RPS27A Human

What is the basic structure and function of RPS27A in human cells?

RPS27A is a fusion protein consisting of ubiquitin at the N-terminus and ribosomal protein S27a at the C-terminus. When expressed, the protein undergoes post-translational processing that generates free ubiquitin monomer and ribosomal protein S27a . RPS27A is a component of the 40S subunit of the ribosome and belongs to the S27AE family of ribosomal proteins . It contains C4-type zinc finger domains and is predominantly located in the cytoplasm .

The protein serves dual critical functions:

• As part of the 40S ribosomal subunit, it participates in protein synthesis

• Through its ubiquitin component, it contributes to the targeting of cellular proteins for degradation by the 26S proteasome

This unique structure positions RPS27A at the intersection of protein synthesis and degradation pathways, allowing it to influence multiple cellular processes.

What experimental methods are most effective for detecting RPS27A expression in human tissues?

For comprehensive RPS27A detection and analysis, researchers should consider the following methodological approaches:

• Immunohistochemistry (IHC): Effective for visualizing RPS27A protein expression in tissue sections, as demonstrated in studies of human and mouse liver samples

• Public database analysis: Multiple platforms can be utilized for in silico analysis:

  • UALCAN: For cancer expression profiling

  • HPA (Human Protein Atlas): For protein expression patterns

  • TISIDB, TIMER: For immune infiltration correlation

  • cBioPortal: For genomic alterations

  • cancerSEA: For functional analyses

• Coculturing assays: Particularly valuable for studying RPS27A's effects on immune cell interactions, such as macrophage polarization

• Recombinant protein approaches: Using control fragments (such as Human RPS27A aa 94-155) for validation experiments in immunohistochemistry, immunocytochemistry, and Western blotting

When designing experiments, researchers should note that RPS27A shows high sequence identity across species (98% with mouse and rat orthologs), which can facilitate translational research between model organisms and humans .

How is RPS27A dysregulation associated with cancer progression?

RPS27A shows significant dysregulation across multiple cancer types with important implications for cancer biology:

Research indicates that RPS27A expression levels correlate with clinicopathologic features and prognosis in human cancers . The protein participates in the regulation of genomic alterations and heterogeneity, showing associations with tumor mutation burden, microsatellite instability, and neoantigen formation .

Mechanistically, RPS27A overexpression in HCC cells has been experimentally demonstrated to enhance cellular proliferation, migration, and invasion capabilities, suggesting direct oncogenic functions .

What is the relationship between RPS27A and tumor immune microenvironment?

RPS27A displays complex and context-dependent relationships with immune cell populations across different cancer types:

• Immune cell associations: RPS27A expression shows:

  • Positive correlation with B cells, CD4+ T cells, CD8+ T cells, neutrophils, macrophages, and dendritic cells in multiple tumor types

  • Negative correlation with these same immune cell types in other cancers

• Cancer-specific immune profiles:

  • In hepatocellular carcinoma (LIHC): RPS27A positively associates with markers of general T cells, CD8+ T cells, B cells, monocytes, tumor-associated macrophages (TAMs), neutrophils, dendritic cells, Th1 cells, and T cell exhaustion

  • In stomach adenocarcinoma (STAD): RPS27A negatively correlates with markers of TAMs, M2 macrophages, and regulatory T cells (Tregs)

• Spatial relationships: In breast cancer, spatial transcriptomic data demonstrates that RPS27A expression regions overlap with macrophage marker CD68 and myeloid-derived suppressor cell (MDSC) marker CSF1R

This evidence collectively suggests that RPS27A plays a significant role in shaping the tumor immune microenvironment, with important implications for immunotherapy response.

How does RPS27A influence macrophage polarization in cancer?

