteinases (MMP), caspases and neutrophil elastase. We discovered 31 proteins subject to proteolytic cleavage that associate with FEV1pp, with the top pathways involved in small ubiquitin-like modifier mediated modification (SUMOylation). Proteases linked to protein cleavage included neutrophil elastase, granzyme, and cathepsin D.InterpretationsIn HIV-associated OLD, a significant number of proteases are up-regulated, many of which are involved in protein degradation. These proteases degrade proteins involved in cell cycle and protein stability, thereby disrupting critical biological functions.

Phosphorylation activates master growth regulator DELLA by promoting histone H2A binding at chromatin in Arabidopsis

DELLA proteins are conserved master growth regulators that play a central role in controlling plant development in response to internal and environmental cues. DELLAs function as transcription regulators, which are recruited to target promoters by binding to transcription factors (TFs) and histone H2A via their GRAS domain. Recent studies showed that DELLA stability is regulated post-translationally via two mechanisms, phytohormone gibberellin-induced polyubiquitination for its rapid degradation, and Small Ubiquitin-like Modifier (SUMO)-conjugation to increase its accumulation. Moreover, DELLA activity is dynamically modulated by two distinct glycosylations: DELLA-TF interactions are enhanced by O-fucosylation, but inhibited by O-linked N-acetylglucosamine (O-GlcNAc) modification. However, the role of DELLA phosphorylation remains unclear as previous studies showing conflicting results ranging from findings that suggest phosphorylation promotes or reduces DELLA degradation to others indicating it has no effect on its stability. Here, we identify phosphorylation sites in REPRESSOR OF ga1-3 (RGA, an AtDELLA) purified from Arabidopsis by mass spectrometry analysis, and show that phosphorylation of two RGA peptides in the PolyS and PolyS/T regions enhances RGA activity by promoting H2A binding and RGA association with target promoters. Notably, phosphorylation does not affect RGA-TF interactions or RGA stability. Our study has uncovered a molecular mechanism of phosphorylation-induced DELLA activity.

Protein SUMOylation and Its Functional Role in Nuclear Receptor Control

Post-translational protein modifications (PTMs) significantly enhance the functional diversity of proteins and are therefore important for the expansion and the dynamics of the cell’s proteome. In addition to structurally simpler PTMs, substrates also undergo modification through the reversible attachment of small proteins. The best understood PTM of this nature to date is the covalent conjugation of ubiquitin and ubiquitin-like proteins (UBLs) to their substrates. The protein family of small ubiquitin-like modifier (SUMO) is one of these UBLs that has received increasing scientific attention. The pathway of SUMOylation is highly conserved in all eukaryotic cells and is crucial for their survival. It plays an essential role in many biological processes, such as the maintenance of genomic integrity, transcriptional regulation, gene expression, and the regulation of intracellular signal transduction, and thereby influences DNA damage repair, immune responses, cell cycle progression, and apoptosis. Several studies have already shown that in this context protein SUMOylation is involved in the control mechanisms of various cellular receptors. This article unites data from different studies focusing on the investigation of the strictly conserved three-step enzyme cascade of protein SUMOylation and the functional analysis of the involved proteins E1, E2, and E3 and SUMOylation target proteins. Furthermore, this review highlights the role of nuclear receptor SUMOylation and its importance for the cellular functionality and disease development arising from defects in correct protein SUMOylation.

SUMO1 modification of 0N4R-tau is regulated by PIASx, SENP1, SENP2, and TRIM11

Tau is a microtubule-associated protein that contributes to cytoskeletal stabilization. Aggregation of tau proteins is associated with neurodegenerative disorders such as Alzheimer's disease. Several types of posttranslational modifications that alter the physical properties of tau proteins have been identified. SUMOylation is a reversible modification of lysine residues by a small ubiquitin-like modifier (SUMO). In this study, we examined the enzymes that regulate the SUMOylation and deSUMOylation of tau in an alternatively spliced form, 0N4R-tau. Among SUMO E3 ligases, we found protein inhibitor of activated STAT (PIAS)xα and PIASxβ increase the levels of SUMOylated tau. The deSUMOylation enzymes sentrin-specific protease (SENP)1 and SENP2 reduced the levels of SUMO-conjugated tau. SUMO1 modification increased the level of phosphorylated tau, which was suppressed in the presence of SENP1. Furthermore, we examined the effect of tripartite motif (TRIM)11, which was recently identified as an E3 ligase for SUMO2 modification of tau. We found that TRIM11 increased the modification of both 2N4R- and 0N4R-tau by SUMO1, which was attenuated by mutation of the target lysine residue to arginine. These findings suggest that the expression and activity of SUMOylation regulatory proteins modulate the physical properties of tau proteins and may contribute to the onset and/or progression of tau-associated neurodegenerative disorders.

