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At least 19 recordsLinked to original sources

Revealing novel protein interaction partners of glyphosate in Escherichia coli.

Despite all debates about its safe use, glyphosate remains the most widely applied active ingredient in herbicide products, with renewed approval in the European Union until 2033. Non-target organisms are commonly exposed to glyphosate as a matter of its mode of application, with its broader environmental and biological impacts remaining under investigation. Glyphosate displays structural similarity to phosphoenolpyruvate (PEP), thereby competitively inhibiting the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), crucial for the synthesis of aromatic amino acids in plants, fungi, bacteria, and archaea. Most microbes, including the gut bacterium Escherichia coli (E. coli), possess a glyphosate-sensitive class I EPSPS, making them vulnerable to glyphosate's effects. Yet, little is known about glyphosate's interactions with other bacterial proteins or its broader modes of action at the proteome level. Here, we employed a quantitative proteomics and thermal proteome profiling (TPP) approach to identify novel protein binding partners of glyphosate in the E. coli proteome. Glyphosate exposure significantly altered amino acid synthesizing pathways. The abundance of shikimate pathway proteins was increased, suggesting a compensatory mechanism. Extracellular riboflavin concentrations were elevated upon glyphosate exposure, while intracellular levels remained stable. Beyond the target enzyme EPSPS, thermal proteome profiling indicated an effect of glyphosate on the thermal stability of certain proteins, including AroH and ProA, indicating interactions. Similar to the competitive binding between PEP and glyphosate at EPSPS, one reason for the interaction of AroH and ProA with the herbicide could be a high structural similarity between their substrates and glyphosate. Overall, glyphosate induced metabolic disturbances in E. coli, extending beyond its primary target, thereby providing new insights into glyphosate's broader impact on microbial systems.

Glyphosate

Rasputin/G3BP mediates subversion of antiviral immunity by o'nyong-nyong virus in Anopheles coluzzii.

Cellular G3BP proteins are essential for alphavirus infection in both vertebrate and mosquito hosts, but the underlying mechanism of their proviral activity is poorly understood in any host. Whether the mosquito G3BP ortholog, Rasputin (Rin), interacts with host immunity to influence alphavirus infection has not been investigated, and anopheline mosquito interactions with arboviruses have been little studied. Here, we find that Rin silencing in Anopheles mosquitoes results in decreased ONNV infection levels, indicating a proviral activity for Anopheles Rin. We find that Rin function is required to maintain basal activity of the antiviral Imd and JAK/STAT pathways in uninfected mosquitoes. However, during ONNV infection, the control of the Imd pathway by Rin activity appears corrupted because Rin silencing leads to overexpression of the Imd positive regulator, Rel2. Thus, silencing of Rin both augments Rel2 transcript abundance and decreases ONNV load. Co-silencing of Rel2 with Rin restores normal ONNV infection levels, indicating that Rin activity is required to inhibit Imd function during ONNV infection, and which explains most of the Rin proviral phenotype. In addition, we show that the ONNV non-structural protein 3 (nsP3), which binds to Rin, strongly alters the pattern of Anopheles cellular protein partners interacting with Rin. In the presence of ONNV nsP3, 48 Rin-binding host proteins are unchanged but seven binding proteins are excluded and eight new cellular proteins bind Rin. The altered cellular protein partners are candidate host factors involved in viral subversion of Rin control over Imd activity. Overall, these results reveal a molecular mechanism in which ONNV, probably through nsP3, co-opts the normal Rin function for basal cellular immune activity by subverting the Imd antiviral pathway to promote infection. These results may be generalizable for Rin function during alphavirus infection of other mosquitoes, as well as for G3BP function in the mammalian host, and could offer a target for development of vector-based genetic control tools against arbovirus transmission.

Animals

The msf gene causes condition-specific shifts in global gene expression in Haemophilus influenzae.

