Grb2 Research Articles

The role of GRB2 in diabetes, diabetes complications and related disorders.

Growth factor receptor-bound protein 2 (GRB2) is a key adaptor protein involved in multiple signalling pathways, and its dysregulation is associated with various diseases. Type 2 diabetes is a systemic condition characterized by insulin resistance and impaired β-cell function. The complications of diabetes significantly reduce life expectancy and quality of life, imposing a substantial burden on society. However, the role of GRB2 in diabetes and associated complications is largely unknown. Emerging evidence suggests that GRB2 plays a crucial role in insulin resistance, inflammation, immune activation and the regulation of cellular processes such as cell proliferation, growth, metabolism, angiogenesis, apoptosis and differentiation. Dysregulation of GRB2-mediated pathways contributes to the progression of diabetic neuropathy, cognitive dysfunction, nephropathy, retinopathy and related disorders. This review provides a comprehensive overview of the current understanding of the role of GRB2 in diabetes, diabetes complications and related disorders, alongside recent advances in the development of GRB2-targeted therapies. Elucidating the complex role of GRB2 in these disorders provides valuable insights into potential therapeutic strategies targeting GRB2-mediated pathways.

Shc1 cooperates with Frs2 and Shp2 to recruit Grb2 in FGF-induced lens development.

Fibroblast growth factor (FGF) signaling elicits multiple downstream pathways, most notably the Ras/MAPK cascade facilitated by the adaptor protein Grb2. However, the mechanism by which Grb2 is recruited to the FGF signaling complex remains unresolved. Here we showed that genetic ablation of FGF signaling prevented lens induction by disrupting transcriptional regulation and actin cytoskeletal arrangements, which could be reproduced by deleting the juxtamembrane region of the FGF receptor and rescued by Kras activation. Conversely, mutations affecting the Frs2-binding site on the FGF receptor or the deletion of Frs2 and Shp2 primarily impact later stages of lens vesicle development involving lens fiber cell differentiation. Our study further revealed that the loss of Grb2 abolished MAPK signaling, resulting in a profound arrest of lens development. However, disrupting the Grb2 binding site on Shp2 or abrogating Shp2 phosphatase activity only modestly influenced FGF signaling, whereas mutating the presumed Shp2 dephosphorylation site on Grb2 did not impede MAPK signaling in lens development, indicating that Shp2 is only partially responsible for Grb2 recruitment. In contrast, we observed that FGF signaling is required for the phosphorylation of the Grb2-binding sites on Shc1 and the deletion of Shc1 exacerbates the lens vesicle defect caused by Frs2 and Shp2 deletion. These results reveal that Shc1 collaborates with Frs2 and Shp2 to target Grb2 in FGF signaling.

The mechanism of L1 cell adhesion molecule interacting with protein tyrosine kinase 2 to regulate the focal adhesion kinase–growth factor receptor-bound protein 2–son of sevenless–rat sarcoma pathway in the identification and treatment of type I high-risk endometrial cancer

Objective: The objective of this study was to investigate how L1 cell adhesion molecule (L1CAM) interacting with protein tyrosine kinase 2 (PTK2) affects endometrial cancer (EC) progression and determine its association with the focal adhesion kinase (FAK)–growth factor receptor-bound protein 2 (GRB2)–son of sevenless (SOS)–rat sarcoma (RAS) pathway. EC is a female cancer of major concern in the world, and its incidence has increased rapidly in recent years. L1CAM is considered a reliable marker of poor prognosis in patients with EC. Material and Methods: A single-center and prospective study was conducted using data from the Cancer Genome Atlas and samples from normal and EC tissues to explore the differential expression of L1CAM. Additional experimental models included human immortalized endometrial epithelium cells (hEECs) and EC cell lines such as KLE, RL95-2, and Ishikawa. L1CAM expression was regulated using lentiviruses designed for either overexpression or interference, and PTK2/focal adhesion kinase (FAK) signaling was inhibited with PF431396. Transfected KLE cells were injected into mice, and tumor growth was monitored over 14 days. Cellular proliferation and survival were assessed using cell counting kit, colony formation, and terminal deoxynucleotidyl transferase-mediated 2’-deoxyuridine 5’-triphosphate (dUTP) nick-end labeling assays. Metastatic behavior was evaluated through Transwell assays for cell migration and invasion. The expression levels of matrix metallopeptidase (MMP) 2 and MMP9 were determined by Western blot. In addition, the activation of the FAK–GRB2–SOS–RAS pathway was examined by assessing the protein levels of FAK, GRB2, SOS, and RAS. Results: There was a significant difference in L1CAM expression between EC tumor tissues and normal tissues, and L1CAM messenger RNA (1.85-fold) and L1CAM protein (2.59-fold) were significantly more expressed in EC tissues (P < 0.01) than in normal tissues. The tumor growth of L1CAM overexpressing EC cells was faster than that of negative control EC cells (6.43 fold; P < 0.001). L1CAM promoted the expression of FAK (1.43-2.72-fold; P < 0.001); enhanced EC cell proliferation (P < 0.01), survival and motility (P < 0.001), migration (P < 0.001), and invasion (P < 0.001); and activated the FAK–GRB2–SOS–RAS pathway, all of which were reversed when FAK expression was not upregulated (P < 0.001). Conclusion: By upregulating PTK2 and its encoded protein FAK, L1CAM was found to promote tumor progression and increase the activation of the FAK–GRB2–SOS–RAS pathway. These findings establish L1CAM and PTK2 as reference genes for poor prognostic prediction in EC and as targets for EC therapy, providing a valuable basis for distinguishing between benign and malignant endometrial conditions and justifying the necessity of targeted therapeutic approaches.

