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Photocatalytic Golgi Proteomics Reveals Palmitoylation-Regulated Golgiphagy.

The Golgi apparatus (GA) orchestrates protein modification, trafficking, and secretion through highly dynamic remodeling, yet its proteomic complexity remains difficult to resolve in living systems. Here, we report CAT-Golgi, a genetically independent and light-controlled photocatalytic proximity labeling strategy for in situ spatiotemporal mapping of the Golgi-associated proteome. Combining a cysteine-conjugated eosin photocatalyst (GolgiCat) with an aniline probe, CAT-Golgi enables rapid and precise protein labeling within minutes under mild green light, requiring no genetic manipulation and operating efficiently in hard-to-transfect and primary cells. Leveraging our extensive efforts in organelle-targeted photocatalytic systems, we extended this chemistry to the highly dynamic and reversible Golgi apparatus. CAT-Golgi achieved quantitative and comparative proteomics in HeLa, K562, Jurkat and primary HEKa cells, revealing both conserved and cell-type-specific profiles. Under Brefeldin A-induced Golgiphagy, CAT-Golgi captured large-scale proteome remodeling and identified palmitoyl-protein thioesterase 1 (PPT1) as a potential regulatory component. PPT1 downregulation enhanced ULK1 and TRPML1 palmitoylation, disrupted redox balance, and activated Golgiphagy. CAT-Golgi provides a broadly applicable chemical platform for decoding organelle dynamics, offering both conceptual and technical foundations for extending photocatalytic proteomics to other transient organelles and illuminating molecular mechanisms of organelle plasticity and disease progression.

Golgi Apparatus

SARS-CoV-2 remodels the Golgi apparatus to facilitate viral assembly and secretion.

The COVID-19 pandemic is caused by the enveloped virus SARS-CoV-2. Despite extensive investigation, the molecular mechanisms for its assembly and secretion remain largely elusive. Here, we show that SARS-CoV-2 infection induces global alterations of the host endomembrane system, including dramatic Golgi fragmentation. SARS-CoV-2 virions are enriched in the fragmented Golgi. Blocking endoplasmic reticulum (ER) to Golgi trafficking dramatically inhibits SARS-CoV-2 assembly and secretion without reducing viral genome replication. Significantly, SARS-CoV-2 infection down-regulates GRASP55 but up-regulates TGN46 protein levels. Surprisingly, GRASP55 expression reduces both viral secretion and spike number on each virion without affecting viral entry, while GRASP55 depletion displays opposite effects. In contrast, TGN46 depletion only inhibits viral secretion without affecting spike incorporation into virions. Taken together, we show that SARS-CoV-2 alters Golgi structure and function to modulate viral assembly and secretion, highlighting the Golgi as a potential therapeutic target for blocking SARS-CoV-2 infection.

Golgi Apparatus

Golgi_traff phylogeny reveals ancient eukaryotic genes with recent surprises: replication and diversification of HID1 domain-containing protein unique to Schizosaccharomyces.

Golgi_traff is a Pfam clan containing two members, Dymeclin (DYM) and HID1 domain-containing protein (HID). Interrogation of over 900 eukaryotic genomes with sequence models showed that both are ancient eukaryotic genes, which have exhibited different paths of gene loss, including from major taxonomic groups. For example, the Metazoa have both genes, whereas the Viridiplantae and Dikarya have lost HID and DYM, respectively. A unique replication event occurred within the genus Schizosaccharomyces in that all sequenced species possess three HID-encoding paralogs, whereas its nearest fungal relatives and other eukaryotes are almost exclusively monogenic. A phylogenetic analysis of yeasts revealed that the Golgi-resident paralog Human ortholog 3 (SPAC17A5.16) is more similar to the HID of other yeasts than to its paralogs. Transmission electron microscopy revealed that the SPAC17A5.16 mutant lacks a stacked Golgi apparatus (GA) form, suggesting a role in maintaining GA structure. Altered proliferation of the SPAC17A5.16 mutant in response to GA disrupting chemical agents indicated a perturbation of GA-related functions. Structural models suggest SPAC17A5.16 has a long, disordered N-terminal region that may facilitate anchoring to GA membranes. A modification to Schizosaccharomyces HID nomenclature is proposed to reflect their evolutionary and functional characteristics. The potential of the Golgi_traff clan to serve as a model for the diversification of protein function according to the concepts of sub/neofunctionalization is discussed.