Dual inhibition of SUMOylation and MEK conquers MYC-expressing KRAS-mutant cancers by accumulating DNA damage

BackgroundKRAS mutations frequently occur in cancers, particularly pancreatic ductal adenocarcinoma, colorectal cancer, and non-small cell lung cancer. Although KRASG12C inhibitors have recently been approved, effective precision therapies have not yet been established for all KRAS-mutant cancers. Many treatments for KRAS-mutant cancers, including epigenome-targeted drugs, are currently under investigation. Small ubiquitin-like modifier (SUMO) proteins are a family of small proteins covalently attached to and detached from other proteins in cells via the processes called SUMOylation and de-SUMOylation. We assessed whether SUMOylation inhibition was effective in KRAS-mutant cancer cells.MethodsThe efficacy of the first-in-class SUMO-activating enzyme E inhibitor TAK-981 (subasumstat) was assessed in multiple human and mouse KRAS-mutated cancer cell lines. A gene expression assay using a TaqMan array was used to identify biomarkers of TAK-981 efficacy. The biological roles of SUMOylation inhibition and subsequent regulatory mechanisms were investigated using immunoblot analysis, immunofluorescence assays, and mouse models.ResultsWe discovered that TAK-981 downregulated the expression of the currently undruggable MYC and effectively suppressed the growth of MYC-expressing KRAS-mutant cancers across different tissue types. Moreover, TAK-981-resistant cells were sensitized to SUMOylation inhibition via MYC-overexpression. TAK-981 induced proteasomal degradation of MYC by altering the balance between SUMOylation and ubiquitination and promoting the binding of MYC and Fbxw7, a key factor in the ubiquitin–proteasome system. The efficacy of TAK-981 monotherapy in immunocompetent and immunodeficient mouse models using a mouse-derived CMT167 cell line was significant but modest. Since MAPK inhibition of the KRAS downstream pathway is crucial in KRAS-mutant cancer, we expected that co-inhibition of SUMOylation and MEK might be a good option. Surprisingly, combination treatment with TAK-981 and trametinib dramatically induced apoptosis in multiple cell lines and gene-engineered mouse-derived organoids. Moreover, combination therapy resulted in long-term tumor regression in mouse models using cell lines of different tissue types. Finally, we revealed that combination therapy complementally inhibited Rad51 and BRCA1 and accumulated DNA damage.ConclusionsWe found that MYC downregulation occurred via SUMOylation inhibition in KRAS-mutant cancer cells. Our findings indicate that dual inhibition of SUMOylation and MEK may be a promising treatment for MYC-expressing KRAS-mutant cancers by enhancing DNA damage accumulation.

The polySUMOylation axis promotes nucleolar release of Tof2 for mitotic exit

In budding yeast, the nucleolus serves as the site to sequester Cdc14, a phosphatase essential for mitotic exit. Nucleolar proteins Tof2, Net1, and Fob1 are required for this sequestration. Although it is known that these nucleolar proteins are SUMOylated, how SUMOylation regulates their activity remains unknown. Here, we show that Tof2 exhibits cell-cycle-regulated nucleolar delocalization and turnover. Depletion of the nuclear small ubiquitin-like modifier (SUMO) protease Ulp2 not only causes Tof2 polySUMOylation, nucleolar delocalization, and degradation but also leads to Cdc14 nucleolar release and activation. This outcome depends on polySUMOylation and the activity of downstream enzymes, including SUMO-targeted ubiquitin ligase and Cdc48/p97 segregase. We further developed a system to tether SUMO machinery to Tof2 and generated a SUMO-deficient tof2 mutant, and the results indicate that Tof2 polySUMOylation is necessary and sufficient for its nucleolar delocalization and degradation. Together, our work reveals a polySUMO-dependent mechanism that delocalizes Tof2 from the nucleolus to facilitate mitotic exit.