Association of the rs9896052 Polymorphism Upstream of GRB2 with Proliferative Diabetic Retinopathy in Patients with Less than 10 Years of Diabetes

Growth factor receptor-bound protein 2 (GRB2) is a negative regulator of insulin signaling and a positive regulator of angiogenesis. Its expression is increased in a mouse model of retinal neovascularization and in patients with type 2 diabetes mellitus (T2DM). This case–control study aimed to investigate the association between the rs9896052 polymorphism (A>C) upstream of GRB2 and proliferative diabetic retinopathy (PDR) in patients with T2DM from Southern Brazil, taking into consideration self-reported skin color (white or non-white) and the known duration of diabetes (<10 years or ≥10 years). Genotypes were determined by real-time PCR in 838 patients with T2DM (284 cases with PDR and 554 controls without DR). In the total study group and in the analysis stratified by skin color, the genotype and allele frequencies were similar between cases and controls. However, among patients with less than 10 years of diabetes, the C allele was more frequent in cases than in controls (63.3% versus 51.8%, p = 0.032), and the CC genotype was independently associated with an increased risk of PDR (adjusted OR = 2.82, 95% CI 1.17–6.75). In conclusion, our findings support the hypothesis that the rs9896052 polymorphism near GRB2 is associated with PDR in Brazilian patients with T2DM.

SIK2: A Novel Negative Feedback Regulator of FGF2 Signaling.

A wide range of cells respond to fibroblast growth factor 2 (FGF2) by proliferation via activation of the Ras/ERK1/2 pathway. In this study, the potential involvement of salt inducible kinase SIK2)in this cascade within retinal Müller glia is explored. It is found that SIK2 phosphorylation status and activity are modulated in an FGF2-dependent manner, possibly via ERK1/2. With SIK2 downregulation, enhanced ERK1/2 activation with delayed attenuation and increased cell proliferation is observed, while SIK2 overexpression hampers FGF2-dependent ERK1/2 activation. In vitro kinase and site-directed mutagenesis studies indicate that SIK2 targets the pathway element GRB2-associated-binding protein 1 (Gab1) on Ser266. This phosphorylation event weakens Gab1 interactions with its partners growth factor receptor-bound protein 2 (Grb2) and Src homology region 2 domain containing phosphatase 2 (Shp2). Collectively, these results suggest that during FGF2-dependent proliferation process ERK1/2-mediated activation of SIK2 targets Gab1, resulting in downregulation of the Ras/ERK1/2 cascade in a feedback loop.

Grb2 Y160F mutant mimics the wild-type monomeric state dynamics and the monomer-dimer equilibrium

The Growth factor receptor-bound protein 2 (Grb2) participates in early signaling complexes and regulates tyrosine kinase-mediated signal transduction through a monomer-dimer equilibrium. Grb2 dimeric state inhibits signal transduction whereas the monomer promotes signaling downstream. Since Grb2 dimer KD is ∼0.8 μM, studies focused on the monomer are still challenging and require mutations or interaction with phosphotyrosine peptides. However, these mutants were never characterized considering their effects on protein structure and dynamics in solution. Here, we present the biophysical characterization of Grb2Y160F, the first Grb2 mutant to induce protein monomerization without disrupting its native behavior in solution due to net charge modifications or interaction with peptides. We also identified that Grb2Y160F exists in a monomer-dimer equilibrium. Grb2Y160F ability to dimerize implies that different dimerization interfaces might regulate signaling pathways in distinct ways and raises an important question about the role of the Y160 residue in other dimerization interfaces.

