Recombinant Human Transmembrane protein C16orf54 (C16orf54)

What is C16orf54 and where is it primarily expressed?

C16orf54 (Chromosome 16 open reading frame 54) is a protein-coding gene that encodes a transmembrane protein predicted to be an integral component of cell membranes . Recent studies have revealed that C16orf54 shows biased expression in several tissues, with particularly notable presence in the bone marrow, lymph nodes, and at least 11 other tissue types throughout the human body . Within the immune system, C16orf54 has been specifically identified on naive and activated CD4+ T cells, making it relevant to immunological research . The protein has been characterized through multi-omic approaches, including proteomic techniques (PAL-qLC-MS/MS), targeted flow cytometry screens, and genome-wide microarray expression analysis . These comprehensive analyses have contributed to our understanding of C16orf54 as part of the surface proteome of immune cells, particularly T lymphocytes, where it may play roles in cellular communication and immune function.

How does C16orf54 expression change during CD4+ T cell activation?

The expression pattern of C16orf54 during CD4+ T cell activation has been investigated through time course experiments that mimic T cell receptor engagement. Research has shown that C16orf54 is expressed on both naive CD4+ T cells and maintains expression following activation with anti-CD3/anti-CD28 stimulation . The comprehensive surface atlas of human naive and activated CD4+ T cells, which identified and quantified 229 cell surface proteins and detected 927 cell surface protein-coding transcripts, includes valuable data on C16orf54 expression dynamics . While specific fold-changes in expression levels between naive and activated states are not detailed in the available search results, the continued presence of C16orf54 on activated CD4+ T cells suggests it may have functional relevance throughout the T cell activation process. Understanding these expression changes is particularly important when considering the role of CD4+ T cells in orchestrating immune responses and their involvement in autoimmune diseases and allergic conditions, where C16orf54 might represent a potential therapeutic target.

What are the structural characteristics of the C16orf54 protein?

C16orf54 is classified as a transmembrane protein that is predicted to be an integral component of the cell membrane . Although detailed structural information is limited in the available search results, the protein has been studied using various techniques including Western blot and flow cytometry, which have confirmed its expression on the cell surface . To facilitate structural and functional studies, researchers have developed expression systems for recombinant forms of C16orf54, including both membrane-bound versions expressed in mammalian cells and soluble forms produced in insect cells . The successful generation of monoclonal antibodies against human and murine C16orf54 suggests the presence of accessible epitopes that can be targeted for detection and potentially for therapeutic interventions . Additional structural insights might be gleaned from further proteomics studies and crystallography work, which would be valuable for understanding protein-protein interactions and potential signaling functions of C16orf54 in immune and cancer contexts.

What techniques are effective for detecting C16orf54 expression in different cell types?

Multiple complementary techniques have proven effective for detecting C16orf54 expression across various cell types. Flow cytometry using specific monoclonal antibodies represents a primary method for analyzing C16orf54 surface expression on immune cells, allowing for quantitative assessment at the single-cell level . Researchers have generated and validated both anti-human and anti-mouse C16orf54 antibodies through peptide immunization of rats and mice followed by hybridoma generation, with subsequent antibody specificity confirmed via ELISA using biotinylated peptides . Western blot analysis provides another approach for C16orf54 protein detection, with specific hybridoma supernatants screened for suitability in this application . At the transcriptional level, quantitative PCR (qPCR) has been employed to validate C16orf54 expression identified in genomic screenings . For comprehensive proteomic identification, PAL-qLC-MS/MS (Periodate Oxidation and Aniline-Catalyzed Oxime Ligation coupled with quantitative liquid chromatography-tandem mass spectrometry) has successfully detected C16orf54 among other cell surface glycoproteins . Additionally, immunoprecipitation of recombinant C16orf54 has been used to isolate and study the protein in experimental systems .

How can recombinant C16orf54 be produced for experimental applications?

