Search Results (767)

The oncogene KRAS drives tumor growth by activating pathways such as MAPK and PI3K-AKT in a constitutive manner. Although direct KRAS inhibitors exist, they are often limited in clinical use due to therapeutic resistance and toxicity. Therefore, alternative combinatorial therapeutic strategies are urgently needed. This study examined the knockout of five KRAS-related proteins—galectin-3 (GAL3), phosphodiesterase delta (PDEδ), nucleophosmin (NPM1), IQ motif-containing GTPase-activating protein 1 (IQGAP1), and SHOC2—using CRISPR-Cas9 in adenocarcinoma cell lines harboring the KRAS(G12V) oncogenic mutation, as well as in the noncancerous HEK-293 cell line. These proteins act as critical modulators that regulate KRAS activity, cellular localization, and that of its downstream signaling components. We analyzed the downstream activation of ERK and AKT kinases and evaluated subsequent cancer cell proliferation. Knockout of GAL3 and PDEδ was highly effective, significantly reducing MAPK and PI3K-AKT pathway activity and substantially impairing cell proliferation. SHOC2 knockout selectively and potently disrupted MAPK activation, while NPM1 knockout resulted in the complex, reciprocal modulation of the two major pathways. Notably, knocking out IQGAP1 enhanced PI3K–AKT and mTORC2–AKT signaling without affecting the MAPK pathway. These distinct modulatory roles highlight the non-redundant functions of the accessory proteins. In conclusion, our findings establish GAL3 and PDEδ, two KRAS-associated proteins, as promising combinatorial drug targets. Targeting these modulators provides an effective alternative strategy to overcome resistance mechanisms and enhance the clinical utility of existing KRAS inhibitors. Full article

AIG1 (avrRpt2-induced gene 1)-like proteins are a class of GTPases that play crucial roles in plants, functioning both in chloroplast protein import and disease resistance. However, their evolutionary history and the mechanisms driving this functional diversification remain poorly understood. Here, we performed a comprehensive genomic and evolutionary analysis of this gene family across the plant kingdom. We identified 90 AIG1-like genes from 11 sequenced plant species, representing major lineages from green algae to angiosperms. Phylogenetic analysis revealed that plant AIG1-like proteins form three monophyletic lineages corresponding to the Toc34, Toc159, and IAN subfamilies, which originated via two ancient duplications predating the divergence of green algae and land plants. These lineages exhibit dramatically divergent evolutionary patterns. The Toc34 subfamily is evolutionarily conserved, maintaining stable copy numbers and gene structure, indicative of strong functional constraints in its core role in plastid import. In contrast, the Toc159 and IAN subfamilies have undergone dynamic expansion via lineage-specific duplication mechanisms, including segmental duplication and prolific tandem duplication, respectively. Notably, we uncovered a novel mechanism for generating head-to-head tandem duplicates in the IAN subfamily, mediated by recombination between inverted repeats. Our analysis of ancestral gene numbers and gene gain/loss dynamics further highlights that functional diversification was driven by both the acquisition of distinct C-terminal targeting domains (M and TM domains) and profound differences in evolutionary rates and duplication modes among subfamilies. This study provides the first full-scale evolutionary framework for plant AIG1-like genes, establishing that functional specialization is rooted in distinct modes of sequence and genomic evolution. Full article

RhoA (Ras homolog A) is a prominent member of the Rho GTPase family, playing a key role in various cellular processes such as cytoskeletal dynamics, cell migration, and immune responses. However, its function in red swamp crayfish remains unclear. In this study, it is proposed that RhoA may regulate the innate immune response in P. clarkii. The gene was fully characterized as PcRhoA in P. clarkii. The results showed that the open reading frame (ORF) of PcRhoA is 663 bp, encoding a 220-amino acid protein with a conserved Rho domain of 174 amino acids. Phylogenetic analysis placed PcRhoA close to Cherax quadricarinatus RhoA. RT-qPCR analysis revealed high expression levels of the PcRhoA gene in the hepatopancreas, muscle, heart, ovary, and stomach, with lower expression in the blood, intestine, gills, and tentacle gland. Furthermore, PcRhoA mRNA transcript was significantly upregulated in the intestine following LPS and Poly I:C challenges. Knockdown of PcRhoA suppressed the expression of downstream genes in the immune signaling pathway. These results indicate that PcRhoA appears to play a pivotal role in regulating the immune response of crayfish. Full article

