MALT1 has been implicated as an upstream regulator of NF-κB signaling in immune cells and tumors. This study determined the regulatory mechanisms and biological functions of MALT1 in non-small cell lung cancer (NSCLC). In cell culture and orthotopic xenograft models, MALT1 suppression via gene expression interference or protein activity inhibition significantly impaired malignant phenotypes and enhanced radiation sensitivity of NSCLC cells. CSN5, the core subunit of COP9 signalosome, was firstly verified to stabilize MALT1 via disturbing the interaction with E3 ligase FBXO3. Loss of FBXO3 in NSCLC cells reduced MALT1 ubiquitination and promoted its accumulation, which was reversed by CSN5 interference. An association between CSN5/FBXO3/MALT1 regulatory axis and poor prognosis in NSCLC patients was identified. Our findings revealed the detail mechanism of continuous MALT1 activation in NF-κB signaling, highlighting its significance as predictor and potential therapeutic target in NSCLC.

The constitutive photomorphogenesis 9 (COP9) signalosome (CSN) typically composing of eight subunits (CSN1-8) mediates the process of deneddylation and deubiquitination. The fifth subunit of COP9 signalosome, CSN5, has special characteristics compared with the other seven subunits, and plays vital roles in the deneddylation activity and diverse cellular processes. However, the role of CSN5 in antiviral immunity is not clear. In this study, we identified 8 subunits (CSN1-8) of COP9 signalosome in shrimp Marsupenaeus japonicus. CSN1-6 were existed in all tested tissues, but CSN7-CSN8 were not detected in hepatopancreas. After WSSV challenged, the expression level of Csn1 to Csn4, and Csn6 to Csn8 were highly decreased, but the expression level of Csn5 was conspicuously increased in shrimp challenged by white spot syndrome virus (WSSV). The CSN5 was recombinantly expressed in Escherichia coli and its polyclonal antibody was prepared. The expression level of CSN5 was conspicuously increased at RNA and protein levels in the shrimp challenged by WSSV. After knockdown of Csn5 by RNA interference, the WSSV replication was obviously increased in shrimp. When injected the recombinant protein of CSN5 with the membrane penetrating peptide into shrimp, WSSV replication was inhibited and the survival rate of shrimp was significantly improved compared with control. We further analyzed the expression of antimicrobial peptides (AMPs) in Csn5-RNAi shrimp, and the results showed that the expression of several AMPs was declined significantly. These results indicate that CSN5 inhibits replication of WSSV via regulating expression of AMPs in shrimp, and the recombinant CSN5 might be used in shrimp aquaculture for the white spot syndrome disease control.

Multiple Endocrine Neoplasia 1 gene (MEN1), which is known to be a tumor suppressor gene in lung tissues, encodes a 610 amino acid protein menin. Previous research has proven that MEN1 deficiency promotes the malignant progression of lung cancer. However, the biological role of this gene in the immune microenvironment of lung cancer remains unclear. In this study, we found that programmed cell death-ligand 1 (PD-L1) is upregulated in lung-specific KrasG12D mutation-induced lung adenocarcinoma in mice, after Men1 deficiency. Simultaneously, CD8+ and CD3+ T cells are depleted, and their cytotoxic effects are suppressed. In vitro, PD-L1 is inhibited by the overexpression of menin. Mechanistically, we found that MEN1 inactivation promotes the deubiquitinating activity of COP9 signalosome subunit 5 (CSN5) and subsequently increases the level of PD-L1.

Hepatocellular carcinoma (HCC) is among the most common deadly tumors but still lacks specific biomarkers for diagnosis, prognosis, and treatment guidance. The COP9 signalosome (COPS) is an essential regulator of the ubiquitin conjugation pathway upregulated in various cancers. We evaluated the contributions of COPS subunits to HCC tumorigenesis and their utility for prognosis. We comprehensively evaluated the tumor expression pattern and tumorigenic functions of COPS subunits using The Cancer Genome Atlas (TCGA), The Human Protein Atlas and immunohistochemistry. Kaplan-Meier, Cox regression, ROC curve, and nomogram analyses were used to assess the predictive values of COPS subunits for clinical outcome. Expression levels of COPS subunits were significantly upregulated in HCC tissues, which predicted shorter overall survival (OS). Further, Cox regression analysis identified COPS5, COPS7B, and COPS9 as independent prognostic biomarkers for OS. High mutation rates were also found in COPS subunits. Functional network analysis indicated that COPS and neighboring genes regulate \'protein neddylation\', \'protein deneddylation\', and \'protein ubiquitination\'. The COPS PPI included strong interactions with p53, CUL1/2/3/4, and JUN. Moreover, the correlations between COPS subunit expression levels and tumor immune cell infiltration rates were examined using TIMER, TISIDB, ssGSEA, and ESTIMATE packages. COPS subunits expression levels were positively correlated with specific tumor immune cell infiltration rates, immunoregulator expression levels, and microsatellite instability in HCC. Finally, knockout of COPS6 and COPS9 in HCC cells reduced while overexpression enhanced proliferation rate and metastasis capacity. Our study revealed that COPS potential biomarker for unfavorable HCC prognosis and indicators of immune infiltration, tumorigenicity, and metastasis.