Schizosaccharomyces

Loss of function of FAM177A1, a Golgi complex localized protein, causes a novel neurodevelopmental disorder.

PURPOSE: The function of FAM177A1 and its relationship to human disease is largely unknown. Recent studies have demonstrated FAM177A1 to be a critical immune-associated gene. One previous case study has linked FAM177A1 to a neurodevelopmental disorder in 4 siblings. METHODS: We identified 5 individuals from 3 unrelated families with biallelic variants in FAM177A1. The physiological function of FAM177A1 was studied in a zebrafish model organism and human cell lines with loss-of-function variants similar to the affected cohort. RESULTS: These individuals share a characteristic phenotype defined by macrocephaly, global developmental delay, intellectual disability, seizures, behavioral abnormalities, hypotonia, and gait disturbance. We show that FAM177A1 localizes to the Golgi complex in mammalian and zebrafish cells. Intersection of the RNA sequencing and metabolomic data sets from FAM177A1-deficient human fibroblasts and whole zebrafish larvae demonstrated dysregulation of pathways associated with apoptosis, inflammation, and negative regulation of cell proliferation. CONCLUSION: Our data shed light on the emerging function of FAM177A1 and defines FAM177A1-related neurodevelopmental disorder as a new clinical entity.

Humans

Proinsulin regulators identified with CRISPR screen and in vivo mouse QTL mapping.

Altered proinsulin levels in β-cells and bloodstream are hallmarks of diabetes and other diseases, but our knowledge about the proinsulin regulators remains limited. Here we perform a genome-wide CRISPR screen to identify 84 proinsulin regulators that alter intracellular proinsulin/insulin ratio in a mouse β-cell line. The proinsulin regulators are distinct from the insulin regulators from a previous orthogonal CRISPR screen. Functional annotation of the proinsulin regulators highlights Golgi as the primary organelle for proinsulin storage and regulation. Trafficking towards the Golgi increases the intra-cellular proinsulin/insulin ratio, while trafficking away from the Golgi, including exocytosis and Golgi-to-ER retrograde transport, decreases the intracellular proinsulin levels. We also map mouse quantitative trait loci (QTLs) associated with plasma proinsulin levels and use the CRISPR screen results to pinpoint the causal genes within the QTL loci. Interestingly, protein disulfide isomerase Pdia6 is the strongest hit from both CRISPR screen and the in vivo QTL mapping. Knocking down Pdia6 significantly reduce proinsulin accumulation in Golgi and secretory granules. Intriguingly, Pdia6-depletion in both human and mouse β-cells does not affect the folding status of proinsulin but causes significantly impaired proinsulin production through a UPR-independent mechanism. Taken together, our genetic profiles provide mechanistic insights into the regulation of proinsulin/insulin homeostasis.

Animals

COG6 is an essential host factor for influenza A virus infection.

Influenza A virus (IAV) relies on the host cellular machinery to support its replication. Understanding these host dependencies can inform the development of novel antiviral strategies. In this study, we identified conserved oligomeric Golgi complex subunit 6 (COG6) as a novel host factor critical for IAV replication through a genome-wide clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) knockout screen. Disruption of COG6 significantly impaired viral replication. Mechanistically, COG6 supports IAV replication via two distinct means. First, consistent with the role of the COG complex in Golgi homeostasis, COG6 is required for the proper presentation of surface sialic acids, the primary receptor for IAV entry. Second, COG6 deficiency unexpectedly led to lysosome-dependent degradation of viral proteins. Notably, lysosomal activity was also upregulated in IAV-infected wild-type cells, albeit to a lesser extent than in COG6-deficient cells. Treatment with lysosomal inhibitors rescued viral protein stability in COG6 knockout cells. Protein interaction analysis further demonstrated that COG6-mediated stabilization of viral proteins did not rely on viral protein-COG6 interaction, refuting the hypothesis that COG6 acts as a shield factor to protect viral protein from lysosomal degradation. Moreover, knockout of other COG subunits produced similar antiviral effects, suggesting that an intact COG complex is required for IAV replication. Together, these findings uncover a critical role of the COG complex in regulating IAV replication and highlight a previously unappreciated functional link between the Golgi and lysosomes that could be exploited for treating IAV infections.IMPORTANCEDespite advances in virology, numerous host determinants facilitating influenza A virus (IAV) pathogenesis remain uncharacterized. Our study establishes conserved oligomeric Golgi complex subunit 6 (COG6) as a critical host factor promoting IAV infection through complementary mechanisms: receptor modulation and viral protein stabilization. This represents the first demonstration that the COG complex regulates viral pathogenesis through proteostasis mechanisms, fundamentally expanding our understanding of host-virus interactions at the organelle interface. These findings not only provide new perspectives on viral exploitation of Golgi trafficking networks but also identify potential therapeutic targets against evolving influenza strains.