Central nervous system (CNS) tumors consist of a diverse set of malignancies that remain clinically challenging due to their biological complexity, high morbidity, and limited responsiveness to current therapies. A growing body of genomic evidence has revealed that dysregulation of the mitogen-activated protein kinase (MAPK) signaling pathway is a recurrent and unifying characteristic across many pediatric and adult CNS tumor entities. Alterations affecting upstream receptor tyrosine kinases (RTKs), RAS GTPases, RAF kinases, and other associated regulators contribute to MAPK signaling pathway hyperactivation, shaping tumor behavior, therapy response and resistance. These aberrations ranging from hotspot mutations such as BRAF V600E and oncogenic fusions like BRAF–KIAA1549 are particularly enriched in gliomas and glioneuronal tumors, highlighting MAPK signaling as a key oncogenic driver. The expanding availability of molecularly targeted compounds, including selective inhibitors of RAF, MEK and ERK, has begun to transform treatment approaches for specific molecular subtypes. However, the clinical benefit of MAPK-directed therapies is frequently limited by restricted blood–brain barrier (BBB) penetration, intratumoral heterogeneity, parallel pathway reactivation, and an immunosuppressive tumor microenvironment (TME). In this review, we synthesize current knowledge on MAPK pathway alterations in CNS tumors and evaluate the therapeutic landscape of MAPK inhibition, with emphasis on approved agents, emerging compounds, combination strategies, and novel drug-delivery technologies. We also discuss mechanisms that undermine treatment efficacy and highlight future directions aimed at integrating MAPK-targeted therapy into precision-based management of brain tumors. Full article

This study evaluated the protective effects of naringin (NG) against intestinal injury in 7-day-old piglets infected with porcine epidemic diarrhea virus (PEDV). Eighteen piglets (Duroc × Landrace × Large, body weight = 2.58 ± 0.05 kg) were divided into three treatment groups based on similar body weights and equal numbers of males and females: the blank control group (CON group), the PEDV infection group (PEDV group), and the NG intervention + PEDV infection group (NG + PEDV group) (n = 6 per group). The experiment lasted for 11 days, comprising a pre-feeding period from days 0 to 3 and a formal experimental period from days 4 to 10. On days 4–10 of the experiment, piglets in the NG + PEDV group were orally administered NG (10 mg/kg). On Day 8 of the experiment, piglets in the PEDV and NG + PEDV groups were inoculated with PEDV (3 mL, 10⁶ 50% tissue culture infective dose (TCID₅₀) per milliliter). On day 11 of the experiment, piglets were euthanized for sample collection. PEDV infection caused significant intestinal damage, including a decreased (p < 0.05) villus height in the duodenum and ileum and an increased (p < 0.05) crypt depth in all intestinal segments. This intestinal damage was accompanied by an impaired absorptive function, as indicated by reduced (p < 0.05) serum D-xylose. Further results showed that PEDV compromised the intestinal antioxidant capacity by decreasing (p < 0.05) glutathione peroxidase and catalase activities, and it stimulated the intestinal inflammatory response by upregulating (p < 0.05) the expression of key inflammatory genes, including regenerating family member 3 gamma (REG3G; duodenum, jejunum, colon), S100 calcium binding protein A9 (S100A9; ileum, colon), interleukin 1 beta (IL-1β; ileum, colon), and S100 calcium binding protein A8 (S100A8; colon). PEDV also suppressed the intestinal lipid metabolism pathway by downregulating (p < 0.05) the ileal expression of Solute Carrier Family 27 Member 4 (SLC27A4), Microsomal Triglyceride Transfer Protein (MTTP), Apolipoprotein A4 (APOA4), Apolipoprotein C3 (APOC3), Diacylglycerol O-Acyltransferase 1 (DGAT1), and Cytochrome P450 Family 2 Subfamily J Member 34 (CYP2J34). Moreover, PEDV suppressed the intestinal antiviral ability by downregulating (p < 0.05) interferon (IFN) signaling pathway genes, including MX dynamin like GTPase 1 (MX1) and ISG15 ubiquitin like modifier (ISG15) in the duodenum; weakened intestinal water and ion transport by downregulating (p < 0.05) aquaporin 10 (AQP10) and potassium inwardly rectifying channel subfamily J member 13 (KCNJ13) in the duodenum, aquaporin 7 (AQP7) and transient receptor potential cation channel subfamily V member 6 (TRPV6) in the ileum, and TRPV6 and transient receptor potential cation channel subfamily M member 6 (TRPM6) in the colon; and inhibited intestinal digestive and absorptive function by downregulating (p < 0.05) phosphoenolpyruvate carboxykinase 1 (PCK1) in the duodenum and sucrase-isomaltase (SI) in the ileum. Notably, NG effectively counteracted these detrimental effects. Moreover, NG activated the IFN signaling pathway in the jejunum and suppressed PEDV replication in the colon. In conclusion, NG alleviates PEDV-induced intestinal injury by enhancing the antioxidant capacity, suppressing inflammation, normalizing the expression of metabolic and transport genes, and improving the antiviral ability. Full article