Production of recombinant C16orf54 for experimental applications involves several established methodologies detailed in the research literature. Researchers have successfully generated expression systems for both membrane-bound and soluble forms of C16orf54 using different host systems . For membrane-bound versions, mammalian expression systems have been employed following cloning of the C16orf54 sequence into appropriate overexpression vectors . The process typically begins with amplification of the C16orf54 insert using PCR, followed by ligation into expression vectors and transformation into competent bacteria for plasmid amplification . After verification through colony PCR and plasmid isolation, the constructs are transfected into mammalian cells for protein expression . For soluble forms of C16orf54, which may be more suitable for certain biochemical assays and structural studies, insect cell expression systems have been utilized, followed by purification protocols to isolate the recombinant protein . The methodology might involve affinity tags like His-tags or Fc-fusion approaches to facilitate purification. To verify successful expression and purification, techniques such as Western blotting with anti-C16orf54 antibodies and mass spectrometry have been applied .

What controls should be included when studying C16orf54 in functional assays?

When designing functional assays to investigate C16orf54, several critical controls must be incorporated to ensure experimental validity and interpretability of results. For antibody-based detection systems, isotype controls matched to the species and immunoglobulin class of the anti-C16orf54 antibody are essential to account for non-specific binding . Peptide competition assays, where soluble peptides used for immunization are pre-incubated with the antibody before cell staining, provide important controls to confirm antibody specificity . In overexpression studies, empty vector transfections serve as necessary controls to distinguish effects specific to C16orf54 from those resulting from the transfection process itself . For functional studies examining the role of C16orf54 in cellular processes, CRISPR/Cas9-mediated knockout approaches have been implemented, requiring control sgRNAs targeting non-relevant genomic regions to control for off-target effects of the CRISPR system . When studying C16orf54 in the context of T cell activation, appropriate time course controls must be included to account for temporal changes in the T cell activation state . Additionally, for purified recombinant C16orf54 protein used in binding or functional studies, heat-denatured protein controls help distinguish specific biological activities from non-specific effects.

How does C16orf54 expression correlate with cancer prognosis and diagnosis?

C16orf54 expression has emerged as a potential prognostic and diagnostic marker across multiple cancer types according to comprehensive pan-cancer analyses. Research utilizing data from The Cancer Genome Atlas (TCGA), Cancer Cell Line Encyclopedia (CCLE), and Genotype-Tissue Expression (GTEx) has revealed that C16orf54 is typically expressed at low levels in most cancer types . Despite this low expression, C16orf54 has demonstrated high accuracy in distinguishing between cancerous and normal tissues in numerous cancer types, suggesting potential utility as a diagnostic biomarker . The prognostic significance of low C16orf54 mRNA levels varies across different cancer types, indicating that its role in cancer progression may be context-dependent . Furthermore, C16orf54 expression shows positive correlations with stromal, immune, and ESTIMATE scores, which are computational metrics used to predict the presence of infiltrating stromal and immune cells in tumor tissues . Interestingly, C16orf54 expression typically displays a negative correlation with tumor purity, suggesting that higher expression might be associated with increased non-cancerous components within the tumor microenvironment .

What is the relationship between C16orf54 and the tumor immune microenvironment?

The relationship between C16orf54 and the tumor immune microenvironment appears to be significant based on comprehensive bioinformatic analyses of cancer datasets. Studies have demonstrated that C16orf54 expression positively correlates with immune cell infiltration in most cancer types, suggesting it may play a role in modulating the immune response within tumors . Specifically, C16orf54 expression shows positive associations with various immune regulatory genes, including chemokines, receptors, major histocompatibility complexes, and both immune inhibitory and stimulatory genes . These correlations indicate that C16orf54 may be involved in regulating immune cell recruitment, activation, or function within the tumor microenvironment. Functional pathway analyses using Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Set Enrichment Analysis (GSEA) have further revealed that C16orf54 expression is closely linked to signaling pathways of immune cells and factors . Given its original identification on CD4+ T cells and other immune cells, these findings suggest C16orf54 may represent a bridge between cancer cells and immune components in the tumor microenvironment, potentially influencing anti-tumor immunity or immunosuppression depending on the cancer context.

How might C16orf54 be utilized as a target for cancer immunotherapy?