Influenza A virus

STING inhibits LINE-1 retrotransposition through sorting ORF1p to lysosomes for degradation.

The cyclic dinucleotide sensor stimulator of interferon (IFN) genes (STING) is known for its critical role in interferon and inflammatory responses. In addition, STING also has functions independent of interferon induction. In this study, we report that STING restricts the mobilization of the cellular retrotransposon long interspersed nuclear element 1 (LINE-1) independent of cGAS and interferon induction. LINE-1 is the only active autonomous retrotransposable element in the human genome and its transposition can cause genetic and autoimmune diseases. STING inhibition of LINE-1 requires its dimerization. Mechanistically, STING interacts with LINE-1 ORF1p, then the complex translocates to the ER-Golgi intermediate compartment (ERGIC) and the Golgi followed by sorting to Rab7-positive lysosomes for degradation. Our data unveil a function of STING in maintaining host genome integrity by restricting LINE-1 retrotransposition via an IFN-independent mechanism.

Humans

CRISPR/Cas9 loss-of-function screen in a neuronal model of AP-4 deficiency identifies ATG9A trafficking modulators.

Biallelic loss-of-function variants in adaptor protein complex 4 (AP-4) disrupt trafficking of transmembrane proteins at the trans-Golgi network, including autophagy-related protein 9A (ATG9A), leading to childhood-onset hereditary spastic paraplegia (AP-4-HSP). AP-4-HSP is characterized by features of both a neurodevelopmental and a degenerative neurological disease. To investigate the molecular mechanisms underlying AP-4-HSP and identify potential therapeutic targets, we conducted an arrayed CRISPR/Cas9 loss-of-function screen of 8,478 genes, targeting the "druggable genome," in a human neuronal model of AP-4 deficiency. Through this phenotypic screen and subsequent experiments, key modulators of ATG9A trafficking were identified, and complementary pathway analyses provided insights into the regulatory landscape of ATG9A transport. Knockdown of ANPEP and NPM1 enhanced ATG9A availability outside the trans-Golgi network, suggesting that they regulate ATG9A localization. These findings deepen our understanding of ATG9A trafficking in the context of AP-4 deficiency and offer a framework for the development of targeted interventions for AP-4-HSP.

Humans

A subcomplex comprising TRAPPC11, TRAPPC12, TRAPPC13 and the fungal TRAPPC2L homolog, Tca17, directs TRAPPIII to autophagy.

Transport protein particle complexes (TRAPPs) are master regulators of membrane trafficking. TRAPPs are targeted to different locales by pathway-specific subunits decorating a core hetero-heptamer to build TRAPPII (Golgi exit) and TRAPPIII (autophagosomes and ER-Golgi trafficking). Metazoan and Arabidopsis TRAPPIII have three components, TRAPPC11, TRAPPC12 and TRAPPC13 (hereafter denoted TRAPPC11/12/13), that are absent from budding yeast. We studied TRAPPC11/12/13 in the related ascomycete Aspergillus nidulans, where TRAPPC11 and TRAPPC12 localize to pre-autophagosomes and their ablation impairs autophagy. We found that two stable subcomplexes containing Tca17, the homolog of metazoan TRAPPC2L, coexist - one includes the TRAPPII-specific subunits Trs120, Trs130 and Trs65 whereas the other contains the TRAPPIII-specific subunits TRAPPC11/12/13. Both are recruited to core TRAPP by Tca17, which therefore plays a crucial role by determining the physiological role of TRAPP. TRAPPIII also exists in two versions, TRAPPIIIa and TRAPPIIIb, both of which contain Trs85, the homolog of metazoan TRAPPC8, but with only TRAPPIIIb containing TRAPPC11/12/13, which target TRAPPIII to autophagy. This study might help characterize potentially pathogenic mutations affecting human TRAPPC11/12/13, facilitating assessment of their functional consequences in a genetically amenable ascomycete.