Experimental evidence has established that RPS27A significantly impacts macrophage polarization, particularly in hepatocellular carcinoma:

• M2 polarization: RPS27A overexpression in HCC cells accelerates M2 polarization of macrophages, as demonstrated through coculturing assays

• Methodological approach: This phenomenon can be studied using:

  • Coculturing of RPS27A-overexpressing cancer cells with macrophages

  • Assessment of M1/M2 markers to determine polarization status

  • Spatial transcriptomics to map RPS27A and macrophage marker colocalization

The promotion of M2 macrophage polarization is particularly significant as M2 macrophages typically create an immunosuppressive environment that facilitates tumor progression. This mechanism may partially explain how RPS27A contributes to cancer development and potentially resistance to certain immunotherapies.

What is the potential value of RPS27A in cancer prognosis and immunotherapy?

RPS27A shows considerable promise as both a prognostic biomarker and potential immunotherapy target:

• Prognostic value: RPS27A expression correlates with clinicopathologic features and survival outcomes across multiple cancer types

• Immunotherapy relevance: RPS27A expression is connected to:

  • Immune subtypes and tumor purity

  • Immune cell infiltration patterns

  • Regulation of immunotherapy response

• Potential therapeutic applications:

  • As a biomarker to stratify patients for immunotherapy

  • As a target to reprogram the tumor immune microenvironment

  • As a component of combination strategies with immune checkpoint inhibitors

Research validating RPS27A as an immunotherapy target would benefit from integrating genomic, transcriptomic, and proteomic approaches with functional validation in preclinical models and correlation with clinical outcomes in patient cohorts.

How does RPS27A influence signaling pathways relevant to cancer research?

RPS27A affects multiple signaling cascades critical for cancer development and progression:

• DNA repair pathways: RPS27A influences DNA repair mechanisms, potentially affecting genomic stability and therapy response

• Invasion and metastasis signaling: Experimental evidence shows RPS27A promotes migration and invasion capabilities in cancer cells

• Immune signaling networks:

  • IL10 synthesis: RPS27A affects IL10 pathways, which are critical for immunomodulation

  • MAPK activation: RPS27A influences this key pathway involved in cell proliferation, differentiation, and survival

These diverse effects on signaling networks position RPS27A as a multifunctional regulator in cancer biology, suggesting that targeting RPS27A might simultaneously affect multiple cancer hallmarks.

What genomic alterations are associated with RPS27A in human cancers?

RPS27A participates in the regulation of genomic alterations with important implications for cancer heterogeneity:

• Tumor mutation burden (TMB): RPS27A expression correlates with TMB, which is a key determinant of immunotherapy response

• Microsatellite instability (MSI): RPS27A shows associations with MSI status across cancer types

• Neoantigen formation: RPS27A affects neoantigen profiles, which influence immune recognition of tumor cells

Understanding these genomic relationships requires integrative approaches combining next-generation sequencing technologies with functional validation studies. The associations with TMB, MSI, and neoantigens are particularly significant given the importance of these features in predicting response to immune checkpoint blockade therapies.

What are the key methodological considerations for studying RPS27A in cancer research?

When designing experiments to investigate RPS27A functions, researchers should consider:

• Expression analysis approaches:

  • Pan-cancer analysis using multiple public platforms (UALCAN, HPA, TISIDB, TIMER, cBioPortal, cancerSEA, TIDE, TIMSO)

  • Immunohistochemistry for protein-level detection in tissue samples

  • RNA-sequencing and qPCR for transcript-level analysis

• Functional validation methods:

  • Overexpression studies: To assess oncogenic potential

  • Coculturing assays: To study immune cell interactions

  • Animal models: For in vivo validation

• Spatial analysis techniques:

  • Spatial transcriptomics: To analyze colocalization with immune markers

  • Multiplex immunofluorescence: To visualize RPS27A and immune cell distribution

These methodological considerations ensure comprehensive characterization of RPS27A's complex functions in cancer and immune regulation.

How can researchers effectively modulate RPS27A for functional studies?