Ginsenoside Rg3 Restores Mitochondrial Cardiolipin Homeostasis via GRB2 to Prevent Parkinson's Disease.

Regulating cardiolipin to maintain mitochondrial homeostasis is a promising strategy for addressing Parkinson's disease (PD). Through a comprehensive screening and validation process involving multiplemodels, ginsenoside Rg3 (Rg3) as a compound capable of enhancing cardiolipin levels is identified. This augmentation in cardiolipin levels fosters mitochondrial homeostasis by bolstering mitochondrial unfolded protein response, promoting mitophagy, and enhancing mitochondrial oxidative phosphorylation. Consequently, this cascade enhances the survival of tyrosine hydroxylase positive (TH+) dopaminergic neurons, leading to an amelioration in motor performance within PD mouse models. Using limited proteolysis-small-molecule mapping combined with molecular docking analysis, it has confirmed Growth Factor Receptor-Bound Protein 2 (GRB2) as a molecular target for Rg3. Furthermore, these investigations reveal that Rg3 facilitates the interaction between GRB2 and TRKA (Neurotrophic Tyrosine Kinase, Receptor, Type 1), thus promotes EVI1 (Ecotropic Virus Integration Site 1 Protein Homolog) phosphorylation by ERK, subsequently increases CRLS1 (Cardiolipin Synthase 1) gene expression and boosts cardiolipin synthesis. The absence of GRB2 or CRLS1 significantly attenuates the beneficial effects of Rg3 on PD symptoms. Finally, Tenofovir Disoproxil Fumarate (TDF) that also promotes the binding between GRB2 and TRKA is further identified. The identified compounds, Rg3 and TDF, exhibit promising potential for the prevention of PD by bolstering cardiolipin expression and reinstating mitochondrial homeostasis.

GRB7 Plays a Vital Role in Promoting the Progression and Mediating Immune Evasion of Ovarian Cancer.

Despite breakthroughs in treatment, ovarian cancer (OC) remains one of the most lethal gynecological malignancies, with an increasing age-standardized mortality rate. This underscores an urgent need for novel biomarkers and therapeutic targets. Although growth factor receptor-bound protein 7 (GRB7) is implicated in cell signaling and tumorigenesis, its expression pattern and clinical implications in OC remain poorly characterized. To systematically investigate GRB7's expression in OC, our study utilized extensive datasets from TCGA, GTEx, CCLE, and GEO. The prognostic significance of GRB7 was evaluated by means of Kaplan-Meier and Cox regression analyses. Using a correlation analysis and gene set enrichment analysis, relationships between GRB7's expression and gene networks, immune cell infiltration and immunotherapy response were investigated. In vitro experiments were conducted to confirm GRB7's function in the biology of OC. Compared to normal tissues, OC tissues exhibited a substantial upregulation of GRB7. Reduced overall survival, disease-specific survival, and disease-free interval were all connected with high GRB7 mRNA levels. The network study demonstrated that GRB7 is involved in pathways relevant to the course of OC and has a positive connection with several key driver genes. Notably, GRB7's expression was linked to the infiltration of M2 macrophage and altered response to immunotherapy. Data from single-cell RNA sequencing data across multiple cancer types indicated GRB7's predominant expression in malignant cells. Moreover, OC cells with GRB7 deletion showed decreased proliferation and migration, as well as increased susceptibility to T cell-mediated cytotoxicity. With respect to OC, our results validated GRB7 as a viable prognostic biomarker and a promising therapeutic target, providing information about its function in tumorigenesis and immune modulation. GRB7's preferential expression in malignant cells highlights its significance in the biology of cancer and bolsters the possibility that it could be useful in enhancing the effectiveness of immunotherapy.

TCF12-regulated GRB7 facilitates the HER2+ breast cancer progression by activating Notch1 signaling pathway