Expression of SUMO and NF-κB genes in hepatitis B virus-associated hepatocellular carcinoma patients: An observational study.

Alterations in signaling pathways and modulation of cell metabolism are associated with the pathogenesis of cancers, including hepatocellular carcinoma (HCC). Small ubiquitin-like modifier (SUMO) proteins and NF-κB family play major roles in various cellular processes. The current study aims to determine the expression profile of SUMO and NF-κB genes in HCC tumors and investigate their association with the clinical outcome of HCC. The expression of 5 genes - SUMO1, SUMO2, SUMO3, NF-κB p65, and NF-κB p50 - was quantified in tumor and adjacent non-tumor tissues of 58 HBV-related HCC patients by real-time quantitative PCR and was analyzed for the possible association with clinical parameters of HCC. The expression of SUMO2 was significantly higher in HCC tumor tissues compared to the adjacent non-tumor tissues (P = .01), while no significant difference in SUMO1, SUMO3, NF-κB p65, and NF-κB p50 expression was observed between HCC tumor and non-tumor tissues (P > .05). In HCC tissues, a strong correlation was observed between the expression of SUMO2 and NF-κB p50, between SUMO3 and NF-κB p50, between SUMO3 and NF-κB p65 (Spearman rho = 0.83; 0.82; 0.772 respectively; P < .001). The expression of SUMO1, SUMO2, SUMO3, NF-κB p65, and NF-κB p50 was decreased in grade 3 compared to grades 1 and 2 in HCC tumors according to the World Health Organization grades system. Our results highlighted that the SUMO2 gene is upregulated in tumor tissues of patients with HCC, and is related to the development of HCC, thus it may be associated with the pathogenesis of HCC.

Targeting SUMOylation with an injectable nanocomposite hydrogel to optimize radiofrequency ablation therapy for hepatocellular carcinoma

BackgroundIncomplete radiofrequency ablation (iRFA) in hepatocellular carcinoma (HCC) often leads to local recurrence and distant metastasis of the residual tumor. This is closely linked to the development of a tumor immunosuppressive environment (TIME). In this study, underlying mechanisms and potential therapeutic targets involved in the formation of TIME in residual tumors following iRFA were explored. Then, TAK-981-loaded nanocomposite hydrogel was constructed, and its therapeutic effects on residual tumors were investigated.ResultsThis study reveals that the upregulation of small ubiquitin-like modifier 2 (Sumo2) and activated SUMOylation is intricately tied to immunosuppression in residual tumors post-iRFA. Both knockdown of Sumo2 and inhibiting SUMOylation with TAK-981 activate IFN-1 signaling in HCC cells, thereby promoting dendritic cell maturation. Herein, we propose an injectable PDLLA-PEG-PDLLA (PLEL) nanocomposite hydrogel which incorporates self-assembled TAK-981 and BSA nanoparticles for complementary localized treatment of residual tumor after iRFA. The sustained release of TAK-981 from this hydrogel curbs the expansion of residual tumors and notably stimulates the dendritic cell and cytotoxic lymphocyte-mediated antitumor immune response in residual tumors while maintaining biosafety. Furthermore, the treatment with TAK-981 nanocomposite hydrogel resulted in a widespread elevation in PD-L1 levels. Combining TAK-981 nanocomposite hydrogel with PD-L1 blockade therapy synergistically eradicates residual tumors and suppresses distant tumors.ConclusionsThese findings underscore the potential of the TAK-981-based strategy as an effective therapy to enhance RFA therapy for HCC.Graphic

Site-specific identification and quantitation of endogenous SUMOylation based on SUMO-specific protease and strong anion exchange chromatography

