TMEM205 Antibody

What is TMEM205 and where is it predominantly expressed?

TMEM205 is a 189 amino acid transmembrane protein that spans biological membranes. The protein is encoded by the TMEM205 gene located on human chromosome 19, which contains approximately 63 million bases and represents more than 2% of the human genome . Expression profiling of normal human tissues reveals differential expression patterns with significantly higher expression in the liver, pancreas, and adrenal glands . In cancer cells, TMEM205 plays a critical role in resistance to the chemotherapeutic agent cisplatin .

What types of TMEM205 antibodies are currently available for research?

Several types of TMEM205 antibodies are available for research applications:

These antibodies are available in various formats including unconjugated forms and conjugated versions with HRP, PE, FITC, and multiple Alexa Fluor® conjugates . Researchers should select antibodies based on their specific experimental requirements and target species .

How can I validate a TMEM205 antibody for my research?

Thorough validation of TMEM205 antibodies should include:

• Testing in multiple applications (WB, IHC, IF) using recommended protocols

• Using positive controls with known high TMEM205 expression (liver, pancreas tissue lysates)

• Confirming the correct molecular weight band (predicted 21 kDa) in Western blots

• Including appropriate negative controls

• Testing cell lines with established TMEM205 expression (RT4, U-251 MG, MCF7)

• Considering peptide competition assays using available neutralizing peptides

Western blot analysis using validated antibodies should show the predicted 21 kDa band in appropriate samples . For immunohistochemistry, validated results show specific staining in tissues like urinary bladder, and for immunofluorescence, specific cellular localization patterns can be observed in cell lines like MCF7 .

How does TMEM205 contribute to cisplatin resistance in cancer cells?

TMEM205's role in cisplatin resistance involves several mechanisms:

• TMEM205 was first identified through functional cloning from a retroviral cDNA library derived from human cisplatin-resistant cells .

• The protein is located at the cell surface and its expression is significantly increased in cisplatin-selected resistant cell lines, as demonstrated by immunoblotting, confocal examination, and immuno-electron microscopy .

• Stable transfection of the TMEM205 gene confers approximately 2.5-fold resistance to cisplatin .

• Mechanistically, TMEM205 appears to reduce cisplatin accumulation in cells, as demonstrated by uptake assays with Alexa Fluor-cisplatin showing reduced accumulation in cisplatin-resistant KB-CP.3 and KB-CP.5 cells, and in TMEM205-transfected cells .

• TMEM205, in conjunction with Rab 8, may contribute to this resistance by expelling chemotherapeutic agents from cells, making treatment less effective .

Understanding these mechanisms could lead to strategies for overcoming drug resistance in cancer therapy.

What is the relationship between TMEM205 expression and immune cell populations in hepatocellular carcinoma?

Research using RNA-seq data from The Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium (ICGC) has revealed significant correlations between TMEM205 expression and immune cell populations in HCC:

• TMEM205 expression positively correlates with the proportion of macrophages in tumor tissues (Pearson r = 0.45, p < 0.0001) .

• Negative correlations exist between TMEM205 expression and M2 macrophage markers (CD163, EGR2, and MS4A4A) .

• TMEM205 expression negatively correlates with regulatory T cell (Treg) markers (CCR8, STAT5B, and IL2RA) .

• A positive correlation exists between TMEM205 expression and the proportion of CD8+ T cells (Pearson r = 0.26, p < 0.0001) .

• TMEM205 expression negatively correlates with IL-10 expression (Pearson r = -0.22, p < 0.0001) .

These findings suggest TMEM205 might improve HCC patients' prognosis by reducing immunosuppressive cells (M2 macrophages and Tregs) and facilitating cytotoxic T cell infiltration into the tumor microenvironment .

What methodological approaches are recommended for studying TMEM205's role in the tumor microenvironment?

To effectively study TMEM205's role in the tumor microenvironment, researchers should consider:

• Comprehensive transcriptomic analysis: RNA-seq of tumor tissues to correlate TMEM205 expression with immune-related genes and pathways .

• Immune cell quantification: Using tools like the Estimate the Proportion of Immune and Cancer cells (EPIC) to estimate the proportions of various immune cells in tumor tissues .

• Multiplex immunofluorescence: To visualize TMEM205 alongside immune cell markers in tissue sections.

• Correlation analyses: Statistical approaches to identify associations between TMEM205 expression and immune cell markers .

• In vitro models: Co-culture systems to study interactions between TMEM205-expressing cancer cells and immune cells.

• CRISPR technologies: Using TMEM205 CRISPR/Cas9 knockout plasmids and CRISPR activation plasmids to modulate expression levels in experimental models .

• Patient-derived xenografts: To study TMEM205 in more clinically relevant settings.

These approaches can help elucidate how TMEM205 influences the composition and function of immune cells within the tumor microenvironment.

How does TMEM205 expression correlate with patient outcomes in hepatocellular carcinoma?

Multiple studies have established TMEM205 as a prognostic marker in HCC:

These consistent results across independent cohorts establish TMEM205 as a robust prognostic biomarker in HCC.