Autophagy

Identification of a novel signature for prognostic stratification and integrative analyses in lung adenocarcinoma.

BACKGROUND: Recently, research has revealed that the Golgi apparatus is involved in the development process of cancer; however, the specific effect of Golgi apparatus-related genes (GAGs) in lung adenocarcinoma (LUAD) remains unclear. This study aims to construct a more concise and practical risk model in LUAD using GAG. METHODS: The gene expression profiles of patients with LUAD were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, and GAGs were downloaded from the Gene Set Enrichment Analysis (GSEA) database. Univariate Cox and least absolute shrinkage and selection operator (LASSO) analyses were performed to identify the prognostic GAG signature. Kaplan-Meier and receiver operating characteristic (ROC) curves were plotted to validate the predictive effect of the prognostic signatures. The correlation between the risk model and the immune landscape was examined using CIBERSORT and TIDE analyses. Also, the genes in the signature were assessed by single-cell RNA sequencing (scRNA-seq). RESULTS: A prognostic signature comprising 5 GAG genes (GNPNAT1, RGS20, CAV3, NTSR1, and FURIN) was established after LASSO and multi-Cox analyses. Both the Kaplan-Meier analysis and the ROC curves supported the strong predictive utility of the risk model. Specifically, the former yielded significant stratification in all three validation datasets (P=1.2001e-05, P=0.006, and P=0.04), while the latter provided further evidence of its predictive precision through the area under the curve. In addition, we found that the low-risk group responded better to immunotherapy than the high-risk group (P<0.0001). scRNA-seq analysis revealed the distribution patterns of the 5 GAG genes in cells. Finally, we assessed the situation of tumor mutation burden (TMB) and performed functional analysis based on the risk model of GAGs. CONCLUSIONS: The risk model based on GAGs can effectively stratify the prognosis of patients and predict immunotherapy responses in LUAD.

Golgi apparatus

Elucidating the In&#xa0;Vitro Adverse Effect of Functionalized Single-Walled Carbon Nanotubes Against Breast Cancer Cells at the Proteomics Level.

The tremendous therapeutic potential of carbon-based nanomaterials (CNMs) has been limited by inconsistent data regarding the nanotoxicity assessment. Although a bulk of studies have been performed to assess the in&#xa0;vitro cytotoxicity mechanism of CNMs, the exact factors responsible for the cytotoxicity of CNMs have not been fully understood. With the rapid advancement of mass spectrometry technologies, proteomics has emerged as a powerful strategy for systematically investigating the molecular and cellular mechanisms underlying toxicity induced by nanomaterials. This study examined the in&#xa0;vitro cytotoxicity of single-walled carbon nanotubes (SWCNTs) in human MCF-7 breast cancer cells by conducting a comparative proteome-level analysis using mass spectrometry. Initially, the characterized SWCNTs were incubated with MCF-7 cells for 3, 6, and 24&#x2009;h. Proteins were subsequently extracted from each treatment group and subjected to nano-liquid chromatography-tandem mass spectrometry (nLC-MS/MS) analysis. The relative abundance of the identified proteins was determined by comparison with the control group, and differential expression patterns, including upregulated and downregulated proteins, were assessed. A total of 3482 unique protein groups were identified across all exposure periods. Among these, 3466 protein groups were detected following 3&#x2009;h of exposure, 3469 following 6&#x2009;h of exposure, and 3480 following 24&#x2009;h of exposure. Compared with the control group, the identified differentially expressed proteins exhibited fold changes ranging from 2-fold to 20-fold across the incubation periods. In total, 70 proteins were found to be significantly regulated following SWCNT exposure. Of the differentially expressed proteins, 45 were significantly upregulated, whereas 25 were significantly downregulated. Visualization of these regulations over time was shown in a heatmap of log2-transformed fold-change values to explore time-specific proteomic alterations. Functional enrichment analysis of these proteins also showed that the regulated proteins were significantly associated with Reactome pathways, including ER-to-Golgi anterograde transport, Golgi-to-ER retrograde transport, COPI-mediated vesicle trafficking, regulation of insulin-like growth factor transport and uptake by insulin-like growth factor-binding proteins, protein metabolism, and posttranslational protein modification. Furthermore, a systematic comparison of previous studies within the present findings was provided to situate our study within the broader context of understanding CNT-induced cellular toxicity. Collectively, these findings provided an important proteomic evidence of the adverse effects of SWCNTs on MCF-7 cells. Furthermore, this study showed a comprehensive proteomic landscape of cellular responses to SWCNT exposure, contributing to a better understanding of the molecular mechanisms underlying SWCNT-induced cytotoxicity and bridging the gap between protein regulation and the resulting cellular responses. In this study, we characterized the proteomic landscape of MCF-7 cells following SWCNT exposure, revealing molecular mechanisms associated with cellular responses and cytotoxicity. The identified differentially expressed proteins established a link between altered protein regulation and SWCNT-induced cellular effects. Moreover, these proteins need to be further validated in different cell models and would potentially represent promising candidates for the identification of novel molecular targets involved in SWCNT-induced cytotoxicity.

