Tmem205 Antibody

What is TMEM205 and what are its key structural and functional characteristics?

TMEM205 (Transmembrane Protein 205) is a 189 amino acid protein predicted to be a four-membrane pass protein . It has a molecular mass of approximately 21-22 kDa . TMEM205 is predominantly expressed in the liver, pancreas, and adrenal glands, with lower expression levels in skeletal muscle .

Functionally, TMEM205 plays crucial roles in:

• Cellular signaling processes

• Drug resistance development, particularly against cisplatin

• Membrane protein trafficking, where it co-localizes with Rab8 and Rab11

TMEM205 is encoded by a gene located on human chromosome 19, which encompasses approximately 63 million bases and contains over 1,400 genes, representing more than 2% of the human genome .

What antibody options are available for TMEM205 detection, and what applications are they suitable for?

Several TMEM205 antibody options are available for research purposes:

Many of these antibodies are available in multiple conjugated forms, including:

• Horseradish peroxidase (HRP)

• Phycoerythrin (PE)

• Fluorescein isothiocyanate (FITC)

• Various Alexa Fluor® conjugates

How can researchers validate the specificity of TMEM205 antibodies?

Validating antibody specificity is critical for reliable research. For TMEM205 antibodies, consider these approaches:

• Western blotting with positive and negative controls:

  • Use tissues with known high expression (pancreas, liver) as positive controls

  • Compare against tissues with low expression (skeletal muscle)

  • Expected band size: 21-22 kDa

• Knockdown validation:

  • Use siRNA or shRNA targeting TMEM205

  • Confirm reduced signal in immunoblotting and immunofluorescence

• Subcellular localization verification:

  • Membrane-specific staining should be observed in immunofluorescence

  • Co-localization with known membrane markers

• Peptide competition assays:

  • Pre-incubation with immunizing peptide should eliminate specific staining

  • Some suppliers offer neutralizing peptides specifically for this purpose

How does TMEM205 contribute to cisplatin resistance in cancer cells?

TMEM205 has been identified as a key mediator of cisplatin resistance through several mechanisms:

• Reduced drug accumulation:

  • TMEM205 overexpression correlates with decreased intracellular accumulation of cisplatin

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

  • This effect has been demonstrated using Alexa Fluor-labeled cisplatin uptake assays

• Exosomal drug efflux pathway:

  • TMEM205 contributes to increased exosome release

  • Higher TMEM205 expression correlates with elevated exosome concentration in conditioned media

  • These exosomes may facilitate cisplatin expulsion from cells

• Endocytic trafficking involvement:

  • TMEM205 undergoes ligand-independent constitutive endocytosis

  • It co-localizes with Rab11 in late recycling endosomes

  • This trafficking occurs in a clathrin-independent manner

Research has shown that TMEM205 expression is significantly elevated in ovarian clear cell carcinoma (OCCC) cell lines compared to normal ovary epithelial cells, suggesting its potential role as a biomarker for chemoresistance .

What experimental approaches can be used to study TMEM205 trafficking and localization?

Several sophisticated techniques have been employed to investigate TMEM205 trafficking:

• Antibody feeding assay combined with surface fluorescence quenching:

  • Label surface TMEM205 with anti-TMEM205 antibody and Alexa Fluor 488 secondary Fab

  • Allow internalization at 37°C (typically 90 minutes)

  • Quench remaining surface fluorescence with anti-AF488 quenching antibody

  • Analyze by flow cytometry to quantify internalized protein

• Co-localization studies:

  • Immunofluorescence microscopy with markers for different cellular compartments

  • Particularly useful with Rab protein markers (Rab8, Rab11) to determine endosomal association

  • Confocal microscopy for high-resolution imaging of membrane localization

• Subcellular fractionation:

  • Separate membrane fractions (MF) from nuclear fractions (NF)

  • Run SDS-PAGE and Western blot on fractions

  • TMEM205 should be enriched in membrane fractions (21 kDa band)

• Electron microscopy:

  • Immuno-electron microscopy for precise subcellular localization

  • Gold-labeled antibodies can determine exact membrane distribution

How can researchers effectively modulate TMEM205 expression for functional studies?