C16orf54 presents several characteristics that make it a promising candidate for cancer immunotherapy strategies based on recent research findings. Integrated analysis of C16orf54 across multiple cancers has identified it as a potential target for adjuvant immunotherapy approaches . Its differential expression between normal and cancerous tissues provides a potential window for therapeutic intervention with minimal off-target effects on healthy tissues . The positive correlation between C16orf54 expression and immune cell infiltration suggests that targeting this protein might enhance anti-tumor immune responses or overcome immunosuppression in the tumor microenvironment . Additionally, C16orf54 expression has been significantly associated with tumor heterogeneity indicators, including tumor mutation burden (TMB) and microsatellite instability (MSI), as well as with tumor stemness indicators DNAss and RNAss . These associations suggest that C16orf54-targeted approaches might address particularly challenging aspects of cancer biology like tumor heterogeneity and cancer stem cell populations. Potential immunotherapeutic strategies could include antibody-drug conjugates targeting C16orf54, chimeric antigen receptor (CAR) T-cell approaches, or bispecific antibodies linking C16orf54-expressing cells to cytotoxic immune effectors.

What are the functional consequences of C16orf54 knockout or overexpression in immune cells?

The functional consequences of C16orf54 genetic manipulation in immune cells represent a crucial area for understanding its biological significance, though detailed phenotypic information remains limited in current literature. Researchers have developed CRISPR/Cas9-mediated knockout mouse models targeting C16orf54, indicating the importance of studying its function through loss-of-function approaches . These models likely facilitate investigation of immune cell development, activation, and effector functions in the absence of C16orf54 expression. Complementary to knockout strategies, overexpression systems for recombinant C16orf54 have been established in mammalian cells, enabling gain-of-function studies to assess the impact of elevated C16orf54 levels on immune cell behavior . Potential functional consequences of C16orf54 modulation might include alterations in T cell activation thresholds, proliferation rates, cytokine production profiles, or migration capabilities. The development of both stable cell lines expressing C16orf54 and C16orf54 knockout models suggests interest in addressing these functional questions through comprehensive immunological assays . Additionally, the generation of soluble forms of C16orf54 in insect cells indicates possible investigations into whether the extracellular domain of C16orf54 has independent functional activities or competitive inhibitory effects when separated from its transmembrane anchor .

What protein-protein interactions does C16orf54 engage in, and how do these inform its function?

The protein-protein interaction network of C16orf54 remains largely uncharacterized in current research literature, representing a critical knowledge gap that would substantially inform understanding of its function. As a transmembrane protein predicted to be an integral component of the cell membrane, C16orf54 is positioned to engage in interactions with both extracellular binding partners and intracellular signaling molecules . Techniques for investigating these interactions may include immunoprecipitation followed by mass spectrometry to identify binding partners, approaches that have been technically established for recombinant C16orf54 . The generation of monoclonal antibodies against human and murine C16orf54 provides tools that could be employed in co-immunoprecipitation experiments to pull down native protein complexes from primary immune cells or cell lines . Its presence on the surface of both naive and activated CD4+ T cells suggests potential interactions with antigen-presenting cells or extracellular matrix components during immune responses . Additionally, bioinformatic analyses revealing correlations between C16orf54 expression and various immune regulatory genes, including chemokines and their receptors, could provide computational predictions of potential interaction partners that could be experimentally validated . Understanding these protein-protein interactions would significantly advance knowledge of how C16orf54 integrates into cellular signaling networks and contributes to immune cell function.

How can C16orf54 be leveraged as a biomarker in clinical diagnostics?

The potential of C16orf54 as a biomarker in clinical diagnostics is supported by several findings from cancer research and immunology studies. Comprehensive analyses across multiple cancer types have demonstrated that C16orf54 expression can distinguish between cancer and normal tissues with high accuracy, suggesting utility as a diagnostic marker . The differential expression patterns of C16orf54 across various cancer types provide a foundation for developing tissue-specific diagnostic approaches that could complement existing biomarkers . Additionally, C16orf54's expression on immune cells, particularly CD4+ T cells, indicates potential applications in monitoring immune status in conditions such as autoimmune diseases, allergies, or immunodeficiencies . Methodologically, detection of C16orf54 could be implemented through various clinical laboratory techniques, including immunohistochemistry on tissue samples, flow cytometry on blood or bone marrow specimens, or potentially through analysis of soluble C16orf54 in serum if shed forms exist . The development and validation of clinical-grade monoclonal antibodies against C16orf54 would be essential for standardizing such diagnostic applications . Furthermore, correlations between C16orf54 expression and tumor heterogeneity markers (TMB, MSI) suggest it could serve as a companion diagnostic to identify patients who might benefit from specific immunotherapy approaches or precision oncology interventions .