MCF&#x2010;7 cells

YIPF&#x3b1;1A expression is regulated by multilayered molecular mechanisms.

Yip domain family (YIPF) proteins are five-pass transmembrane proteins that localize primarily to the Golgi apparatus. These proteins assemble into higher-order complexes with each &#x3b1;-subunit pairing specifically with a &#x3b2;-subunit to form a dimer which then assemble into complexes with two to four dimers. Notably, &#x3b2;-subunit expression depends on the corresponding &#x3b1;-subunit partner, and conventional transient overexpression of &#x3b1;-subunits has been extremely inefficient, hindering deeper analysis of YIPF complexes. To identify the cause of poor exogenous expression, we examined YIPF gene features and found two properties correlated with low expression: (i) rare-codon enrichment in the CDS and (ii) extended 3' UTRs. Experimental analyses focusing on YIPF&#x3b1;1A revealed that rare-codon enrichment suppresses expression mainly at the mRNA level, consistent with translation-coupled mRNA decay, whereas inclusion of the native 3'&#xa0;UTR enhances expression by increasing mRNA abundance. Deletion mapping further showed that a proximal 3' UTR segment (51-150) is necessary and sufficient for mRNA stabilization, thereby elevating both mRNA and protein levels. Conversely, a distal 3' UTR fragment (1116-2230) increased mRNA but not protein levels, suggesting translational repression resulting in a reduced protein-to-mRNA ratio. Together, these findings explain the discrepancy between endogenous and exogenous YIPF&#x3b1;1A expression and propose a multilayered regulatory model in which rare codons decrease mRNA, the proximal 3' UTR stabilizes mRNA, and the distal 3' UTR reduces translation. Impact statement Our work advances YIPF biology and identifies post&#x2011;transcriptional mechanisms governing multi&#x2011;pass membrane proteins. We show rare&#x2011;codon and 3' UTR&#x2011;based control of trafficking proteins-an area largely unexplored-and introduce a new paradigm for membrane&#x2011;traffic regulation that will guide future studies of complex assembly, localization, and homeostasis.

3' Untranslated Regions

Host ESCRT machinery orchestrates the assembly of tomato spotted wilt virus ribonucleoproteins.

The genomic RNA of negative-strand RNA viruses is encapsidated by nucleocapsid proteins and associates with RNA polymerase to form a ribonucleoprotein (RNP) complex. Lacking both a 5' cap and a 3' poly (A) tail, viral RNAs are highly unstable and prone to degradation by cellular nucleases. Therefore, newly synthesized genomic and complementary-strand RNAs must be rapidly protected through RNP formation. However, the molecular mechanisms governing RNP assembly in cytoplasm-replicating negative-strand RNA viruses remain largely unknown. Here, we screened a yeast knockout library and isolated mutants in several components of the endosomal sorting complexes required for transport (ESCRT) genes that affected RNA replication of tomato spotted wilt virus (TSWV). In wild-type (WT) yeast cells, TSWV nucleocapsid (N) and RNA polymerase (L) proteins colocalize at the trans-Golgi network (TGN) in a replicon-RNA-dependent manner, suggesting that TSWV RNPs accumulate at the TGN. However, in the snf7&#x394;, bro1&#x394;, and doa4&#x394; mutant cells, N localization to TGN and RNP formation were impaired. Another RNA replication-defective mutant, vps36&#x394;, showed normal N localization, and SNF7, BRO1, and DOA4 were recruited to the TGN by TSWV N or L proteins, implying that the ESCRT components have additional roles in TSWV RNA replication beyond facilitating N transport. These findings suggest that ESCRT components play multifaceted roles in TSWV RNA replication, including the intracellular transport of N to the TGN-where RNA replication takes place-thereby ensuring accurate and efficient RNP assembly.