To investigate TMEM205 function, researchers can employ several strategies:

• Gene silencing approach:

  • siRNA or shRNA targeting TMEM205

  • Select clones with verified knockdown at both RNA and protein levels

  • Example: The OVTMSi1 clone has been successfully used in OVTOKO cells

  • Validate knockdown efficiency using qRT-PCR and Western blot

• Overexpression systems:

  • Full-length cDNA transfection (e.g., MGC110858 clone, Accession BC091472)

  • Insert into mammalian expression vectors (e.g., pcDNA5.1)

  • Use lipid-based transfection methods (e.g., Lipofectin)

  • Generate stable transfectants with appropriate selection markers (G418)

• Functional validation assays:

  • Cisplatin sensitivity testing (clonogenic assays)

  • Drug accumulation studies using fluorescently-labeled cisplatin

  • Exosome isolation and quantification from conditioned media

• In vivo models:

  • Xenograft models with TMEM205-modulated cancer cells

  • Combination therapy approaches (e.g., oncolytic virus and cisplatin)

What is the relationship between TMEM205 and exosomal pathways in drug resistance?

Recent research has established an important connection between TMEM205 and exosomal pathways in drug resistance:

• Exosome characterization:

  • Exosomes can be isolated from conditioned media using methods like Vn96-based ME kits

  • Confirmation of proper exosome isolation requires:

    • Nanoparticle Tracking Analysis (NTA) for size distribution

    • Image Stream Flow cytometry (ISF)

    • Cryo TEM for ultrastructural confirmation

• TMEM205 impact on exosome release:

  • TMEM205 silencing significantly reduces exosome concentration in conditioned media

  • Control OVTOKO cells and scrambled siRNA transfected cells show higher exosome levels compared to TMEM205-silenced cells

• Cisplatin efflux via exosomes:

  • Cells treated with cisplatin (20 μM) in FBS-free media release exosomes

  • TMEM205 appears to facilitate this process, potentially contributing to drug resistance

  • Targeting this pathway may provide therapeutic opportunities

• Mechanistic interactions:

  • TMEM205 interacts with glycoprotein-C of oncolytic herpes simplex virus (oHSV)

  • Both proteins undergo ubiquitination and are shuttled outside the cell via exosomes

  • This process can be exploited therapeutically

What therapeutic strategies can overcome TMEM205-mediated chemoresistance?

Research has identified promising approaches to overcome TMEM205-mediated chemoresistance:

• Oncolytic virus (oHSV) combination therapy:

  • Pre-treatment with oHSV followed by cisplatin treatment shows synergistic effects

  • This combination decreases TMEM205 expression and sensitizes cells to cisplatin

  • Optimal conditions identified: oHSV at MOI of 1 followed by cisplatin at 10 μM

• Mechanistic basis for combination therapy:

  • oHSV infection affects cellular accumulation of cisplatin

  • This can be demonstrated using Texas red-conjugated cisplatin

  • The interaction between oHSV glycoprotein-C and TMEM205 is central to this effect

• Validation experiments:

  • Sulforhodamine B (SRB) assays confirm synergistic effects

  • Controls with heat-killed oHSV show no significant difference compared to untreated controls

  • This validates that active viral infection is necessary for the observed effects

What are the optimal methods for quantifying TMEM205 expression in clinical and experimental samples?

Researchers can employ several complementary approaches to quantify TMEM205:

• Quantitative real-time PCR (qRT-PCR):

  • Use specific oligonucleotide primers and TaqMan probes

  • Reference sequence: NM_198536

  • TaqMan Gene Expression Assay ID for TMEM205: Hs00414441_m1

  • GAPDH as control (Assay ID: Hs99999905_m1)

  • Synthesis of cDNA using TaqMan Reverse Transcription Reagents (1 μg total RNA/50 μL reaction volume)

• Western blotting:

  • Antibody concentrations: 0.03-0.4 μg/mL

  • Expected band size: 21-22 kDa

  • Use pancreas or liver lysates as positive controls

• Immunohistochemistry:

  • Antibody dilutions: 1:1000-1:2500

  • Paraffin-embedded tissues show membrane-specific staining

  • Signal intensity correlates with expression levels

• Immunofluorescence:

  • Antibody concentrations: 0.25-2 μg/mL

  • PFA-fixed, Triton X-100 permeabilized cells show characteristic membrane patterns

What considerations should be made when studying TMEM205 in patient-derived samples?