What therapeutic modalities targeting C16orf54 show the most promise for clinical development?

Several therapeutic modalities targeting C16orf54 show potential for clinical development based on its biological characteristics and expression patterns. Monoclonal antibody therapies represent a primary approach, given the successful generation of antibodies against both human and murine C16orf54 and their validated specificity in various assays . These antibodies could be developed as naked antibodies with effector functions, antibody-drug conjugates delivering cytotoxic payloads to C16orf54-expressing cells, or as bispecific antibodies linking C16orf54-positive cells to immune effectors. For immune-related conditions, antibodies with immunomodulatory properties (agonistic or antagonistic) might be developed to modify C16orf54-mediated signaling . Cell-based immunotherapies, such as chimeric antigen receptor (CAR) T cells targeting C16orf54, could exploit its differential expression in certain disease states, particularly in hematological malignancies given its expression in immune cell populations . Small molecule approaches targeting C16orf54 signaling pathways identified through KEGG and GSEA analyses offer another avenue for therapeutic development . Additionally, the generation of CRISPR/Cas9 knockout systems for C16orf54 provides proof-of-concept for potential gene editing therapies in appropriate clinical contexts . The reported correlations between C16orf54 expression and immune cell infiltration in tumors further suggest that C16orf54-targeting strategies might be particularly effective when combined with existing immunotherapies like checkpoint inhibitors .

What are the potential off-target effects or toxicities to consider when targeting C16orf54 therapeutically?

When developing therapeutic approaches targeting C16orf54, several potential off-target effects and toxicities must be carefully considered based on its expression pattern and biological functions. Given that C16orf54 shows biased expression in bone marrow, lymph nodes, and at least 11 other tissues, targeting this protein could potentially affect multiple organ systems beyond the intended therapeutic site . Particularly concerning would be effects on normal immune cell populations, as C16orf54 is expressed on naive and activated CD4+ T cells and potentially other immune cells . Therapeutic modalities targeting C16orf54 might therefore risk compromising normal immune function, potentially leading to immunosuppression, increased infection susceptibility, or dysregulated immune responses against self-antigens. The development of antibody-based therapeutics would require extensive cross-reactivity testing to ensure specificity for human C16orf54 without binding to structurally similar proteins . For cell-based therapies like CAR-T cells targeting C16orf54, cytokine release syndrome could present a significant risk given the protein's expression across multiple immune cell populations . Additionally, since C16orf54 expression correlates with various immune regulatory genes and signaling pathways, therapeutic interventions might disrupt delicately balanced immune networks with unpredictable consequences . Preclinical evaluation in appropriate animal models, including the C16orf54 knockout mice that have been generated, would be essential for identifying potential toxicities before clinical translation .

How conserved is C16orf54 across species, and what does this suggest about its functional importance?

The evolutionary conservation of C16orf54 across species provides important insights into its functional significance, though detailed comparative analysis is limited in the current search results. The development of research tools for both human and murine versions of C16orf54, including species-specific monoclonal antibodies and expression systems, indicates sufficient conservation between these mammals to warrant parallel investigation . The generation of CRISPR/Cas9-mediated knockout mouse models further suggests that murine C16orf54 shares enough functional and structural similarities with its human counterpart to serve as a valuable model system for studying its biological roles . The successful isolation of murine naive CD4+ T cells for C16orf54 expression analysis indicates conservation of its presence in this immune cell population across species . Highly conserved proteins typically play fundamental biological roles that have been maintained through evolutionary pressure, suggesting C16orf54 may have important functions in cellular processes common to multiple species. The development of expression systems in both mammalian and insect cells further demonstrates the protein's ability to be recognized and processed by evolutionarily diverse cellular machinery . A more comprehensive phylogenetic analysis across additional species would provide greater insight into the evolutionary history of C16orf54 and potentially reveal functional domains of highest conservation that might represent critical regions for protein-protein interactions or signaling functions.