BackgroundHuman epidermal growth factor receptor 2-positive (HER2+) breast cancer (BC), which accounts for approximately one-fifth of all BCs, are highly invasive with a high rate of recurrence and a poor prognosis. Several studies have shown that growth factor receptor-bound protein 7 (GRB7) might be a potential therapeutic target for tumor diagnosis and prognosis. Nevertheless, the role of GRB7 in HER2+ BC and its underlying mechanisms have not been fully elucidated. The aim of this study was to investigate the biological function and regulatory mechanism of GRB7 in HER2+ BC.MethodsBioinformatics analysis was performed using the TCGA, GEO and CancerSEA databases to evaluate the clinical significance of GRB7. RT quantitative PCR, western blot and immunofluorescence were conducted to assess the expression of GRB7 in BC cell lines and tissues. MTT, EdU, colony formation, wound healing, transwell, and xenograft assays were adopted to explore the biological function of GRB7 in HER2+ BC. RNA sequencing was performed to analyze the signaling pathways associated with GRB7 in SK-BR-3 cells after the cells were transfected with GRB7 siRNA. Chromatin immunoprecipitation analysis (ChIP) and luciferase reporter assay were employed to elucidate the potential molecular regulatory mechanisms of GRB7 in HER2+ BC.ResultsGRB7 was markedly upregulated and associated with poor prognosis in BC, especially in HER2+ BC. Overexpression of GRB7 increased the proliferation, migration, invasion, and colony formation of HER2+ BC cells, while depletion of GRB7 had the opposite effects in HER2+ BC cells and inhibited xenograft growth. ChIP-PCR and luciferase reporter assay revealed that TCF12 directly bound to the promoter of the GRB7 gene to promote its transcription. GRB7 facilitated HER2+ BC epithelial-mesenchymal transition (EMT) progression by interacting with Notch1 to activate Wnt/β-catenin pathways and other signaling (i.e., AKT, ERK). Moreover, forced GRB7 overexpression activated Wnt/β-catenin to promote EMT progression, and partially rescued the inhibition of HER2+ BC proliferation, migration and invasion induced by TCF12 silencing.ConclusionsOur work elucidates the oncogenic role of GRB7 in HER2+ BC, which could serve as a prognostic indicator and promising therapeutic target.

Porcine deltacoronavirus nucleocapsid protein interacts with the Grb2 through its proline-rich motifs to induce activation of the Raf-MEK-ERK signal pathway and promote virus replication.

Porcine deltacoronavirus (PDCoV), an enteropathogenic coronavirus, causes severe watery diarrhoea, dehydration and high mortality in piglets, which has the potential for cross-species transmission in recent years. Growth factor receptor-bound protein 2 (Grb2) is a bridging protein that can couple cell surface receptors with intracellular signal transduction events. Here, we investigated the reciprocal regulation between Grb2 and PDCoV. It is found that Grb2 regulates PDCoV infection and promotes IFN-β production through activating Raf/MEK/ERK/STAT3 pathway signalling in PDCoV-infected swine testis cells to suppress viral replication. PDCoV N is capable of interacting with Grb2. The proline-rich motifs in the N- or C-terminal region of PDCoV N were critical for the interaction between PDCoV-N and Grb2. Except for Deltacoronavirus PDCoV N, the Alphacoronavirus PEDV N protein could interact with Grb2 and affect the regulation of PEDV replication, while the N protein of Betacoronavirus PHEV and Gammacoronavirus AIBV could not interact with Grb2. PDCoV N promotes Grb2 degradation by K48- and K63-linked ubiquitin-proteasome pathways. Overexpression of PDCoV N impaired the Grb2-mediated activated effect on the Raf/MEK/ERK/STAT3 signal pathway. Thus, our study reveals a novel mechanism of how host protein Grb2 protein regulates viral replication and how PDCoV N escaped natural immunity by interacting with Grb2.

Mechanism of Paeoniae Radix Rubra and Aconiti Lateralis Radix Praeparata herbal pair in promoting hepatocellular regeneration in chronic acute liver failure based on HGF/PI3K/Akt signaling axis