When investigating TMEM205 in clinical specimens, researchers should consider:

• Tissue selection and preparation:

  • TMEM205 expression has been successfully detected in snap-frozen human OCCC tissues

  • Both protein (Western blot) and RNA (qRT-PCR) can be analyzed from limited tissue quantities

  • Paraffin-embedded tissues are suitable for immunohistochemistry

• Expression variability:

  • Medium to high expression variability has been observed in OCCC tissues

  • This may correlate with treatment response

  • Consider obtaining paired samples (pre- and post-treatment) when possible

• Controls and standardization:

  • Include normal ovary epithelial cells as controls when studying ovarian cancers

  • Benign ovary tissues provide important comparison points

  • Quantify expression relative to standard housekeeping genes

• Correlation with clinical parameters:

  • Monitor treatment response

  • Track cisplatin resistance development

  • Potential biomarker value for predicting treatment outcomes

How can TMEM205 antibody be optimized for challenging applications like live-cell imaging?

For specialized applications like live-cell imaging, researchers should consider:

• Antibody fragment generation:

  • Fab fragments may provide better access to epitopes and reduced interference

  • Directly conjugated fluorescent Fab fragments minimize background

• Fluorophore selection:

  • Choose photostable fluorophores for long-term imaging

  • Consider using Alexa Fluor conjugates which are available for TMEM205 antibodies

  • Balance brightness against phototoxicity concerns

• Optimization strategies:

  • Titrate antibody concentrations (typically starting at 0.25-2 μg/mL)

  • Minimize exposure times

  • Consider using oxygen scavengers to reduce photobleaching

• Controls for live-cell studies:

  • Non-permeabilized cells should show surface-only labeling

  • Validate that antibody binding doesn't interfere with normal protein function

  • Include appropriate isotype controls (e.g., IgG2a or IgG2b)

What are the emerging areas of TMEM205 research beyond cisplatin resistance?

While cisplatin resistance has been the primary focus, several emerging research directions are promising:

• Role in normal physiology:

  • High expression in metabolically active organs (liver, pancreas, adrenal glands) suggests important physiological functions

  • Potential involvement in secretory pathways and hormone regulation

• Broader chemoresistance mechanisms:

  • Potential role in resistance to other platinum-based compounds

  • Possible involvement in multi-drug resistance phenotypes

• Diagnostic and prognostic applications:

  • Development as a biomarker for predicting treatment outcomes

  • Potential screening tool for patients likely to develop drug resistance

• Therapeutic targeting strategies:

  • Development of specific inhibitors targeting TMEM205

  • Exploration of combination therapies beyond oncolytic viruses

  • Investigation of nanomedicine approaches to overcome TMEM205-mediated drug efflux

How might single-cell analysis techniques advance our understanding of TMEM205 heterogeneity?

Single-cell technologies offer new opportunities to understand TMEM205 variation:

• Single-cell RNA sequencing:

  • Identify subpopulations with varying TMEM205 expression within tumors

  • Correlate with other resistance markers and pathways

  • Map temporal changes during treatment and resistance development

• Mass cytometry (CyTOF):

  • Simultaneously analyze TMEM205 expression alongside dozens of other markers

  • Characterize rare resistant cell populations

  • Track clonal evolution under treatment pressure

• Spatial transcriptomics:

  • Map TMEM205 expression patterns within tumor microenvironments

  • Correlate with distance from vasculature and drug penetration gradients

  • Identify niches that might promote resistance

• Integrative multi-omics approaches:

  • Combine proteomic, transcriptomic, and functional data

  • Build comprehensive models of TMEM205-associated resistance networks

  • Identify optimal intervention points for overcoming resistance