ADP-ribosylation factor (Arf) proteins are small GTPases that regulate intracellular membrane trafficking and actin remodeling through tightly controlled cycles of GTP binding and hydrolysis. Arf1, a central coordinator of Golgi and endosomal transport, and Arf6, which regulates plasma membranes and endosomal dynamics, have both been implicated in late stages of the HIV-1 life cycle. However, the mechanisms by which these GTPases support viral assembly and release remain incompletely defined. Here, we provide direct evidence that both Arf1 and Arf6 are required for efficient trafficking of the HIV-1 Gag polyprotein, assembly, and virion production. Perturbation of Arf1 function using either GTP-locked (Q71L) or GDP-locked (T31N) mutants significantly reduced virus release, impaired Gag association with membrane compartments, and prevented its accumulation at the plasma membrane. Manipulation of Arf1 cycling through the GTPase-activating protein AGAP1 further demonstrated that dynamic transitions between GTP- and GDP-bound states are essential for productive Gag trafficking. Similarly, expression of a constitutively active Arf6 mutant (Q67L) misrouted Gag to intracellular membranes and markedly suppressed virion release. Importantly, disruption of Arf1 or Arf6 activity did not affect the expression, surface levels, or intracellular distribution of the host restriction factor BST-2. Together, these findings identify Arf1- and Arf6-mediated trafficking pathways as critical host determinants of HIV-1 assembly and release and establish that their functions operate independently of BST-2 antagonism. Full article

Extracellular vesicles (EVs) secreted by Fusarium oxysporum play an important role in the process of its infestation of the host, but the in vitro research system for EVs of F. oxysporum (Fo-EVs) has not yet been improved, and the mechanism of its action remains unclear. In this study, particle size distribution, particle concentration, number of particles per unit of protein, number of particles per unit of mycelial biomass, and concentration of contaminated proteins were used as indicators to evaluate the yield and purity of Fo-EVs. The optimal method for Fo-EV preparation and extraction was screened by comparing liquid culture, solid culture, and solid culture with enzymatic cell wall hydrolysis. The optimal system for Fo-EVs separation and purification was screened by a pairwise combination of three primary methods (Ultracentrifugation (UC), Ultrafiltration (UF), and Polyethylene glycol precipitation method (PEG)) and two secondary methods (Size-exclusion chromatography (SEC) and Aqueous two-phase system (ATPS)), respectively. The protein composition was identified via mass spectrometry technology, followed by GO annotation and GO enrichment analysis using whole-genome proteins as the background. Based on these steps, a Fo-EV protein library was constructed to reveal Fo-EV’s most active biological functions. The results showed that solid culture combined with the UC-SEC method could effectively enrich Fo-EVs with a typical cup-shaped membrane structure. The obtained Fo-EVs had an average particle size of 253.50 nm, a main peak value of 200.60 nm, a particle concentration of 2.04 × 10¹⁰ particles/mL, and a particle number per unit protein of 1.09 × 10⁸ particles/μg, which were significantly superior to those of other combined methods. Through proteomic analysis, 1931 proteins enriched in Fo-EVs were identified, among which 350 contained signal peptides and 375 had transmembrane domains. GO enrichment analysis revealed that these proteins were mainly involved in cell wall synthesis, vesicle transport, and pathogenicity-related metabolic pathways. Additionally, 9 potential fungal EV markers, including Hsp70, Rho GTPase family, and SNARE proteins, were screened. This study constructed an isolation system and a marker database for Fo-EVs, providing a methodological and theoretical basis for in-depth analysis of the biological functions of Fo-EVs. Full article