UNLABELLED: Haemophilus influenzae is a diverse human-restricted bacterium that normally colonizes the healthy nasopharynx but also causes common infections. Comparisons of clinical isolate genomes previously identified a gene, msf, that contained Sel1-like repeats that were associated with clinical disease. Mutant analysis had further found that msf improved survival in macrophages and increased systemic infection in an animal model. However, the role of msf in other conditions and its molecular function remain unknown. To identify protein-protein interactions with Msf, a yeast two-hybrid screen against an H. influenzae prey library was conducted, which found potential interactions with lipoprotein exporter protein LolD and an autotransporter adhesin Hap. To identify effects of msf on gene expression, we compared wild-type and mutant strains grown in multiple culture conditions by RNA-seq. The results indicate that msf modulates global gene expression in a condition-dependent manner, exerting an especially strong influence in starved surface-attached biofilm cells. The few consistent changes in mutants' planktonic exponential and stationary phases included decreased expression of two paralogous autotransporter adhesins. By contrast, mutant cells in starved surface-attached biofilms had dramatic changes in expression, including upregulation of protein translation and downregulation of alternative carbon metabolism. However, assays of 24 hour biofilm phenotypes found only subtle gene expression changes. Together, the results point to a speculative model of Msf functioning as an envelope-associated chaperone whose presence affects the relative expression of proteins at the outer membrane. IMPORTANCE: Comparing genomes from different clinical isolates of the same pathogenic bacterial species has identified genes associated with virulence, but many of these are understudied or have no known function. The msf gene was previously implicated as a virulence factor in Haemophilus influenzae, a common cause of mucosal diseases including middle-ear and chronic lung infections. This study finds that the msf gene causes condition-specific changes in gene expression, with especially dramatic changes in starved surface-attached biofilm cells. Along with identification of putative protein-protein interaction partners, the results provide new clues as to the molecular and cellular function of Msf, potentially as an envelope-associated chaperone involved in membrane protein trafficking. Understanding how virulence-associated genes like msf modulate bacterial responses to the environment may help explain why some bacterial strains remain harmless colonizers while others become pathogens.

Haemophilus influenzae

Identification of interaction partners of outer inflammatory protein A: Computational and experimental insights into how Helicobacter pylori infects host cells.

Outer membrane proteins (OMPs) play a key role in facilitating the survival of Helicobacter pylori within the gastric tissue by mediating adherence. Among these proteins, Outer inflammatory protein A (OipA) is a critical factor in H. pylori colonization of the host gastric epithelial cell surface. While the role of OipA in H. pylori attachment and its association with clinical outcomes have been established, the structural mechanisms underlying OipA's action in adherence to gastric epithelial cells remain limited. Our study employed experimental and computational approaches to investigate the interaction partners of OipA on the gastric epithelial cell surface. Initially, we conducted a proteomic analysis using a pull-down assay with recombinant OipA and gastric epithelial cell membrane proteins to identify the OipA interactome. This analysis revealed 704 unique proteins that interacted with OipA. We subsequently analyzed 16 of these OipA partners using molecular modeling tools. Among these 16 partners, we highlight three human proteins, namely Hepatocyte growth factor (HGF), Mesenchymal epithelial transition factor receptor (Met), and Adhesion G Protein-Coupled Receptor B1 (AGRB1) that could play a role in H. pylori adherence to the gastric epithelial cell surface with OipA. Collectively, these findings reveal novel host interactions mediated by OipA, suggesting their potential as therapeutic targets for combating H. pylori infection.

Helicobacter pylori

STUPPIT is a proximity labeling tool for labeling intermediary proteins that bridge two non-interacting proteins.