Small ubiquitin-like modifier (SUMO) modification regulates various eukaryotic cellular processes and plays a pivotal role in interferon (IFN)-mediated antiviral defense. While immunoprecipitation enrichment method is widely used for proteome-wide analysis of endogenous SUMOylation, the inability to target all SUMO forms and high cost of antibodies limited its further application. Herein, we proposed an antibody-free enrichment method based on SUMO-specific protease and strong anion exchange chromatography (SPAX) to globally profile the endogenous SUMOylation. The SUMO1/2/3-modified peptides could be simultaneously enriched by SAX chromatography by utilizing its electrostatic interaction with SUMO1/2/3 remnants, which contained multiple aspartic acids (D) and glutamic acids (E). To remove the co-enriched D/E-containing peptides which might interfere with the detection of low-abundance SUMOylated peptides, SUMO-specific protease was used to cleave the SUMO1/2/3 remnants from enriched SUMOylated peptides. As the deSUMOylated peptides lost SUMO remnants, their interaction with SAX materials became weaker, and the D/E-containing peptides could thus be depleted through the second SAX separation. The SPAX method identified over twice the SUMOylated sites than using SAX method only, greatly improving the identification coverage of endogenous SUMOylated sites. Our strategy was then applied to the site-specific identification and quantification of endogenous SUMOylation in A549 cells stimulated by IFN-γ for the first time. A total of 226 SUMOylated sites on 146 proteins were confidently identified, among which multiple up-regulated sites were involved in IFN-mediated antiviral defense, demonstrating the great promise of SPAX to globally profile and discover endogenous SUMOylation with significant biological functions.

Novel Approach to Exploring Protease Activity and Targets in HIV-associated Obstructive Lung Disease using Combined Proteomic-Peptidomic Analysis.

Obstructive lung disease (OLD) is increasingly prevalent among persons living with HIV (PLWH). However, the role of proteases in HIV-associated OLD remains unclear. We combined proteomics and peptidomics to comprehensively characterize protease activities. We combined mass spectrometry (MS) analysis on bronchoalveolar lavage fluid (BALF) peptides and proteins from PLWH with OLD (n=25) and without OLD (n=26) with a targeted Somascan aptamer-based proteomic approach to quantify individual proteases and assess their correlation with lung function. Endogenous peptidomics mapped peptides to native proteins to identify substrates of protease activity. Using the MEROPS database, we identified candidate proteases linked to peptide generation based on binding site affinities which were assessed via z-scores. We used t-tests to compare average forced expiratory volume in 1 second per predicted value (FEV1pp) between samples with and without detection of each cleaved protein and adjusted for multiple comparisons by controlling the false discovery rate (FDR). We identified 101 proteases, of which 95 had functional network associations and 22 correlated with FEV1pp. These included cathepsins, metalloproteinases (MMP), caspases and neutrophil elastase. We discovered 31 proteins subject to proteolytic cleavage that associate with FEV1pp, with the top pathways involved in small ubiquitin-like modifier mediated modification (SUMOylation). Proteases linked to protein cleavage included neutrophil elastase, granzyme, and cathepsin D. In HIV-associated OLD, a significant number of proteases are up-regulated, many of which are involved in protein degradation. These proteases degrade proteins involved in cell cycle and protein stability, thereby disrupting critical biological functions.

Yeast Small Ubiquitin-Like Modifier (SUMO) Protease Ulp2 is Involved in RNA Splicing.

In eukaryotes, RNA splicing, an essential biological process, is crucial for precise gene expression. Inaccurate RNA splicing can cause aberrant mRNA production, disrupting protein synthesis. To regulate splicing efficiency, some splicing factors are reported to undergo Ubiquitin-like Modifier (SUMO)ylation. Our data indicate that in Saccharomyces cerevisiae, the SUMO protease, Ulp2, is involved in splicing. In the ulp2Δ mutant, some ribosomal protein (RP) transcripts exhibited a significant increase in the levels of intron-containing pre-mRNA because of improper splicing. Moreover, we confirmed Ulp2 protein binding to the intronic regions of RP genes. These findings highlight a critical Ulp2 role in RP transcript splicing.

Enhancing glucaric acid production from myo-inositol in Escherichia coli by eliminating cell-to-cell variation.