Are there paralogs or protein family members related to C16orf54, and how do they compare functionally?

The identification of paralogs or protein family members related to C16orf54 would provide valuable comparative insights into its function, though the current search results do not explicitly address this aspect of C16orf54 biology. As a transmembrane protein predicted to be an integral component of the cell membrane, C16orf54 may share structural or functional similarities with other membrane-spanning proteins involved in cellular signaling or transport . Bioinformatic approaches such as sequence homology analysis, structural prediction algorithms, or motif identification could potentially reveal related proteins that might form a functional family. The designation of the protein as "C16orf54" (Chromosome 16 open reading frame 54) indicates it was initially identified based on genomic location rather than functional classification, suggesting that homologous proteins might exist but have not yet been grouped into a formal protein family . Comparative functional studies between C16orf54 and any identified paralogs would be particularly valuable for understanding redundancy or specialization within a potential protein family. Such comparisons might include expression pattern analysis across tissues, response to cellular activation signals, protein-protein interaction networks, and phenotypic consequences of genetic manipulation. The development of research tools for C16orf54, such as monoclonal antibodies and expression systems, provides methodological approaches that could be adapted to study related proteins once identified .

What are the most critical unanswered questions about C16orf54 that require further investigation?

Despite significant progress in characterizing C16orf54, numerous critical questions remain unanswered and warrant dedicated research efforts. Perhaps most fundamental is elucidating the precise biological function of C16orf54 in immune cells, particularly CD4+ T cells where it has been well-documented . The molecular mechanisms through which C16orf54 influences cellular behavior, including potential ligands, signaling pathways, and downstream effectors, remain largely unknown and represent crucial knowledge gaps . The phenotypic consequences of C16orf54 knockout in vivo, particularly regarding immune system development and function, require thorough investigation using the CRISPR/Cas9 knockout mouse models that have been developed . Additionally, the regulation of C16orf54 expression under various physiological and pathological conditions, including different inflammatory states, infection scenarios, and malignant transformation, needs systematic characterization. The potential role of C16orf54 in autoimmune diseases and allergies, conditions where CD4+ T cell dysfunction plays a central role, represents another important area for investigation . From a cancer perspective, understanding the mechanisms underlying the correlations between C16orf54 expression and tumor immune infiltration, heterogeneity, and stemness would provide valuable insights for potential therapeutic applications . Finally, determining whether C16orf54 has different functions across the various tissues where it is expressed or whether it maintains consistent roles across diverse cellular contexts would significantly advance our understanding of this intriguing protein.

What emerging technologies could accelerate our understanding of C16orf54 biology?

Several cutting-edge technologies could substantially accelerate our understanding of C16orf54 biology by addressing current knowledge gaps and enabling more sophisticated functional analyses. Single-cell multi-omics approaches combining transcriptomics, proteomics, and epigenomics could provide unprecedented resolution of C16orf54 expression patterns across cell types and states, revealing subtle dynamics invisible to bulk analysis techniques . CRISPR screening methodologies, particularly those employing domain-specific editing or activation/repression systems, could systematically dissect functional regions of C16orf54 and identify genetic interactions . Spatial transcriptomics and proteomics would enable visualization of C16orf54 expression within tissue microenvironments, providing crucial context for understanding its function in complex multicellular systems like lymphoid organs or tumors . Advanced protein structure determination methods, including cryo-electron microscopy and AlphaFold-based computational prediction, could reveal the three-dimensional structure of C16orf54, informing hypotheses about protein-protein interactions and signaling mechanisms . Mass spectrometry-based interactomics using proximity labeling approaches like BioID or APEX could map the protein interaction network of C16orf54 in living cells under various conditions . Intravital imaging of fluorescently tagged C16orf54 in animal models would allow real-time visualization of its dynamics during immune responses or tumor development . Finally, patient-derived organoids or humanized mouse models could bridge fundamental biology with clinical relevance, enabling testing of C16orf54-targeted therapies in systems closely mimicking human disease .