G protein pathway suppressor 1 (GPS1) is involved in the development of many diseases including tumors, but its specific regulatory mechanism in breast cancer is not clear. The goal of the present study was to explore the biological effects and underlying mechanism of GPS1 in breast cancer. Public databases were used to analyze GPS1 expression and the relationship with clinicopathological characteristics and prognosis of breast cancer patients, combined with in vitro experiments to analyze the mechanism of action and immune relevance of GPS1 in breast cancer. Data analysis showed that the expression of GPS1 in breast cancer tissues was significantly higher than that in paracancerous tissues (p < 0.001), and the receiver operating curve (ROC) revealed a higher diagnostic efficiency (AUC = 0.832). Survival analyses indicated that patients with high GPS1 expression made the prognosis worse in Luminal B, low to intermediate-grade breast cancers. Enrichment analysis showed that GPS1 was involved in the formation of ribonucleoprotein complexes, which dynamically altered the fate of RNA; it could also enhance the responsiveness of the Wnt pathway by interacting with WBP2. In addition, GPS1 expression was closely related to the immune microenvironment. GPS1 knockdown inhibits the proliferation, invasion and migration of MCF7 and MDA-MB-231 cells in vitro. This study suggests that the upregulation of GPS1 is associated with the malignant biological behavior and prognosis of breast cancer and may promote cancer progression. The correlation between GPS1 and the immune microenvironment suggests that it may be a potential target for immunotherapy.

Functions of the SKP1-CUL1-F box (SCF) ubiquitin E3 ligases are essential in plants. The F box proteins (FBPs) are substrate receptors that recruit substrates and assemble an active SCF complex, but the regulatory mechanism underlying the FBPs binding to CUL1 to activate the SCF cycle is not fully understood. We show that Arabidopsis csn1-10 is defective in SCFEBF1-mediated PIF3 degradation during de-etiolation, due to impaired association of EBF1 with CUL1 in csn1-10. EBF1 preferentially associates with un-neddylated CUL1 that is deficient in csn1-10 and the EBF1-CUL1 binding is rescued by the neddylation inhibitor MLN4924. Furthermore, we identify a subset of FBPs with impaired binding to CUL1 in csn1-10, indicating their assembly to form SCF complexes may depend on COP9 signalosome (CSN)-mediated deneddylation of CUL1. This study reports that a key role of CSN-mediated CULLIN deneddylation is to gate the binding of the FBP-substrate module to CUL1, thus initiating the SCF cycle of substrate ubiquitination.

Transmission of many plant viruses relies on phloem-feeding insect vectors. However, how plant viruses directly modulate insect behavior is largely unknown. Barley yellow striate mosaic virus (BYSMV) is transmitted by the small brown planthopper (SBPH, Laodelphax striatellus). Here, we show that BYSMV infects the central nervous system (CNS) of SBPHs, induces insect hyperactivity, and prolongs phloem feeding duration. The BYSMV accessory protein P6 interacts with the COP9 signalosome subunit 5 (LsCSN5) of SBPHs and suppresses LsCSN5-regulated de-neddylation from the Cullin 1 (CUL1), hereby inhibiting CUL1-based E3 ligases-mediated degradation of the circadian clock protein Timeless (TIM). Thus, virus infection or knockdown of LsCSN5 compromises TIM oscillation and induces high insect locomotor activity for transmission. Additionally, expression of BYSMV P6 in the CNS of transgenic Drosophila melanogaster disturbs circadian rhythm and induces high locomotor activity. Together, our results suggest the molecular mechanisms whereby BYSMV modulates locomotor activity of insect vectors for transmission.