Glucaric acid (GA) is a value-added chemical and can be used to manufacture food additives, anticancer drugs, and polymers. The non-genetic cell-to-cell variations in GA biosynthesis are naturally inherent, indicating the presence of both high- and low-performance cells in culture. Low-performance cells can lead to nutrient waste and inefficient production. Furthermore, myo-inositol oxygenase (MIOX) is a key rate-limiting enzyme with the problem of low stability and activity in GA production. Therefore, eliminating cell-to-cell variations and increasing MIOX stability can select high-performance cells and improve GA production. In this study, an in vivo GA bioselector was constructed based on GA biosensor and tetracycline efflux pump protein TetA to continuously select GA-efficient production strains. Additionally, the upper limit of the GA biosensor was improved to 40 g/L based on ribosome-binding site optimization, achieving efficient enrichment of GA high-performance cells. A small ubiquitin-like modifier (SUMO) enhanced MIOX stability and activity. Overall, we used the GA bioselector and SUMO-MIOX fusion in fed-batch GA production and achieved a 5.52-g/L titer in Escherichia coli, which was 17-fold higher than that of the original strain.IMPORTANCEGlucaric acid is a non-toxic valuable product that was mainly synthesized by chemical methods. Due to the problems of non-selectivity, inefficiency, and environmental pollution, GA biosynthesis has attracted significant attention. The non-genetic cell-to-cell variations and MIOX stability were both critical factors for GA production. In addition, the high detection limit of the GA biosensor was a key condition for performing high-throughput screening of GA-efficient production strains. To increase GA titer, this work eliminated the cell-to-cell variations by GA bioselector constructed based on GA biosensor and TetA, and improved the stability and activity of MIOX in the GA biosynthetic pathway through fusing the SUMO to MIOX. Finally, these approaches improved the GA production by 17-fold to 5.52 g/L at 65 h. This study represents a significant step toward the industrial application of GA biosynthetic pathways in E. coli.

Impact of RANGAP1 SUMOylation on Smad4 nuclear export by bioinformatic analysis and cell assays.

Small Ubiquitin-like Modifier (SUMOylation) regulates a variety of cellular activities, and its dysregulation has been associated with glioma etiology. The aim of this research was to clarify the function of SUMOylation-related genes in glioma and determine relevant prognostic markers. The Cancer Genome Atlas (TCGA) Glioma and GSE16011 datasets were analyzed through bioinformatics to identify Ran GTPase activating protein 1 (RANGAP1) as the hub gene for further study. Experimental validation consisted of quantitative real-time polymerase chain reaction (qRT-PCR), western blotting (WB), and immunoprecipitation (IP) to evaluate RANGAP1 expression, function, and interaction with SUMO1. To assess the role of RANGAP1 knockdown and SUMOylation in glioma cells, various assays were conducted, including cell proliferation, migration, invasion, and apoptosis. In addition, cell cycle analysis and immunofluorescence were performed. Through bioinformatics, RANGAP1 was identified as a crucial prognostic gene for glioma. Experimental studies confirmed the downregulation of RANGAP1 in glioma cells and verified that RANGAP1 repair impedes tumor growth. When it comes to RANGAP1 silencing, it enhanced cell proliferation, invasion and migration. Additionally, SUMO1 was identified as a specific SUMO molecule coupled to RANGAP1, affecting the location of Sma and Mad related protein 4 (Smad4) in the nucleocytoplasm and the transforming growth factor (TGF)-β/Smad signaling pathway. The functional impact of RANGAP1 SUMOylation on cell proliferation and migration was further confirmed through experiments using a SUMOylation-impairing mutation (K524R). Our findings suggest that RANGAP1 may be a potential prognostic marker in gliomas and could play a role in regulating cell proliferation, migration, and invasion. SUMOylation of RANGAP1 is responsible for regulating the TGF-β/Smad signaling pathway, which is crucial for the progression of tumors. Further investigations and experiments are necessary to confirm these results.