Decoding the complexities of signaling pathways is fundamental for deciphering the mechanisms underlying tissue development, homeostasis, and disease pathogenesis. Proximity labeling tools have been instrumental in identifying upstream or downstream effectors of specific proteins within signaling pathways. However, currently, there are no tools available to directly label and capture intermediary proteins that bridge two non-interacting proteins. Here, we developed Split-TurboID and PUP-IT based Protein Identification Tool (STUPPIT), a novel method combining split-TurboID and PUP-IT to biotinylate intermediary proteins of two non-interacting proteins through a two-step enzymatic reaction. STUPPIT was validated using three well-characterized protein triads, including YAP1/AMOT/β-actin, YAP1/LATS1/MOB1A, and β-catenin/α-catenin/β-actin using HEK293T human cell lines. Combining STUPPIT and proteomics, we identified novel intermediary proteins including ERC1 and USP7, which interacted both with β-catenin and SMAD4, key components of the Wnt and BMP signaling pathways. In conclusion, STUPPIT represents a powerful tool for labeling and capturing intermediary proteins between non-interacting partners, offering new insights into protein-protein interactions and advancing signal transduction research.

Humans

Knockdown Proteomics Reveals USP7 as a Regulator of Cell-Cell Adhesion in Colorectal Cancer via AJUBA.

Ubiquitin-specific protease 7 (USP7) is implicated in many cancers including colorectal cancer in which it regulates cellular pathways such as Wnt signaling and the P53-MDM2 pathway. With the discovery of small-molecule inhibitors, USP7 has also become a promising target for cancer therapy and therefore systematically identifying USP7 deubiquitinase interaction partners and substrates has become an important goal. In this study, we selected a colorectal cancer cell model that is highly dependent on USP7 and in which USP7 knockdown significantly inhibited colorectal cancer cell viability, colony formation, and cell-cell adhesion. We then used inducible knockdown of USP7 followed by LC-MS/MS to quantify USP7-dependent proteins. We identified the Ajuba LIM domain protein as an interacting partner of USP7 through co-IP, its substantially reduced protein levels in response to USP7 knockdown, and its sensitivity to the specific USP7 inhibitor FT671. The Ajuba protein has been shown to have oncogenic functions in colorectal and other tumors, including regulation of cell-cell adhesion. We show that both knockdown of USP7 or Ajuba results in a substantial reduction of cell-cell adhesion, with concomitant effects on other proteins associated with adherens junctions. Our findings underlie the role of USP7 in colorectal cancer through its protein interaction networks and show that the Ajuba protein is a component of USP7 protein networks present in colorectal cancer.

Ubiquitin-Specific Peptidase 7

Genome-wide identification of the carotenoid cleavage dioxygenase gene family in wheat and analysis of the TaDREB-7A-TaNCED9a regulatory module conferring drought tolerance.

Carotenoid cleavage dioxygenases (CCDs) play critical roles in plant growth, development, and abiotic stress responses, yet their genome-wide identification and drought response mechanisms remain unexplored in wheat. In this study, 34 TaCCD genes were identified in wheat, distributed across 15 chromosomes and phylogenetically classified into five subfamilies. Gene structure analysis indicated that members within each subfamily shared conserved motifs and similar intron-exon arrangements. Cis-regulatory element analysis suggested the potential roles of these genes in stress adaptation, developmental processes, and hormone signaling. Moreover, prediction of tertiary structures and protein-protein interactions revealed unique structural features and potential interacting partners of the TaCCD proteins. In addition, TaNCED9a, a member of the TaCCD family, showed the highest transcript level in wheat roots among all detected TaCCD genes and was significantly induced by drought stress. Subcellular localization assay indicated that TaNCED9a was located in chloroplasts. Downregulation of TaNCED9a expression led to reduced drought resistance in wheat, accompanied by an accumulation of reactive oxygen species and a decrease in endogenous abscisic acid levels. Using yeast one-hybrid, dual-luciferase, and tobacco transient co-expression assays, the upstream regulatory factor TaDREB-7A was identified, which can regulate the expression of TaNCED9a. Additionally, a KASP molecular marker was developed to identify the superior haplotype TaNCED9a-HapI, which exhibited a significantly higher germination rate compared to TaNCED9a-HapII under drought conditions, and was predominant in wheat. These results offer valuable insights into the TaCCD gene family's response mechanisms to drought stress in wheat, simultaneously identifying promising genetic resources for enhancing drought tolerance through molecular breeding.