Tospovirus

Diversity of microtubule arrays in animal cells at a glance.

Microtubules are cytoskeletal filaments important for various cellular processes such as intracellular transport, cell division, polarization and migration. Microtubule organization goes hand in hand with cellular function. Motile cells, such as immune cells or fibroblasts, contain microtubule asters attached to the centrosome and the Golgi complex, whereas in many other differentiated cells, microtubules form linear arrays or meshworks anchored at membrane-bound organelles or the cell cortex. Over the past decade, new developments in cell culture, genome editing and microscopy have greatly advanced our understanding of complex microtubule arrays. In this Cell Science at a Glance article and the accompanying poster, we review the diversity of microtubule arrays in interphase animal cells. We describe microtubule network geometries present in various differentiated cells, explore the variety in microtubule-organizing centers responsible for these geometries, and discuss examples of microtubule reorganization in response to functional changes and their interplay with cell motility and tissue development.

Microtubules

Genetic Conservation and Diversity of SARS-CoV-2 Envelope Gene Across Variants of Concern.

SARS-CoV-2 Envelope (E) protein is critical in viral assembly, release, and virulence. E gene was considered highly conserved and evolving slowly. Pan-sarbecoviruses-conserved regions in the E gene have been used as targets for various RT-PCR assays to detect SARS-CoV-2. It remains elusive whether SARS-CoV-2 variants of concern (VOCs) have accumulated significant E mutations that may affect protein stability and diagnostic RT-PCR assays. Herein we aimed to perform a comprehensive genetic analysis on the conservation and diversity of the E gene of SARS-CoV-2 and its VOCs in comparison with other human coronaviruses (HCoVs). In silico analysis of 20&#x2009;326 HCoV E gene sequences retrieved from GenBank and GISAID suggests that SARS-CoV-2 E gene has multiple pan-HCoVs- and pan-SARS-CoV-2-conserved positions but accumulates significant mutations in VOC B.1.351 and Omicron strains. Mutations were often found in the 5' and 3' variable regions, whereas the central region is conserved. Nucleotide changes C109U and A114G may lead to potential failure of first-line SARS-CoV-2 diagnostic/screening assays. Nucleotide change C212U and its concomitant amino acid substitution Pro71Leu (i.e., C212U/Pro71Leu) is a hallmark mutation of B.1.351 variants, while C26U/Thr9Ile is characteristic of all Omicron variants. Later Omicron subvariants, such as XBB.1.5 and EG.5, additionally acquired the A31G/Thr11Ala mutation, as was confirmed by whole genome sequencing of SARS-CoV-2 in 118 pediatric cases. Wild-type E protein exhibits cytotoxicity to cells, but the mutations Thr9Ile, Thr11Ala, Thr9Ile&#xa0;+&#xa0;Thr11Ala, or Pro71Leu reduces its cytotoxicity. The Thr9Ile&#xa0;+&#xa0;Thr11Ala mutation stabilizes the E proteins of Omicron variants, while Pro71Leu alters the cellular distribution of the E protein, reducing its colocalization with the Golgi body. Altogether, this study not only sheds light on the conservation and diversity of the E gene in SARS-CoV-2 and its VOCs but also informs the improvement and development of SARS-CoV-2 or pan-HCoVs screening and diagnostic assays.

SARS-CoV-2

N-Glycosylation Deficiency in Transgene &#x3b1;7 nAChR and RIC3 Expressing CHO Cells Without NACHO.