Juvenile dermatomyositis with Anti-SAE antibodies in a Moroccan child associated with pseudo-angioedema: a case report

BackgroundJuvenile Dermatomyositis (JDM) is the leading cause of non-infectious inflammatory myopathy in children. It is a heterogeneous group of autoimmune diseases characterized by a variable combination of muscular, dermatological, and visceral involvement. Myositis-specific autoantibodies help define homogeneous subgroups with common clinical characteristics and prognoses. Anti-SAE (small ubiquitin-like modifier 1 (SUMO-1) activating enzyme) antibodies are among the most recently discovered specific autoantibodies. The presence of these antibodies is very rare, making it challenging to define clinical features and prognosis in the juvenile form. We report the first case of an African patient with juvenile dermatomyositis and positive anti-SAE antibodies.Case ReportA 5-year-3-month-old Moroccan boy presented to the pediatric emergency department with dysphagia that had been evolving for two days, preceded two months earlier by facial erythema associated with fatigue, lower limb pain, difficulty walking, and progressive inflammatory polyarthralgia. On admission, the child had a heliotrope rash with predominant pseudo-angioedema on the lips, periungual telangiectasia, and Gottron’s papules over the bilateral interphalangeal and metatarsophalangeal joints. The patient had a more pronounced proximal muscle weakness in the lower limbs. He had no urticaria, fever, arthritis, calcinosis, cutaneous ulcers, or lipodystrophy. The Joint examination was normal, as was the pleuropulmonary examination. The electroneuromyography showed myogenic changes in all four limbs. Laboratory findings showed elevated levels of creatine phosphokinase and lactate dehydrogenase and a mild inflammatory syndrome. The electrocardiogram was normal. The anti-SAE antibodies were positive. The boy was diagnosed with juvenile dermatomyositis. He received methylprednisolone bolus therapy followed by oral prednisone. The latter was gradually tapered in combination with weekly intramuscular methotrexate. As a result, dysphagia disappeared within 48 h. After two weeks, there was an improvement in the muscular score and a significant regression of facial pseudo-angioedema.ConclusionWe report the first African patient with anti-SAE autoantibody-positive JDM. He had a typical dermatological manifestation of JDM associated with pseudo-angioedema predominant on the lips; a rarely reported sign in DM and JDM patients. The patient responded well to corticosteroid therapy and methotrexate.

The physical and evolutionary energy landscapes of devolved protein sequences corresponding to pseudogenes

Protein evolution is guided by structural, functional, and dynamical constraints ensuring organismal viability. Pseudogenes are genomic sequences identified in many eukaryotes that lack translational activity due to sequence degradation and thus over time have undergone "devolution." Previously pseudogenized genes sometimes regain their protein-coding function, suggesting they may still encode robust folding energy landscapes despite multiple mutations. We study both the physical folding landscapes of protein sequences corresponding to human pseudogenes using the Associative Memory, Water Mediated, Structure and Energy Model, and the evolutionary energy landscapes obtained using direct coupling analysis (DCA) on their parent protein families. We found that generally mutations that have occurred in pseudogene sequences have disrupted their native global network of stabilizing residue interactions, making it harder for them to fold if they were translated. In some cases, however, energetic frustration has apparently decreased when the functional constraints were removed. We analyzed this unexpected situation for Cyclophilin A, Profilin-1, and Small Ubiquitin-like Modifier 2 Protein. Our analysis reveals that when such mutations in the pseudogene ultimately stabilize folding, at the same time, they likely alter the pseudogenes' former biological activity, as estimated by DCA. We localize most of these stabilizing mutations generally to normally frustrated regions required for binding to other partners.

Knocking Down PIAS3 Reduces H2O2-induced Oxidative Stress Injury in HT22 Cells.

Oxidative stress is involved in the pathological processes of many neurodegenerative diseases. Protein modification by small ubiquitin-like modifiers (SUMOs) has been implicated in oxidative stress injury. By conjugating SUMOs to their selective protein substrates, SUMO ligases play critical roles in regulating functions of proteins involved in oxidative stress injury. In this study, we screened siRNAs to knockdown the SUMO ligase PIAS3 to assess its role in H2O2-induced injury in HT22 cells. H2O2 stimulation increased total protein SUMOylation, facilitated intracellular reactive oxygen species (ROS) release, increased cleaved caspase-3 levels, promoted p38 and JNK activation (phosphorylation), upregulated apoptosis, and decreased cell viability. The siRNA against PIAS3 329-347 (siPIAS3-329) markedly downregulated the protein expression of PIAS3 and reversed these effects, whereas siNC (negative control) had no effect. Our findings demonstrate that PIAS3-mediated SUMOylation facilitates oxidative stress injury and p38/JNK-mediated cell apoptosis and that PIAS3 is a potential target to protect against oxidative stress injury.