For functional investigations of RPS27A, researchers can employ several approaches:

• Overexpression systems:

  • Plasmid-based expression in cell lines

  • Inducible expression systems for temporal control

  • Viral vector delivery for efficient transduction

• Knockdown/knockout strategies:

  • siRNA or shRNA for transient or stable knockdown

  • CRISPR-Cas9 for complete knockout

  • Degradation-based approaches (PROTACs, etc.) for protein-level depletion

• Domain-specific manipulations:

  • Separating ubiquitin and ribosomal protein functions

  • Mutating specific domains (e.g., zinc finger domains)

  • Using recombinant protein fragments for competition assays

These approaches allow researchers to dissect the distinct functions of RPS27A and its contributions to cancer-related processes.

What considerations are important when using recombinant RPS27A proteins in experimental validation?

When utilizing recombinant RPS27A proteins for experimental validation:

• Protein fragment selection: Consider using defined fragments like RPS27A (aa 94-155) that represent functional domains

• Blocking experiments: For antibody validation, use a 100x molar excess of the protein fragment control based on concentration and molecular weight, pre-incubating the antibody-protein control fragment mixture for 30 minutes at room temperature

• Cross-species considerations: Take advantage of the high sequence identity between human RPS27A and orthologs from model organisms (98% with mouse and rat), which facilitates translational research

• Application-specific optimization: Adjust protocols for specific applications such as IHC/ICC and Western blotting to ensure optimal results

Proper use of recombinant proteins can significantly enhance the reliability and interpretability of experimental results in RPS27A research.

What are the most promising avenues for translational research on RPS27A?

Based on current evidence, several translational research directions for RPS27A show particular promise:

• Biomarker development:

  • Validation of RPS27A as a prognostic biomarker across cancer types

  • Evaluation of RPS27A as a predictive biomarker for immunotherapy response

  • Development of clinical assays for RPS27A assessment

• Therapeutic targeting:

  • Small molecule inhibitors of RPS27A functions

  • Approaches to modulate RPS27A-dependent macrophage polarization

  • Combination strategies with established immunotherapies

• Mechanistic investigations:

  • Detailed characterization of RPS27A's role in specific immune cell populations

  • Elucidation of the molecular mechanisms connecting RPS27A to cancer hallmarks

  • Investigation of synthetic lethal interactions with RPS27A

These research directions reflect the multifaceted roles of RPS27A in cancer biology and immunology, suggesting diverse applications in cancer management.

How might RPS27A research inform combination immunotherapy strategies?

RPS27A's connections to immune regulation suggest several potential applications in combination immunotherapy:

• Macrophage-directed combinations: Given RPS27A's role in M2 macrophage polarization, combining RPS27A targeting with macrophage-reprogramming strategies (e.g., CSF1R inhibitors) may enhance anti-tumor immunity

• T cell checkpoint combinations: RPS27A's associations with T cell exhaustion markers suggest potential synergy with PD-1/PD-L1 or CTLA-4 blockade

• Biomarker-guided approaches: Using RPS27A expression to stratify patients for specific immunotherapy combinations based on predicted immune microenvironment characteristics

Research in this area would benefit from preclinical models evaluating combination efficacy and mechanisms, followed by carefully designed clinical trials with appropriate biomarker analyses.

What are the challenges in targeting RPS27A therapeutically, given its fundamental cellular roles?

Therapeutic targeting of RPS27A presents several significant challenges that researchers must address:

• Dual functionality concerns: As RPS27A functions in both protein synthesis (ribosomal component) and protein degradation (ubiquitin source), complete inhibition may disrupt essential cellular processes

• Specificity requirements: Strategies must selectively target cancer-specific functions of RPS27A while sparing normal cellular functions

• Delivery challenges: Approaches must effectively deliver therapeutics to tumor cells while minimizing exposure in normal tissues with high protein synthesis requirements

• Resistance mechanisms: Cancer cells may develop compensatory mechanisms to overcome RPS27A targeting, requiring combination approaches

Addressing these challenges will require sophisticated drug development strategies, potentially including targeted delivery systems, selective modulators of specific RPS27A functions, and carefully designed combination approaches to manage potential resistance.