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Stress granules (SGs) are cytoplasmic biomolecular condensates containing proteins and RNAs in response to stress. Ras-GTPase–activating protein binding protein 1 (G3BP1) is a core SG protein. Caprin-1 and ubiquitin specific peptidase 10 (USP10) interact with G3BP1, facilitating and suppressing SG formation, respectively. The crystal structures of the nuclear transport factor 2-like (NTF2L) domain of G3BP1 in complex with the G3BP1-interacting motif (GIM) of Caprin-1 and USP10 show that both GIMs bind to the same hydrophobic pocket of G3BP1. Moreover, both GIMs suppressed the liquid–liquid phase separation (LLPS) of G3BP1, suggesting that Caprin-1 likely facilitates SG formation via other mechanisms. Thus, we dissected various domains of Caprin-1 and investigated their role in LLPS in vitro and SG formation in cells. The C-terminal domain of Caprin-1 underwent spontaneous LLPS, whereas the N-terminal domain and GIM of Caprin-1 suppressed LLPS of G3BP1. The opposing effect of the N- and C-terminal domains of Caprin-1 on SG formation were demonstrated in cells with or without the endogenous Caprin-1. We propose that the N- and C-terminal domains of Caprin-1 regulate SG formation in a “yin and yang” fashion, mediating the dynamic and reversible assembly of SGs.

Background The abnormal expression of circular RNAs (circRNAs) in uveal melanoma (UM) has been revealed, but the specific underlying molecular mechanism of their association with UM development has not been fully explored. Methods The levels of circ_0119872, G3BP1 and miR-622 in UM cell lines and tissues were determined by quantitative real-time PCR (qRT-PCR) and western blotting assays. In vitro and in vivo assays were performed to investigate the function of circ_0119872 in the tumorigenesis of UM cells. The relationships among circ_0119872, miR-622 and G3BP1 were predicted using bioinformatic tools and verified by RNA-FISH, RNA pull-down and dual-luciferase reporter assays. The effects of circ_0119872 on Wnt/β-catenin and mTOR signalling pathways were determined by gene set enrichment analysis (GSEA) and western blotting. Results We found that circ_0119872 is upregulated in UM cell lines and tissues. Moreover, overexpression of circ_0119872 promotes the malignancy of UM cells, while silencing of circ_0119872 inhibits it. In addition, circ_0119872 can directly interact with miR-622 as a miRNA sponge that regulates the expression of the miR-622 target gene G3BP1 as well as downstream Wnt/β-catenin and mTOR signalling pathways. Conclusions Circ_0119872 may act as an oncogene in UM through a novel circ_0119872/miR-622/G3BP1 axis, activating the Wnt/β-catenin and mTOR signalling pathways, which in turn may provide potential biomarkers and therapeutic targets for the management of UM.

Cells have evolved highly specialized sentinels that detect viral infection and elicit an antiviral response. Among these, the stress-sensing protein kinase R, which is activated by double-stranded RNA, mediates suppression of the host translation machinery as a strategy to limit viral replication. Non-translating mRNAs rapidly condensate by phase separation into cytosolic stress granules, together with numerous RNA-binding proteins and components of signal transduction pathways. Growing evidence suggests that the integrated stress response, and stress granules in particular, contribute to antiviral defense. This review summarizes the current understanding of how stress and innate immune signaling act in concert to mount an effective response against virus infection, with a particular focus on the potential role of stress granules in the coordination of antiviral signaling cascades.

Stress granules (SGs) are non-enveloped structures formed primarily via protein and RNA aggregation under various stress conditions, including hypoxia and viral infection, as well as oxidative, osmotic, and heat-shock stress. SGs assembly is a highly conserved cellular strategy to reduce stress-related damage and promote cell survival. At present, the composition and dynamics of SGs are well understood; however, data on the functions and related mechanisms of SGs are limited. In recent years, SGs have continued to attract attention as emerging players in cancer research. Intriguingly, SGs regulate the biological behavior of tumors by participating in various tumor-associated signaling pathways, including cell proliferation, apoptosis, invasion and metastasis, chemotherapy resistance, radiotherapy resistance, and immune escape. This review discusses the roles and mechanisms of SGs in tumors and suggests novel directions for cancer treatment.

This study investigated whether G3BP1 could regulate ferroptosis in hepatocytes during ALF by affecting the entry of P53 into the nucleus. Promoting G3BP1 expression could inhibit P53 entry by binding to the nuclear localization sequence of P53. The inhibition of SLC7A11 transcription was weakened after blocking of P53 binding to the promoter region of the SLC7A11 gene. The SLC7A11-GSH-GPX4 antiferroptotic pathway was subsequently activated, and the level of ferroptosis in ALF hepatocytes was inhibited.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. Mutations in Cu/Zn superoxide dismutase (SOD1) are responsible for approximately 20 % of the familial ALS cases. ALS-causing SOD1 mutants display a gain-of-toxicity phenotype, but the nature of this toxicity is still not fully understood. The Ras GTPase-activating protein-binding protein G3BP1 plays a critical role in stress granule dynamics. Alterations in the dynamics of stress granules have been reported in several other forms of ALS unrelated to SOD1. To our surprise, the mutant G93A SOD1 transgenic mice exhibited pathological cytoplasmic inclusions that co-localized with G3BP1-positive granules in spinal cord motor neurons. The co-localization was also observed in fibroblast cells derived from familial ALS patient carrying SOD1 mutation L144F. Mutant SOD1, unlike wild-type SOD1, interacted with G3BP1 in an RNA-independent manner. Moreover, the interaction is specific for G3BP1 since mutant SOD1 showed little interaction with four other RNA-binding proteins implicated in ALS. The RNA-binding RRM domain of G3BP1 and two particular phenylalanine residues (F380 and F382) are critical for this interaction. Mutant SOD1 delayed the formation of G3BP1- and TIA1-positive stress granules in response to hyperosmolar shock and arsenite treatment in N2A cells. In summary, the aberrant mutant SOD1–G3BP1 interaction affects stress granule dynamics, suggesting a potential link between pathogenic SOD1 mutations and RNA metabolism alterations in ALS.