CCD

Regulation of TET function by PROSER1 in development and hematologic malignancies.

Ten eleven translocation (TET) proteins are central regulators of DNA methylation homeostasis and play essential roles in development and disease, including hematopoietic malignancies. Among the three TET family members, mutations in TET2 are frequently observed in hematologic disorders. TET enzymes catalyze the iterative oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) and further oxidized derivatives, enabling DNA demethylation. Beyond catalysis, TET proteins also perform important non-enzymatic functions mediated through interactions with diverse protein partners, highlighting the importance of defining their regulatory interactome. Previous studies identified several TET-associated factors, including O-Linked N-acetylglucosamine transferase (OGT), members of the Drosophila behavior/human splicing (DBHS) protein family, and proline and serine-rich protein 1 (PROSER1). However, these interactions were largely considered independently. Recent findings now demonstrate that TET proteins, OGT, PROSER1, and DBHS proteins assemble into a higher-order regulatory unit termed the TOPD (TET-OGT-PROSER1-DBHS) complex. In this review, we discuss how TOPD provides a conceptual framework for understanding multicomponent regulation of TET function, spatial control of DNA demethylation, and maintenance of epigenetic homeostasis, with implications for developmental syndromes and hematopoiesis.

Humans

Novel CDK-independent function of CDC25 phosphatases in mRNA translation.

Molecular and functional networks driving coordination between cell cycle and mRNA translation remain to be explored. Here, we use mass spectrometry-based proteomics to comprehensively investigate the interactome and phosphoproteome of the cell cycle regulator CDC25A. We identify actors of mRNA regulation, such as RNA-binding proteins and translation factors, as interacting partners of CDC25A. CDC25A overexpression increases global translation, whereas catalytic inactivation or pharmacological inhibition decreases protein synthesis. A Cyclin-Dependent Kinase (CDK) interaction-deficient mutant of CDC25A also enhances translation, indicating a CDK-independent role. Our results further reveal an interplay between CDC25A and CDC25B whereby downregulation of CDC25A leads to compensatory overexpression of CDC25B. The roles of CDC25A and CDC25B in mRNA translation are independent of their roles in the cell cycle, with CDC25A possibly regulating translation elongation and CDC25B rather involved in initiation. In acute myeloid leukemia cells, CDC25A depletion also inhibits translation, suggesting its potential relevance as a therapeutic target. We propose that CDC25 phosphatases might be signaling platforms coordinating cell cycle progression with protein synthesis.

cdc25 Phosphatases

Arginine methylation-dependent METTL14-SMN interaction regulates RNA m6A homeostasis.

N6-methyladenosine (m6A) homeostasis is essential for development, and its dysregulation is linked to cancers and neurological disorders. However, the mechanisms regulating m6A remain unclear. Here, we identify the survival of motoneuron (SMN) protein as a novel interaction partner of METTL14, a key component of the m6A methyltransferase complex. SMN binds METTL14 via its Tudor domain in an arginine methylation-dependent manner. Mutations in the SMN Tudor domain identified in spinal muscular atrophy (SMA) disrupt its interaction with METTL14 and reduce m6A levels in patient-derived fibroblasts, linking m6A dysregulation to SMA pathology. Both SMN knockdown and SMA mutations impair m6A deposition on the mRNAs of DNA repair genes, mirroring the effects of METTL14 hypomethylation. Consequently, SMA patient fibroblasts are hypersensitive to DNA-damaging agents due to reduced levels of DNA repair gene expression. To explore the function of METTL14 arginine methylation in vivo, we generated a Mettl14 methylation-deficient mouse model (Mettl14RK). Although this model does not show SMA-like phenotypes, the mutants are partially embryonic lethal and show abnormal hematopoiesis, underscoring a role for methylated METTL14 in early development.