Based on the hepatocyte growth factor(HGF)/phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt) signaling axis, this study investigated the therapeutic effect of Paeoniae Radix Rubra and Aconiti Lateralis Radix Praeparata(PRR-ALRP) her-bal pair on acute-on-chronic liver failure(ACLF) rats and its impact on hepatocellular regeneration. The rat model of ACLF was constructed by subcutaneous and tail vein injection of bovine serum albumin combined with intraperitoneal injection of lipopolysaccharides(LPS)+D-galactosamine(D-GalN). The rats were divided into normal control(NC) group, model(vehicle) group, PRR-ALRP(5.85 g·kg~(-1)) group, and hepatocyte growth factor granules(HGFG, 4.05 g·kg~(-1)) group. Hematoxylin-eosin(HE) staining was used to observe pathological changes in rat liver tissues. Serum alanine aminotransferase(ALT), aspartate transaminase(AST), and total bilirubin(TBIL) were detected using an automatic biochemical analyzer. The levels of interleukin-1β(IL-1β) and tumor necrosis factor-α(TNF-α) inflammatory factors were detected by ELISA. Immunofluorescence staining was used to detect the positive expression of proliferating cell nuclear antigen(PCNA), antigen identified by monoclonal antibody(Ki67), and cell cycle protein B1(CyclinB1). Real-time fluorescence-based quantitative polymerase chain reaction(RT-qPCR) and Western blot were used to detect the mRNA and protein expression levels of HGF, growth factor receptor-bound protein 1(Gab1), PI3K, Akt, phosphorylated PI3K(p-PI3K), and phosphorylated Akt(p-Akt). The results showed that compared with the vehicle group, the PRR-ALRP group had reduced liver tissue pathological scores, improved liver function, and reduced inflammatory response, with enhanced PCNA, Ki67, and CyclinB1 fluorescence expression. Furthermore, compared with the model group, the PRR-ALRP group showed upregulated expression of HGF and Gab1 proteins, as well as activation of PI3K and Akt phosphorylation. These findings suggest that PRR-ALRP herbal pair exerts anti-liver failure effects by alleviating hepatocyte inflammatory damage and promoting hepatocellular regeneration, and its specific regulatory mechanism may be related to the activation of the HGF/PI3K/Akt signaling pathway.

Characterization of latently infected EBV+ antibody-secreting B cells isolated from ovarian tumors and malignant ascites.

Intra-tumoral B cells mediate a plethora of immune effector mechanisms with key roles in anti-tumor immunity and serve as positive prognostic indicators in a variety of solid tumor types, including epithelial ovarian cancer (EOC). Several aspects of intra-tumoral B cells remain unclear, such as their state of activation, antigenic repertoires, and capacity to mature into plasma cells. B lymphocytes were isolated from primary EOC tissue and malignant ascites and were maintained in cell culture medium. The stably maintained cell lines were profiled with flow cytometry and B cell receptor sequencing. Secreted antibodies were tested with a human proteome array comprising more than 21,000 proteins, followed by ELISA for validation. Originating tumor samples were used for spatial profiling with chip cytometry. Antibody-secreting B lymphocytes were isolated from the ovarian tumor microenvironment (TME) of four different EOC patients. The highly clonal cell populations underwent spontaneous immortalization in vitro, were stably maintained in an antibody-secreting state, and showed presence of Epstein-Barr viral (EBV) proteins. All originating tumors had high frequency of tumor-infiltrating B cells, present as lymphoid aggregates, or tertiary lymphoid structures. The antigens recognized by three of the four cell lines are coil-coil domain containing protein 155 (CCDC155), growth factor receptor-bound protein 2 (GRB2), and pyruvate dehydrogenase phosphatase2 (PDP2), respectively. Anti-CCDC155 circulating IgG antibodies were detected in 9 of 20 (45%) of EOC patients' sera. Tissue analyses with multiparameter chip cytometry shows that the antibodies secreted by these novel human B cell lines engage their cognate antigens on tumor cells. These studies demonstrate that within the tumor-infiltrating lymphocyte population in EOC resides a low frequency population of antibody-secreting B cells that have been naturally exposed to EBV. Once stably maintained, these novel cell lines offer unique opportunities for future studies on intratumor B cell biology and new target antigen recognition, and for studies on EBV latency and/or viral reactivation in the TME of non-EBV related solid tumors such as the EOC.

Allosteric regulation of the tyrosine phosphatase PTP1B by a protein-protein interaction.

The rapid identification of protein-protein interactions has been significantly enabled by mass spectrometry (MS) proteomics-based methods, including affinity purification-MS, crosslinking-MS, and proximity-labeling proteomics. While these methods can reveal networks of interacting proteins, they cannot reveal how specific protein-protein interactions alter cell signaling or protein function. For instance, when two proteins interact, there can be emergent signaling processes driven purely by the individual activities of those proteins being co-localized. Alternatively, protein-protein interactions can allosterically regulate function, enhancing or suppressing activity in response to binding. In this work, we investigate the interaction between the tyrosine phosphatase PTP1B and the adaptor protein Grb2, which have been annotated as binding partners in a number of proteomics studies. This interaction has been postulated to co-localize PTP1B with its substrate IRS-1 by forming a ternary complex, thereby enhancing the dephosphorylation of IRS-1 to suppress insulin signaling. Here, we report that Grb2 binding to PTP1B also allosterically enhances PTP1B catalytic activity. We show that this interaction is dependent on the proline-rich region of PTP1B, which interacts with the C-terminal SH3 domain of Grb2. Using NMR spectroscopy and hydrogen-deuterium exchange mass spectrometry (HDX-MS) we show that Grb2 binding alters PTP1B structure and/or dynamics. Finally, we use MS proteomics to identify other interactors of the PTP1B proline-rich region that may also regulate PTP1B function similarly to Grb2. This work presents one of the first examples of a protein allosterically regulating the enzymatic activity of PTP1B and lays the foundation for discovering new mechanisms of PTP1B regulation in cell signaling.