How might TMEM205 be incorporated into combination therapy approaches?

TMEM205's dual roles in drug resistance and immune modulation suggest several potential approaches for combination therapy:

• Chemosensitization strategies: Targeting TMEM205 could potentially reverse cisplatin resistance, improving the efficacy of platinum-based chemotherapies .

• Immunotherapy enhancement: Given TMEM205's association with favorable immune cell profiles, combining TMEM205-targeted therapies with checkpoint inhibitors (e.g., anti-PD-1/PD-L1) might improve response rates .

• Biomarker-guided therapy: TMEM205 expression levels could help select patients for specific combination approaches, similar to how recent studies found that anti-PD-1 (atezolizumab) combined with anti-VEGF (bevacizumab) showed encouraging antitumor activity in unresectable HCC .

• Novel immunomodulatory approaches: Since TMEM205 appears to influence the balance of immunosuppressive cells (M2 macrophages and Tregs) and cytotoxic T cells, therapies that enhance this effect could create a more favorable tumor microenvironment .

The potential of TMEM205 as both a biomarker and therapeutic target makes it a valuable focus for developing next-generation combination therapies for cancer.

What are the optimal experimental conditions for detecting TMEM205 using Western blotting?

For optimal Western blot detection of TMEM205:

• Sample preparation: RIPA buffer is suitable for protein extraction from tissues and cell lines .

• Loading amount: 35μg for tissue lysates has been validated for some antibodies .

• Expected molecular weight: Look for bands at the predicted size of 21 kDa .

• Antibody dilutions: Vary by antibody, for example:

  • ab224516 at 1/100 dilution

  • ab109468 at 0.03 μg/mL

• Incubation time: Primary antibody incubation of 1 hour has been validated for some antibodies .

• Detection method: ECL technique is widely used and validated .

• Positive controls: Consider using lysates from tissues with high expression (liver, pancreas) or cancer cell lines like RT4 (urinary bladder cancer), U-251 MG (brain glioma), or MCF7 (breast adenocarcinoma) .

Western blot analysis can evaluate TMEM205 expression across different tissues and cell lines, enabling comparative studies between normal and disease states.

What methods can be used to study TMEM205's cellular localization and interaction partners?

To investigate TMEM205's cellular localization and interaction network:

• Immunofluorescence/Immunocytochemistry: Several antibodies are validated for IF/ICC, such as ab224516 for staining in PFA-fixed, Triton X-100 permeabilized MCF7 cells .

• Subcellular fractionation: Combined with Western blotting to quantify TMEM205 levels in different cellular compartments.

• Co-immunoprecipitation: Using validated antibodies like sc-390447 (G-1) or sc-514568 (B-5) that are suitable for immunoprecipitation to identify interaction partners .

• Proximity labeling techniques: BioID or APEX2 fusion proteins could identify proteins in close proximity to TMEM205.

• Live-cell imaging: Using fluorescently-tagged TMEM205 to monitor dynamic localization.

• Electron microscopy: Immuno-electron microscopy has been used to detect TMEM205 localization at high resolution in cisplatin-resistant cell lines .

Understanding TMEM205's localization and interaction partners is crucial for deciphering its functional role in drug resistance and immune modulation.

What are the key unanswered questions regarding TMEM205's function in normal and disease states?

Despite progress in understanding TMEM205's role in cancer, several important questions remain:

• Physiological function: What is TMEM205's normal biological role, particularly in organs with high expression (liver, pancreas, adrenal glands)?

• Regulatory mechanisms: What factors control TMEM205 expression in normal and disease states?

• Structure-function relationship: How does TMEM205's structure relate to its function in drug efflux and immune modulation?

• Signaling pathways: What downstream signaling cascades are influenced by TMEM205?

• Role in other cancers: Is TMEM205's prognostic significance and immune correlation in HCC relevant to other cancer types?

• Drug development potential: Can TMEM205 be directly targeted pharmacologically to overcome resistance or enhance immunity?

• Biomarker validation: Can TMEM205 expression reliably predict treatment response in prospective clinical trials?

Addressing these questions will require multidisciplinary approaches and could significantly advance our understanding of cancer biology and treatment strategies.

How might emerging technologies advance our understanding of TMEM205 biology?

Emerging technologies offer new opportunities to explore TMEM205 function:

• Single-cell RNA sequencing: To understand cell-type specific expression patterns and heterogeneity within tumors.

• Spatial transcriptomics: To map TMEM205 expression in relation to different components of the tumor microenvironment.

• CRISPR screening: High-throughput functional genomics to identify genes that interact with TMEM205 in resistance or immune modulation.

• Cryo-EM and structural biology: To determine TMEM205's molecular structure and mechanism of action.

• Organoid models: To study TMEM205 in more physiologically relevant 3D culture systems.

• Patient-derived xenografts: To evaluate TMEM205-targeting approaches in models that better recapitulate human disease.

• AI and machine learning: To identify patterns in complex datasets that might reveal new aspects of TMEM205 biology.

These technologies could accelerate discoveries about TMEM205's biological functions and therapeutic potential in coming years.