Methyltransferases

Loss of the Mechanistic Target of Rapamycin Complex 1 Causes a Lethal Alpha-1 Antitrypsin Deficiency-Associated Liver Disease.

BACKGROUND & AIMS: SERPINA1 mutations cause retention of the otherwise secreted alpha-1 antitrypsin and lead to the proteotoxic alpha-1 antitrypsin deficiency-related liver disease. As mechanistic target of rapamycin is a key coordinator of proteostasis, we studied its role in alpha-1 antitrypsin deficiency-related liver disease. METHODS: PiZ mice overexpressing the characteristic SERPINA1 mutation were mated with rodents harboring a hepatocyte specific-ablation of the interaction partners regulatory-associated protein of mechanistic target of rapamycin or rapamycin-insensitive companion of mammalian target of rapamycin, corresponding to mechanistic target of rapamycin complexes 1 or 2, or with mice lacking mechanistic target of rapamycin. Serum proteomics, liver bulk proteomics, spatial proteomics, and metabolomics were applied to characterize molecular and metabolic alterations. RESULTS: At 2 months of age, PiZ-mTORΔhep and PiZ-RaptorΔhep but not PiZ-RictorΔhep mice showed signs of increased liver injury and mortality despite diminished hepatic alpha-1 antitrypsin accumulation. PiZ-RaptorΔhep animals displayed increased levels of the proapoptotic protein C/EBP homologous protein, but C/EBP homologous protein ablation did not rescue the phenotype. Serum proteomics revealed no signs of advanced synthetic liver failure but immature hepatocellular products. Liver bulk proteomics and small metabolite measurement demonstrated a metabolic reprogramming of PiZ-RaptorΔhep mice. Spatial proteomics revealed alterations in liver zonation with increased ammonia levels as the likely cause of death in PiZ-RaptorΔhep animals. CONCLUSIONS: In summary, in alpha-1 antitrypsin deficiency-related proteotoxic liver injury, regulatory-associated protein of mechanistic target of rapamycin preserves a liver zonation, thereby protecting from lethal metabolic dysregulation.

Animals

A novel reverse lipase toxin substrate of the Staphylococcus aureus type VII secretion system.

The type VII secretion system (T7SS) is found in many Gram-positive bacteria and secretes toxins with antibacterial activity. Most characterized substrates have an N-terminal LXG domain that interacts with other helical partner proteins to form a composite T7SS targeting signal. Here we describe only the second substrate family to have a reverse domain arrangement. We show that TslM has a C-terminal LXG-like domain and an N-terminal lipase domain that has phospholipase activity. Secretion of TslM requires a single helical partner protein that binds to the TslM C-terminus, and its toxic activity is neutralized by a distinct family of membrane proteins. Genome analysis reveals that Staphylococcus aureus strains have the capacity to encode up to seven paralogous copies of this toxin family. Taken together our findings show that lipases are an important component of the staphylococcal T7SS toxin arsenal, and that toxins with a reverse domain arrangement are more widespread than previously appreciated.

Staphylococcus aureus

Library-based, multiplexed strategy for mapping protein interaction networks via crosslinking.