Mutations in the NF1 gene cause Neurofibromatosis Type 1 (NF1), one of the most common genetic disorders. This gene encodes neurofibromin, a member of the GTPase-activating protein (GAP) family that functions as a negative regulator of RAS signaling. Loss of NF1 function leads to persistent RAS activation and promotes tumor growth. The clinical manifestations of NF1 mainly include pigmentary changes, benign and malignant peripheral nerve sheath tumors, as well as gliomas affecting the central nervous system. Currently, MEK inhibition is the only approved therapy and is primarily effective in controlling plexiform neurofibromas (pNFs). However, more comprehensive treatments are needed to address the full spectrum of NF1 manifestations and malignant transformation. Novel therapeutic strategies, including AAV-based gene therapy aimed at restoring NF1 function, oncolytic herpes simplex virus (oHSV) therapy targeting RAS-dysregulated tumor cells, and chimeric antigen receptor T cell (CAR-T) therapy targeting NF1-associated tumors, are under active investigation. In this review, we explore the genetic mechanisms underlying NF1 and highlight recent advances in therapeutic development with a special focus on AAV-based gene therapies alongside other approaches with recent clinical and translational advancements. Full article

Background/Objectives: Rho small GTPases (RSG), which regulates metastasis, constitute eight subfamilies—“classical” Rho, Rac, cdc42, and “atypical” Rif, Rnd, Wrch, RhoH, and RhoBTB. Their downstream signaling requires switching between GTP-bound active and GDP-bound inactive forms. Classical RSGs, but not atypical RSGs, require regulation by guanine nucleotide exchange factors (GEF), GTPase-activating proteins (GAP) and guanine nucleotide dissociation inhibitors (GDI) to achieve this switch. The objective of this review is to summarize the roles of RSGs in metastatic prostate cancer (mPCa) and their interaction with the androgen receptor (AR), which regulates this disease. Methods: We summarize the literature that describes the role of RSGs in mPCa, and their interaction with the AR. Results: Classical RSGs mostly promote metastasis (except RhoB), whereas atypical RSGs, with exceptions, mostly prevent it. Their role, however, is context-dependent—e.g., RhoB is tumor-suppressive in AR-null PCa but oncogenic in AR-positive tumors. The AR modulates RSG expression transcriptionally, but also affects their function through modulation of GEFs, GAPs, and GDIs. In turn, RSGs also regulate AR transcriptional activity. Interestingly, RSGs and the AR have non-genomic interactions via membrane-localized AR (mAR) not affected by AR inhibitors. Conclusions: Drugs that target RSGs are needed along with AR inhibitors to prevent mPCa progression. Full article

Background/Objective: Larazotide acetate (LA) is a synthetic octapeptide under development as a therapeutic candidate for celiac disease, acting to reduce intestinal permeability and regulate tight junctions (TJs). Although several studies have shown barrier-protective effects, the cellular mechanisms underlying LA’s actions in the intestinal epithelium remain unclear. This study aimed to elucidate the mechanistic roles of LA in maintaining intestinal epithelial integrity during cellular injury. Methods: C2BBe1 and leaky IPEC-J2 cell monolayers were pretreated with 10 mM LA and subjected to anoxia/reoxygenation (A/R) injury. Transepithelial electrical resistance (TEER), TJ protein localization, and phosphorylation of myosin light chain-2 (MLC-2) were analyzed. In addition, RNA sequencing was conducted to identify differentially expressed genes and signaling pathways affected by LA treatment. Results: LA pretreatment significantly increased TEER and preserved TJ protein organization during A/R injury. Transcriptomic analysis revealed enrichment of genes related to barrier regulation, small GTPase signaling, protein phosphorylation, proliferation, and migration. LA pretreatment markedly reduced MLC-2 phosphorylation, likely through modulation of the ROCK pathway, consistent with RNA-seq findings. Moreover, LA enhanced cellular proliferation, validating transcriptomic predictions. Conclusions: LA exerts a protective effect on intestinal epithelial integrity by stabilizing tight junctions, reducing MLC-2 phosphorylation, and promoting epithelial proliferation. These findings highlight a novel mechanism for LA and support its therapeutic potential in treating gastrointestinal disorders associated with “leaky gut” and mucosal injury. Full article