Genetic variation near GRB10 associated with bone growth and osteosarcoma risk in canine and human populations

BackgroundCanine and human osteosarcoma are similar in clinical presentation and tumor genomics. Giant breed dogs experience elevated osteosarcoma incidence, and taller stature remains a consistent risk factor for human osteosarcoma. Whether evolutionarily conserved genes contribute to both human and canine osteosarcoma predisposition merits evaluation. MethodsA multi-center sample of childhood osteosarcoma patients and controls underwent genome-wide genotyping and imputation. Ancestry-adjusted SNP associations were calculated within each dataset using logistic regression, then meta-analyzed across the three datasets, totaling 1091 patients and 3026 controls. Ten regions previously associated with canine osteosarcoma risk were mapped to the human genome, spanning ∼6 Mb. We prioritized association testing of 5985 human SNPs mapping to candidate osteosarcoma risk regions detected in Irish wolfhounds, the largest dog breed studied. Secondary analyses explored 6289 additional human SNPs mapping to candidate osteosarcoma risk regions identified in Rottweilers and greyhounds. ResultsFourteen SNPs were associated with human osteosarcoma risk after adjustment for multiple comparisons, all within a 42 kb region of human Chromosome 7p12.1. The lead variant was rs17454681 (OR=1.25, 95 %CI: 1.12–1.39; P=4.1×10−5), and independent risk variants were not observed in conditional analyses. While the associated region spanned 2.1 Mb and contained eight genes in Irish wolfhounds, associations were localized to a 50-fold smaller region of the human genome and strongly implicate GRB10 (growth factor receptor-bound protein 10) in canine and human osteosarcoma predisposition. PheWAS analysis in UK Biobank data identified noteworthy associations of the rs17454681 risk allele with varied measures of height and pubertal timing. ConclusionsOur comparative oncology analysis identified a novel human osteosarcoma risk allele near GRB10, a growth inhibitor that suppresses activated receptor tyrosine kinases including IGF1R, PDGFRB, and EGFR. Epidemiologists may benefit from leveraging cross-species comparisons to identify haplotypes in highly susceptible but genetically homogenous populations of domesticated animals, then fine-mapping these associations in diverse human populations.

The novel candidate gene Grb10 regulates the growth performance of Guizhou white goats

Growth factor receptor binding protein 10 (Grb10) regulates muscle growth but its function in goats is not well studied. This study examined the relationship between Grb10 gene polymorphism and growth traits in Guizhou white goats. Further, the effect of promoter polymorphism on Grb10 transcription was analyzed via a dual-luciferase assay. Quantitative reverse transcription-polymerase chain reaction analysis showed that the expression level of the Grb10 gene was the highest in the longissimus dorsi muscle (P < 0.01) and the lowest in the spleen. Moreover, sequencing results showed that the Grb10 gene had five single nucleotide polymorphisms. The association analysis showed that g.–246 C > T, g.72323 T > C, and g.178634 A > G loci were significantly associated with growth traits (P < 0.05). Linkage disequilibrium analysis of each locus showed that g.72323 T > C and g.72814 T > A loci had the strongest linkage (r2 = 0.482, D' = 0.73). Furthermore, according to an analysis conducted using TFDB4 software, it was predicted that a mutation in the promoter region of the g.–246 C > T locus resulted in the absence of four transcriptional regulatory factors. The results of dual-luciferase reporter assay further demonstrated that mutation of the g.–246 C > T locus reduced the transcriptional activity of the promoter region of the Grb10 gene. These findings suggest that Grb10 gene polymorphism could affect growth traits in goats.