BACKGROUND: Protein-protein interactions are fundamental to cellular function, yet resolving their interaction interfaces and dynamic behaviors in native biological contexts remains challenging, particularly for weak or transient interactions. Crosslinking strategies based on noncanonical amino acids offer an effective means to capture such interactions; however, traditional single-site incorporation provides limited coverage and may overlook critical interaction hotspots. RESULTS: By employing a mutagenesis library, multiple interaction partners and cross-linking sites of a target protein can be simultaneously screened in a single experiment, without prior knowledge of its precise structural or functional features, enabling effective and unbiased analysis of its interaction network. In this study, we constructed an amber codon-scanning mutagenesis library of PSMD10, facilitating independent incorporation of the photocrosslinking ncAA p-azido-phenylalanine at multiple distinct residues. This approach allowed us to systematically interrogate and precisely map potential interaction regions across the protein surface. Coupled with crosslinking mass spectrometry, we identified multiple residues involved in intermolecular interactions, as well as previously unreported interaction partners, including T2FA, TBA1C, and ATRIP. CONCLUSIONS: These findings expand our understanding of PSMD10-associated proteasome interactome, demonstrate a multiplexed strategy for in situ mapping of protein interaction interfaces with broad coverage, and offer a valuable platform for developing therapeutics that target protein-protein interactions.

Protein Interaction Mapping

Dual proximity-based interactome mapping of FKBP51 and FKBP52 uncovers shared metabolic networks.

The 51 kDa FK506-binding protein (FKBP51) has been studied for its involvement in regulating multiple biological systems, particularly as a regulator of steroid hormone receptors, but roles in metabolism, pain response, cell survival, protein turnover, autophagy, immune response, and insulin signaling have also been described. Genetic variants of FKBP51 are associated with various stress-related mental disorders. While recent research has clarified aspects of these processes, the complete range of FKBP51 interactions remains undetermined. FKBP52, a closely related homolog, also affects similar pathways. Recent studies have identified new protein partners for FKBP51 and FKBP52, suggesting an even broader interactome with transient associations. To further characterize interactions, TurboID-based proximity labeling was performed in HeLa cells. Proteomic analysis confirmed known FKBP51 and FKBP52 interactions, while also identifying additional shared and unique binding partners with strong enrichment in metabolic pathways, amino acid biosynthesis, and carbon metabolism. Although FKBP51 and FKBP52 proximal proteins were primarily cytosolic, FKBP51 showed additional associations with exosomal proteins while FKBP52 engaged with additional nuclear proteins. These findings highlight the overlapping roles in metabolic signaling and differentiate pathway-specific partners.

Tacrolimus Binding Proteins

Identification of Plant Chromatin Interaction Networks Using IP-MS and co-IP.

Proteins often act in concert to perform their function. Thus, the identification of protein complexes is crucial if we want to understand how they work. In this chapter, we present a highly sensitive protocol for the immunoprecipitation of nuclear chromatin-linked proteins in Arabidopsis thaliana that does not rely on time-consuming nuclei extraction. Interaction partners are identified using mass spectrometry and confirmed by co-immunoprecipitation. To help solubilize chromatin-bound proteins and eliminate nonspecific interactions of proteins binding the same DNA stretch, we include an enzymatic digestion step to remove DNA before immunoprecipitation. Our protocol offers a simplified process using optimized buffers, which facilitates quick and effective immunoprecipitation. The outcome is high-quality eluates that are ideal for identifying proteins through MS.

Chromatin

Spatio-genetically coordinated TPR domain-containing proteins modulate c-di-GMP signaling in Vibrio vulnificus.

Vibrio species, which include several pathogens, are autochthonous to estuarine and warm coastal marine environments, where biofilm formation bolsters their ecological persistence and transmission. Here, we identify a bicistronic operon, rcbAB, whose products synergistically inhibit motility and promote biofilm maturation post-attachment by modulating intracellular c-di-GMP levels in the human and animal pathogen V. vulnificus. RcbA contains an N-terminal tetratricopeptide repeat (TPR) domain and a structured C-terminal region of unknown function, while RcbB possesses an N-terminal TPR domain and a C-terminal GGDEF domain characteristic of diguanylate cyclases. The TPR domain of RcbB represses its diguanylate cyclase activity, while RcbA's TPR domain and C-terminal region co-operatively de-repress it. Localization of both proteins to the flagellar pole is TPR-dependent but not co-dependent, although RcbA anchors RcbB to the pole in the absence of polar landmarks such as HubP and flagella. The conservation of rcbAB across diverse bacterial taxa substantiates its fundamental importance in bacterial biology. This work demonstrates how spatio-genetically coordinated TPR domain-containing proteins modulate c-di-GMP signaling, contributing to our understanding of biofilm formation in Vibrio species and potentially other bacteria. It also reveals the first evidence of inter-protein interaction via the TPR domains of both partners, challenging the conventional paradigm in which only one bears the domain.