The proliferation and migration of pulmonary artery smooth muscle cells (PASMCs) are key pathological features of vascular remodeling during pulmonary hypertension. Platelet-derived growth factor (PDGF) signaling is a major contributor to these processes. Given the importance of microRNA (miRNA) regulation in the PDGF signaling pathway in PASMCs, we hypothesized that imatinib, a tyrosine kinase inhibitor, modulates the expression levels of miRNAs responsive to PDGF signaling to ameliorate the PDGF signaling-induced PASMC phenotype. In this study, we investigated the role of miR-335-5p in PDGF signaling-induced PASMC proliferation and migration, as well as the involvement of imatinib in the regulatory network of miR-335-5p. miR-335-5p was identified as a critical negative regulator of PDGF signaling. Functional assays revealed that miR-335-5p significantly inhibits PASMC proliferation and migration. Through target prediction and validation, Rho GTPase Activating Protein 18 (ARHGAP18) was identified as a novel direct target of miR-335-5p. In addition, ARHGAP18 was found to play an essential role in regulating PASMC proliferation and migration. Although miR-335-5p was downregulated upon PDGF-BB stimulation, its expression was restored by imatinib. These findings highlight the important role of the imatinib–miR-335-5p–ARHGAP18 axis as a potential therapeutic target for pathological vascular remodeling. Full article

Background/Objectives: Mass-forming chronic pancreatitis (MFP) and pancreatic ductal adenocarcinoma (PDAC) can present with overlapping radiological, clinical, and serological features in patients with underlying chronic pancreatitis (CP), making differential diagnosis particularly challenging. Current diagnostic tools, including CA19-9 and endoscopic ultrasound (EUS) imaging, often lack the specificity needed to reliably distinguish between these conditions. The objective of this study was to investigate whether the proteomic profiling of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) samples could provide molecular-level discrimination between MFP and PDAC in patients with CP. Methods: Thirty CP patients with solid pancreatic lesions were prospectively enrolled: 15 with histologically confirmed PDAC and 15 with MFP. Traditional diagnostic parameters, including CA19-9 levels and EUS characteristics, were recorded but found insufficient for differentiation. EUS-FNA samples were analyzed using label-free mass spectrometry. A total of 928 proteins were identified in PDAC samples and 555 in MFP samples. Differential abundance analysis and pathway enrichment were performed. Results: Overall, 88 proteins showed significant differential abundance between PDAC and MFP samples, of which 26 met stringent statistical thresholds. Among these, Carboxylesterase 2 (CES2), Carcinoembryonic Antigen-Related Cell Adhesion Molecule 1 (CEACAM1), Lumican (LUM), Transmembrane Protein 205 (TMEM205), and NAD(P)H Quinone Dehydrogenase 1 (NQO1) emerged as key discriminatory proteins. Pathway enrichment analysis revealed distinct biological processes between the groups, including mitochondrial fatty acid β-oxidation, Rho GTPase signaling, and platelet degranulation. Conclusions: Proteomic signatures derived from EUS-FNA samples offer a promising molecular approach to distinguish inflammatory pseudotumoral lesions from malignant pancreatic tumors in CP patients. This minimally invasive strategy could enhance diagnostic accuracy where current methods fall short. Further validation in larger, multicenter cohorts is warranted to confirm these findings and evaluate their clinical applicability. Full article