Identification of differentially expressed autophagy-related genes in cases of intracranial aneurysm: Bioinformatics analysis

ObjectiveRecent research indicates that autophagy is essential for the rupture of intracranial aneurysm (IA). This study aimed to examine and validate potential autophagy-related genes (ARGs) in cases of IA using bioinformatics analysis. MethodsTwo expression profiles (GSE54083 and GSE75436) were obtained from the Gene Expression Omnibus database. Differentially expressed ARGs (DEARGs) in cases of IA were screened using GSE75436, and enrichment analysis and Protein–Protein Interaction (PPI) networks were used to identify the hub genes and related pathways. Furthermore, a novel predictive diagnostic signature for IA based on the hub genes was constructed. The area under the Receiver Operating Characteristic curve (AUC) was used to evaluate the signature performance in GSE75436. ResultsIn total, 75 co-expressed DEARGs were identified in the GSE75436 and GSE54083 dataset (28 upregulated and 47 downregulated genes). Enrichment analysis of DEARGs revealed several enriched terms associated with proteoglycans in cancer and human immunodeficiency virus 1 infection. PPI analysis revealed interactions between these genes. Hub DEARGs included insulin-like growth factor 1, clusters of differentiation 4, cysteine-aspartic acid protease 8, Bcl-2-like protein 11, mouse double mutant 2 homolog, toll-like receptor 4, growth factor receptor-bound protein 2, Jun proto-oncogene, AP-1 transcription factor subunit, hypoxia inducible factor 1 alpha, and erythroblastic oncogene B-2. Notably, the signature showed good performance in distinguishing IA (AUC = 0.87). The sig calibration curves showed good calibration. ConclusionBioinformatic analysis identified 75 potential DEARGs in cases of IA. This study revealed that IA is affected by autophagy, which could explain the pathogenesis of IA and aid in its diagnosis and treatment. However, future research with experimental validation is necessary to identify potential DEARGs in cases of IA.

GRB2 stabilizes RAD51 at reversed replication forks suppressing genomic instability and innate immunity against cancer

Growth factor receptor-bound protein 2 (GRB2) is a cytoplasmic adapter for tyrosine kinase signaling and a nuclear adapter for homology-directed-DNA repair. Here we find nuclear GRB2 protects DNA at stalled replication forks from MRE11-mediated degradation in the BRCA2 replication fork protection axis. Mechanistically, GRB2 binds and inhibits RAD51 ATPase activity to stabilize RAD51 on stalled replication forks. In GRB2-depleted cells, PARP inhibitor (PARPi) treatment releases DNA fragments from stalled forks into the cytoplasm that activate the cGAS–STING pathway to trigger pro-inflammatory cytokine production. Moreover in a syngeneic mouse metastatic ovarian cancer model, GRB2 depletion in the context of PARPi treatment reduced tumor burden and enabled high survival consistent with immune suppression of cancer growth. Collective findings unveil GRB2 function and mechanism for fork protection in the BRCA2-RAD51-MRE11 axis and suggest GRB2 as a potential therapeutic target and an enabling predictive biomarker for patient selection for PARPi and immunotherapy combination.

The binding selectivity of the C-terminal SH3 domain of Grb2, but not its folding pathway, is dictated by its contiguous SH2 domain

The adaptor protein Grb2, or Growth factor receptor bound protein 2, possesses a pivotal role in the transmission of fundamental molecular signals in the cell. Despite lacking enzymatic activity, Grb2 functions as a dynamic assembly platform, orchestrating intracellular signals through its modular structure. This study delves into the energetic communication of Grb2 domains, focusing on the folding and binding properties of the C-SH3 domain linked to its neighboring SH2 domain. Surprisingly, while the folding and stability of C-SH3 remain robust and unaffected by SH2 presence, significant differences emerge in the binding properties when considered within the tandem context compared to isolated C-SH3. Through a double mutant cycle analysis, we highlighted a subset of residues, located at the interface with the SH2 domain and far from the binding site, finely regulating the binding of a peptide mimicking a physiological ligand of the C-SH3 domain. Our results have mechanistic implications about the mechanisms of specificity of the C-SH3 domain, indicating that the presence of the SH2 domain optimizes binding to its physiological target, and emphasizing the general importance of considering supramodular multidomain protein structures to understand the functional intricacies of protein-protein interaction domains.

Suppression of Migration and Invasion by 4-Carbomethoxyl-10-Epigyrosanoldie E from the Cultured Soft Coral Sinularia sandensis through the MAPKs Pathway on Oral Cancer Cells.