The constitutive photomorphogenesis 9 (COP9) signalosome (CSN) is a deNEDDylase controlling ubiquitination activity of cullin-RING-E3 ligases (CRLs) and thus the levels of key cellular proteins. While the CSN and its catalytic subunit CSN5 have been extensively studied in cancer, its role in inflammatory and neurological diseases is less understood. Following verification that CSN5 is expressed in mouse and human brain, here we studied the role of the CSN in neuroinflammation and ischemic neuronal damage employing models of relevant brain-resident cell types, an ex vivo organotypic brain slice culture model, and the CRL NEDDylation state-modifying drugs MLN4924 and CSN5i-3, which mimic and inhibit, respectively, CSN5 deNEDDylase activity. Untargeted mass spectrometry-based proteomics revealed that MLN4924 and CSN5i-3 substantially alter the microglial proteome, including inflammation-related proteins. Applying these drugs and mimicking microglial and endothelial inflammation as well as ischemic neuronal stress by TNF and oxygen-glucose-deprivation/reoxygenation (OGD/RO) treatment, respectively, we could link CSN5/CSN-mediated cullin deNEDDylation to reduction of microglial inflammation, attenuated cerebral endothelial inflammation, improved barrier integrity, as well as protection from ischemic stress-induced neuronal cell death. Specifically, MLN4924 reduced phagocytic activity, motility, and inflammatory cytokine expression of microglial cells, and this was linked to inhibition of inflammation-induced NF-κB and Akt signaling. Inversely, Csn5 knockdown and CSN5i-3 increased NF-κB signaling. Moreover, MLN4924 abrogated TNF-induced NF-κB signaling in cerebral microvascular endothelial cells (hCMECs) and rescued hCMEC monolayers from OGD/RO-triggered barrier leakage, while CSN5i-3 exacerbated permeability. In an ex vivo organotypic brain slice model of ischemia/reperfusion stress, MLN4924 protected from neuronal death, while CSN5i-3 impaired neuronal survival. Neuronal damage was attributable to microglial activation and inflammatory cytokines, as indicated by microglial shape tracking and TNF-blocking experiments. Our results indicate a protective role of the CSN in neuroinflammation via brain-resident cell types involved in ischemic brain disease and implicate CSN activity-mimicking deNEDDylating drugs as potential therapeutics.

Many studies have provided valuable information about genomic and transcriptomic changes that occur in colorectal cancer. However, protein abundance cannot be reliably predicted by DNA alteration or mRNA expression, which can be partially attributed to posttranscriptional and/or translational regulation of gene expression. In this study, we identified increased translational efficiency (TE) as a hallmark of colorectal cancer by evaluating the transcriptomic and proteomic features of patients with colorectal cancer, along with comparative transcriptomic and ribosome-protected mRNA analysis in colon epithelial cells and colon cancer cells. COP9 signalosome subunit 7B (COPS7B) was among the key genes that consistently showed both significant TE increase and protein elevation without transcriptional alteration in colorectal cancer. Insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) enhanced the TE of COPS7B mRNA to promote colorectal cancer growth and metastasis. COPS7B was found to be a component of the ribo-interactome that interacted with ribosomes to facilitate ribosome biogenesis and mRNA translation initiation. Collectively, this study revealed the proteomic features of colorectal cancer and highlighted elevated mRNA translation as a hallmark of colorectal cancer. The identification of the IGF2BP3-COPS7B axis underlying the increased protein synthesis rate in colorectal cancer provided a promising therapeutic target to treat this aggressive disease.
Increased expression of COPS7B mediated by IGF2BP3 elevates the translational efficiency of genes enriched in mRNA translation and ribosome biogenesis pathways, promoting protein synthesis and driving progression in colorectal cancer.

Colorectal cancer (CRC) is a serious threat to human health, and its underlying mechanisms remain to be further explored. Aldolase A (ALDOA) has received increasing attention for its reported association with multiple cancers, but the role and mechanisms of ALDOA in CRC are still unclear. In the current study, high expression levels and enzymatic activity of ALDOA were detected in CRC tissues and cell lines, indicating the clinical significance of ALDOA in human CRC. In addition, silencing ALDOA significantly impaired the proliferation and metastasis of CRC cells in vitro and in vivo. Mechanistically, immunoprecipitation assays and mass spectrometry analysis identified the binding protein COPS6 of ALDOA. Furthermore, the promoting effects of upregulated ALDOA on CRC cell proliferation and metastasis were inhibited by COPS6 depletion, demonstrating COPS6 was required for ALDOA in mediating CRC progress. Moreover, the epithelial-mesenchymal transition (EMT) program and MAPK signaling pathway were found to be activated by ALDOA overexpression as well. In summary, our findings suggested that ALDOA facilitated the proliferation and metastasis of CRC by binding and regulating COPS6, inducing EMT, and activating the mitogen-activated protein kinase (MAPK) signaling pathway. The present study provided evidence for ALDOA as a promising potential biomarker for CRC.