The human neuronal nicotinic acetylcholine receptor &#x3b1;7 (nAChR) is an important target implicated in diseases like Alzheimer's or Parkinson's, as well as a validated target for drug discovery. For &#x3b1;7 nAChR model systems, correct folding and ion influx functions are essential. Two chaperones, resistance to inhibitors of cholinesterase 3 (RIC3) and novel nAChR regulator (NACHO), enhance the assembly and function of &#x3b1;7 nAChR. This study investigates the consequence of NACHO absence on &#x3b1;7 nAChR expression and function. Therefore, the sequences of human &#x3b1;7 nAChR and human RIC3 were transduced in Chinese hamster ovary (CHO) cells. Protein expression and function of &#x3b1;7 nAChR were confirmed by Western blot and voltage clamp, respectively. Cellular viability was assessed by cell proliferation and lactate dehydrogenase assays. Intracellular and extracellular expression were determined by in/on-cell Western, compared with another nAChR subtype by novel cluster fluorescence-linked immunosorbent assay, and N-glycosylation efficiency was assessed by glycosylation digest. The transgene CHO cell line showed expected protein expression and function for &#x3b1;7 nAChR and cell viability was barely influenced by overexpression. While intracellular levels of &#x3b1;7 nAChR were as anticipated, plasma membrane insertion was low. The glycosylation digest revealed no appreciable N-glycosylation product. This study demonstrates a stable and functional cell line expressing &#x3b1;7 nAChR, whose protein expression, function, and viability are not affected by the absence of NACHO. The reduced plasma membrane insertion of &#x3b1;7 nAChR, combined with incorrect matured N-glycosylation at the Golgi apparatus, suggests a loss of recognition signal for lectin sorting.

Animals

Restraint of inflammasome-driven cytokine responses through the mRNA stability protein TTP.

Activation of the NLRP3 inflammasome causes extensive disturbance of cellular homeostasis, with Golgi disruption, mitochondrial dysfunction, and changes in intracellular ion concentration occurring rapidly upon stimulation. Given this, it would seem near certain that these changes might also globally affect cellular signaling pathways, yet few, if any, studies have explored this possibility. Here, we combine genomics and phosphoproteomics to identify inhibition of the ERK1/2 MAP kinase signaling cascade upon inflammasome stimulation. This loss of ERK1/2 activity results in rapid inactivation of the mRNA decay-promoting protein tristetraprolin (TTP), with loss of TTP promoting subsequent increased release of cytokines upon pyroptosis. Further, we observe significantly increased levels of TTP expression in patients with inflammatory bowel disease, a disease for which altered cytokine expression is a key driver of pathogenesis. Inflammasome activation thus rapidly inactivates a pathway designed to suppress cytokine release, potentially exacerbating hyperinflammatory states, including those involved in autoinflammatory disease.

Inflammasomes

Comprehensive bioinformatics analysis identifies candidate ciliogenesis-related genes preferentially associated with N0-stage lung squamous cell carcinoma.

PURPOSE: There is few research on which genes play an important role in tumors without lymph metastasis. This study aimed to identify candidate molecular alterations preferentially associated with N0-stage LUSC. METHODS: we conducted a comprehensive bioinformatics analysis using publicly available The Cancer Genome Atlas (TCGA) data. Differentially expressed genes (DEGs) were identified separately by comparing N0 tumors and N+ tumors with normal lung tissues. Genes dysregulated in both N0 and N+ tumors were excluded to identify candidate N0-associated genes PPI networks were constructed using STRING and Cytoscape, with module analysis performed via MCODE. Hub genes were identified using multiple Cytohubba algorithms. Functional enrichment analyses were conducted using GO, and KEGG pathways using DAVID. Gene interaction networks were further explored using GeneMANIA. Immune cell infiltration was evaluated with TIMER. Associations with pathological stage and patient survival were assessed using GEPIA and other relevant tools. RESULTS: A total of 1103 candidate N0-associated DEGs were identified, including 748 upregulated and 355 downregulated genes. The PPI network contained five major MCODE clusters. One cluster (MCODE 4) included TTC30A, TTC30B, BBS7, and KIF3B genes implicated in ciliogenesis. TTC30B showed significant differential expression across pathological stages in the overall LUSC cohort. Seven consensus hub genes (ERBB2, CHUK, CASP8, NOTCH1, HNF4A, CREBBP, and IRS1) were identified based on their consistent ranking across multiple CytoHubba algorithms. Upregulated candidate N0-associated genes were primarily enriched in immune-related processes, including B-cell-mediated immunity and humoral responses, whereas downregulated genes were enriched in lysosomal and trans-Golgi network-related pathways. Exploratory immune infiltration analyses identified associations between the four ciliogenesis-related genes and several immune cell populations. CONCLUSIONS: This study identified candidate molecular signatures preferentially associated with N0-stage LUSC, including ciliogenesis-related genes and consensus hub genes. These findings provide hypotheses regarding molecular features of N0-stage LUSC and warrant further validation in independent cohorts and experimental studies.

Humans