It has previously been reported that the RhoA/Rho-associated kinase (ROCK) pathway is involved in depolarization-induced contraction triggered by high [K⁺] stimulation in rat caudal arterial smooth muscle. Furthermore, we reported that activation of the upstream Ca²⁺-dependent proline-rich tyrosine kinase 2 (Pyk2) leads to phosphorylation of myosin targeting subunit of myosin light chain phosphatase (MYPT1) and 20 kDa myosin light chain (LC₂₀). These findings suggest that Rho guanine nucleotide exchange factors (RhoGEFs) or Rho GTPase-activating proteins (RhoGAPs) may mediate RhoA activation downstream of Pyk2, thereby contributing to depolarization-induced contraction. However, it remains unclear whether Pyk2 directly interacts with RhoGEFs or RhoGAPs. In this study, we investigated the interaction between Pyk2 and RhoGEFs or RhoGAPs during depolarization stimulation of rat caudal arterial smooth muscle. We examined the interaction between Pyk2 and RhoGEFs or RhoGAPs, which previously were identified in smooth muscle, specifically in rat caudal arterial smooth muscle, in response to 60 mM K⁺ stimulation by immunoprecipitation analysis. ArhGEF11, ArhGEF12, phosphorylated ArhGAP42 at Tyr792 (pTyr792-ArhGAP42) and phosphorylated ArhGAP42 at Tyr376 (pTyr376-ArhGAP42) co-immunoprecipitated with Pyk2. The co-immunoprecipitation of pTyr792-ArhGAP42, but not pTyr376-ArhGAP42, with Pyk2 was inhibited by a Pyk2 inhibitor, sodium salicylate. Furthermore, 60 mM K⁺ stimulation increased ArhGAP42 phosphorylation at Tyr792, which was also suppressed by sodium salicylate. These findings indicate that Pyk2-mediated phosphorylation of ArhGAP42 at Tyr792 may play a role in depolarization-induced contraction of rat caudal arterial smooth muscle. Full article

The function of pleckstrin homology (PH) domains is to recognize and bind to specific phosphoinositides in the membranes as part of diverse cellular signaling processes. The structure of some PH domains has been solved by X-ray crystallography, but structures of many PH domains remain to be elucidated. In green alga Chlamydomonas reinhardtii, none of the PH domains have been crystallized or characterized. The goal of our study was to model and characterize in detail the structures of all eleven of the PH domains identified in C. reinhardtii. Our computational strategy of integrating the information available on sequence, structure, and function with modeling and biophysical characterization has uncovered new biological predictions for these proteins. These predictions can be validated by future rationally designed experimental studies as an extension of this work. Our results suggest that nine of the eleven C. reinhardtii PH domains show the classical electrostatic polarization of PH domains with a positively charged binding pocket and negatively charged opposing end. Our docking results predict only two PH domains bind specifically to a particular phosphoinositide, while all the other nine PH domains may be able to bind various inositol phospholipids. The lack of preference for a specific phosphoinositide headgroup implies that the positive charge in the binding pocket of the PH domains may be crucial in driving the interaction with the negatively charged phosphoinositides in a non-specific or promiscuous manner. We identified putative homologs of Dynamin GTPase, calcium/calmodulin-dependent kinase, Arf GAP, Rhythm of Chloroplast 23 (ROC23), and oxysterol binding proteins in C. reinhardtii that contain PH domains. In addition, we identified two PH domain-containing proteins that may play a role in the mating process and others that may be important for signaling under phosphate deficiency. Full article

Oxaliplatin-induced peripheral neurotoxicity (OIPN) represents a major challenge in cancer therapy, characterized by dorsal root ganglia (DRG) inflammation and disruption of neuro-glio-vascular unit function. In this study, we investigated the involvement of the scaffold protein IQ Motif Containing GTPase Activating Protein 1 (IQGAP1) and dehydropeptidase-1 (DPEP1) in the DRG response to oxaliplatin (OxPt) and the modulatory effect of cilastatin. Behavioral assessment showed a robust nocifensive response to cold stimuli in OxPt-treated rats, attenuated by cilastatin co-treatment. Our confocal study revealed different cellular and subcellular expression patterns of IQGAP1 and DPEP1 in neurons, glia, and endothelial cells, where both signals overlap approximately one-third. OxPt enhanced cytosolic aggregation of IQGAP1 in neurons and upregulation of signal in glia, accompanied by co-expression of TNFα and IL-6, indicating involvement in the inflammatory process. DPEP1 showed altered subcellular distribution in OxPt-treated animals, suggesting a potential role in the inflammatory cascade. Notably, IQGAP1 expression was diminished in endothelial membranes under OxPt, while cilastatin preserved endothelial IQGAP1-CD31 colocalization, suggesting partial restoration of blood-nerve barrier integrity. These findings identify IQGAP1 and DPEP1 as key players in DRG inflammation and position cilastatin as a promising modulator of OIPN through neuro-glio-vascular stabilization. Full article