Background Metastasis is the key cause of death in ovarian cancer patients. To figure out the biological nature of cancer metastasis is essential for developing effective targeted therapy. Here we investigate how long non-coding RNA (lncRNA) SPOCD1-AS from ovarian cancer extracellular vesicles (EVs) remodel mesothelial cells through a mesothelial-to-mesenchymal transition (MMT) manner and facilitate peritoneal metastasis. Methods EVs purified from ovarian cancer cells and ascites of patients were applied to mesothelial cells. The MMT process of mesothelial cells was assessed by morphology observation, western blot analysis, migration assay and adhesion assay. Altered lncRNAs of EV-treated mesothelial cells were screened by RNA sequencing and identified by qRT-PCR. SPOCD1-AS was overexpressed or silenced by overexpression lentivirus or shRNA, respectively. RNA pull-down and RNA immunoprecipitation assays were conducted to reveal the mechanism by which SPOCD1-AS remodeled mesothelial cells. Interfering peptides were synthesized and applied. Ovarian cancer orthotopic implantation mouse model was established in vivo. Results We found that ovarian cancer-secreted EVs could be taken into recipient mesothelial cells, induce the MMT phenotype and enhance cancer cell adhesion to mesothelial cells. Furthermore, SPOCD1-AS embedded in ovarian cancer-secreted EVs was transmitted to mesothelial cells to induce the MMT process and facilitate peritoneal colonization in vitro and in vivo. SPOCD1-AS induced the MMT process of mesothelial cells via interacting with G3BP1 protein. Additionally, G3BP1 interfering peptide based on the F380/F382 residues was able to block SPOCD1-AS/G3BP1 interaction, inhibit the MMT phenotype of mesothelial cells, and diminish peritoneal metastasis in vivo. Conclusions Our findings elucidate the mechanism associated with EVs and their cargos in ovarian cancer peritoneal metastasis and may provide a potential approach for metastatic ovarian cancer therapeutics.

Previous studies demonstrated that integrin β5 (ITGB5) play an important role in the occurrence and development of various malignant tumors. However, its functional mechanism in gastric cancer (GC) remains obscure. We detected that ITGB5 was overexpressed in GC tissues and its high-level expression was associated with poor survival and advanced stages. Functional assays indicated that overexpression of ITGB5 promotes the proliferation, migration and invasion of GC cells in both vitro and vivo. Mechanistically, we observed a lower variability and invasiveness when GC cells were treated with Defactinib and Saractinib, indicating that activated FAK-Src signaling may lead to an aggressive GC process. Then, we reveal that knockdown of ITGB5 reduces phosphorylation of FAK and Src, without changing total FAK/Src levels. Additionally, ITGB5 interacts with G3BP1 and increases the phosphorylation of FAK and Src. This leads to activation of FAK/Src signaling, which are critical regulators of GC development. Our findings uncover a previously unrecognized mechanism of the ITGB5/G3BP1/FAK/Src axis involved in GC development and the oncogenic potential of ITGB5 in GC, thus providing a potential therapeutic target for advanced GC.

The assembly of stress granules (SGs) is a well-known cellular strategy for reducing stress-related damage and promoting cell survival. SGs have become important players in human health, in addition to their fundamental role in the stress response. The critical role of SGs in cancer cells in formation, progression, and metastasis makes sense. Recent researchers have found that several SG components play a role in tumorigenesis and cancer metastasis via tumor-associated signaling pathways and other mechanisms. Gene-ontology analysis revealed the role of these protein components in the structure of SGs. Involvement in the translation process, regulation of mRNA stability, and action in both the cytoplasm and nucleus are among the main features of SG proteins. The present scoping review aimed to consider all studies on the effect of SGs on cancer formation, proliferation, and metastasis and performed based on a six-stage methodology structure and the PRISMA guideline. A systematic search of seven databases for qualified articles was conducted before July 2021. Publications were screened, and quantitative and qualitative analysis was performed on the extracted data. Go analysis was performed on seventy-one SGs protein components. Remarkably G3BP1, TIA1, TIAR, and YB1 have the largest share among the proteins considered in the studies. Altogether, this scoping review tries to demonstrate and provide a comprehensive summary of the role of SGs in the formation, progression, and metastasis of cancer by reviewing all studies.

Viruses depend on host cellular resources to replicate. Interaction between viral and host proteins is essential for the pathogens to ward off immune responses as well as for virus propagation within the infected cells. While different viruses employ unique strategies to interact with diverse sets of host proteins, the multifunctional RNA-binding protein G3BP1 is one of the common targets for many viruses. G3BP1 controls several key cellular processes, including mRNA stability, translation, and immune responses. G3BP1 also serves as the central hub for the protein–protein and protein–RNA interactions within a class of biomolecular condensates called stress granules (SGs) during stress conditions, including viral infection. Increasing evidence suggests that viruses utilize distinct strategies to modulate G3BP1 function—either by degradation, sequestration, or redistribution—and control the viral life cycle positively and negatively. In this review, we summarize the pro-viral and anti-viral roles of G3BP1 during infection among different viral families.