Vibrio vulnificus

Mechanisms of enhanced or impaired DNA target selectivity driven by protein dimerization.

Successful DNA transcription demands coordination between proteins that bind DNA while simultaneously binding to one another to form dimers or higher-order complexes. For proteins with numerous DNA targets throughout the genome, measurements that report on their dwell time or occupancy thus represent a convolution over a population interacting with specific DNA, nonspecific DNA, or protein partners on DNA. Dimerization is known to add contacts that can help a single protein to stably bind DNA. However, we show here that dimerization can also impair measured dwell times and occupancy on target sequences because the population redistributes across DNA. We combine mass-action kinetic models of pairwise reversible reactions between proteins and DNA with theory and spatial stochastic simulations to isolate the role of dimerization on observed DNA dwell times, occupancy, and spatial distribution of proteins on DNA. Three key themes emerge: (i) Protein-protein interactions, in addition to protein-DNA interactions, can localize a protein to DNA, and relative binding rates can thus widely tune dwell times. (ii) Dimensional reduction achieved through nonspecific binding and subsequent 1D diffusion controls the order-of-magnitude of enhancements despite nucleosome barriers. (iii) Dimerization enhances selectivity for locally clustered targets and often impairs binding to widely-spaced targets by sequestration. Compared with ChIP-seq data, our model explains how the distribution of the essential GAF protein throughout the genome is highly selective for clustered targets due to protein interactions. This model framework predicts when even weak dimerization can redistribute and stabilize proteins on DNA as a necessary part of transcription.

DNA binding

Integrated molecular and immune profiling identifies FOXA1 as a complementary co-target to MUC1 for bispecific immunotherapy in breast cancer.

In breast cancer immunotherapy, Mucin 1 (MUC1) is a well-established target with promising preclinical results; however, single targeting of MUC1 has demonstrated limited efficacy in clinical trials, largely due to tumor heterogeneity, diverse glycosylation patterns, and an immunosuppressive TME. Identification of complementary co-targets enables bi-specific or dual-target immunotherapy, limiting antigen escape, improving specificity, and reducing relapse. Here, we employed a comprehensive multi-layered analytical approach to evaluate MUC1 expression, clinical relevance, and methylation status, followed by systematic screening of MUC1-correlated genes. Antigenicity prediction and protein-protein interaction analyses identified Forkhead Box A1 (FOXA1) as a potential functional partner. Expression analysis revealed concordant patterns of MUC1 and FOXA1 across breast cancer samples, while network mapping demonstrated shared interactions with adhesion-associated proteins, including CTNNB1, CTNND1, and CDH1, suggesting roles in epithelial organization and tumor progression. Further validation using gene expression datasets from Indian breast cancer cohorts confirmed consistent expression and correlation patterns, supporting reproducibility across populations. Immune profiling revealed an inverse association between MUC1-FOXA1 co-expression and immune-related gene signatures, with high co-expression linked to reduced infiltration of dendritic cells, CD4⁺ and CD8⁺ T cells, macrophages, and natural killer cells, indicative of an immunosuppressive microenvironment. Negative correlations with MHC Class I genes further suggested impaired antigen presentation. Epitope prediction identified high-affinity peptides from both targets with strong MHC Class I binding potential. Collectively, these findings support the associated role of MUC1 and FOXA1 as dual immunotherapeutic targets in breast cancer.

Hepatocyte Nuclear Factor 3-alpha