The primary reason for cancer-related fatalities is metastasis. The compound 4-carbomethoxyl-10-epigyrosanoldie E, derived from the Sinularia sandensis soft coral species grown in cultures, exhibits properties that counteract inflammation. Moreover, it has been observed to trigger both apoptosis and autophagy within cancerous cells. This research focuses on examining the inhibitory impact of 4-carbomethoxyl-10-epigyrosanoldie E on the migration and invasion processes in Cal-27 and Ca9-22 oral cancer cell lines. To assess how this compound affects cell migration and invasion, the Boyden chamber assay was employed. Furthermore, Western blot analysis was utilized to explore the underlying molecular mechanisms. In a dose-dependent manner, 4-carbomethoxyl-10-epigyrosanoldie E notably decreased the levels of matrix metalloproteinase-2 (MMP-2) and MMP-9, along with urokinase-type plasminogen activator (uPA), in both Cal-27 and Ca9-22 cell lines. Conversely, it elevated the concentrations of tissue inhibitors of metalloproteinases-1 (TIMP-1) and TIMP-2. In addition, the treatment with this compound led to the inhibition of phosphorylation in extracellular signal-regulated kinase (ERK), p38, and c-Jun N-terminal kinase (JNK). It also curtailed the expression of several key proteins including focal adhesion kinase (FAK), protein kinase C (PKC), growth factor receptor-bound protein 2 (GRB2), Rac, Ras, Rho A, mitogen-activated protein kinase kinase kinase 3 (MEKK3), and mitogen-activated protein kinase kinase 7 (MKK7). Furthermore, the expression levels of IQ-domain GTPase-activating protein 1 (IQGAP1) and zonula occludens-1 (ZO-1) were significantly reduced by the compound. The ability of 4-carbomethoxyl-10-epigyrosanoldie E to inhibit the migration and invasion of Cal-27 and Ca9-22 oral cancer cells was observed to be dose dependent. This inhibitory effect is primarily attributed to the suppression of MMP-2 and MMP-9 expression, as well as the downregulation of the mitogen-activated protein kinase (MAPK) signaling pathway.

Circ_0026134 regulates the miR-1270/GRB2 pathway to affect the radiosensitivity of hepatoma cells

Objective: To investigate whether circular RNA 0026134 (circ_0026134) affects the radiosensitivity of hepatoma cells by regulating the miR-1270/growth factor receptor-bound protein 2 (GRB2) pathway. Methods: Real-time quantitative PCR (RT-qPCR) was used to detect the expression levels of circ_0026134, miR-1270, and GRB2 in liver cancer tissues and cells. Bioinformatics analysis, a dual-luciferase gene reporter assay, RT-qPCR, and western blot were used to analyze the targeting relationships between circ_0026134 and miR-1270 and miR-1270 and GRB2. The effects of circ_0026134, miR-1270, and GRB2 expression combined with 6 Gy on the proliferation, invasion, migration, and apoptosis of Huh7 and SK-HEP-1 cells were detected by a cell counting kit, a transwell assay, a scratch assay, and flow cytometry. The tumorigenesis experiment was used to detect the effect of silencing circ_0026134 in nude mice. Measurement data are expressed as the mean ± standard deviation. The independent sample t-test was used for comparison between two groups, and the one-way analysis of variance and SNK-q test were used for comparison between multiple groups. P < 0.05 was considered statistically significant. Results: The expression levels of circ_0026134 and GRB2, Huh7, and SK-HEP-1 cells in liver cancer tissues were significantly increased, while the expression levels of miR-1270 were significantly decreased (P < 0.05). The expression of circ_0026134 in Huh7 and SK-HEP-1 decreased significantly after radiotherapy (P < 0.05). circ_0026134 binds directly to miR-1270 and negatively regulates miR-1270 expression (P < 0.05). miR-1270 binds directly to GRB2 and negatively regulates GRB2 expression (P < 0.05). 6 Gy radiation significantly inhibited the proliferation, migration, and invasion of Huh7 and SK-HEP-1 cells and induced apoptosis (P < 0.05). Silencing circ_0026134 or overexpression of miR-1270 significantly enhanced the anti-proliferation, anti-migration, invasion, and pro-apoptosis effects of 6 Gy treatment on hepatoma cells (P < 0.05). Inhibition of miR-1270 significantly weakened the effects of silencing circ_0026134 combined with 6 Gy radiation on proliferation, migration, invasion, and apoptosis of hepatoma cells (P < 0.05). Overexpression of GRB2 significantly weakened the effects of miR-1270 overexpression combined with 6 Gy radiation on proliferation, migration, invasion, and apoptosis of hepatoma cells (P < 0.05). circ_0026134 knockdown significantly delayed tumor growth in vivo (P < 0.05). Conclusion: Silencing circ_0026134 strengthens radiation treatment's anti-proliferation, anti-migration, invasion, and pro-apoptotic effects in hepatoma cells by negatively regulating the miR-1270/GRB2 pathway, thereby enhancing radiosensitivity.