SLC2A13 Antibody

What is SLC2A13 and what is its biological function?

SLC2A13 (solute carrier family 2, member 13) is a 648 amino acid multi-pass membrane protein belonging to the major facilitator superfamily and sugar transporter family. It functions primarily as a H+-myo-inositol cotransporter that can also transport related stereoisomers. The protein has 12 transmembrane domains, 3 N-glycosylation sites, and contains several motifs critical for glucose transport activity. SLC2A13 specifically transports myoinositol but not hexoses, with transport activity notably increasing as pH decreases from 7.0 to 5.0 . The protein contains an endoplasmic reticulum retention signal and dileucine internalization signal in the N-terminal region, suggesting regulated trafficking within cells .

What are the species homologies for SLC2A13?

Human SLC2A13 shares approximately 90% sequence identity with its rat homolog, indicating high evolutionary conservation . The antibodies available for research typically demonstrate cross-reactivity across multiple species. According to the literature, human (UniProt ID: Q96QE2), rat (UniProt ID: Q921A2), and mouse (UniProt ID: Q3UHK1) SLC2A13 proteins can be detected with appropriate antibodies . Some antibodies have also shown reactivity with pig samples . This high degree of conservation facilitates translational research across different model organisms.

What is the subcellular localization of SLC2A13?

SLC2A13 is a membrane-localized protein with multiple internalization signals, including an endoplasmic reticulum retention signal and a dileucine internalization signal in the N-terminal region, as well as a tyrosine-based internalization motif at the C-terminus . In cancer tissue studies, SLC2A13-expressing cells have been observed to form distinct clusters embedded within limited areas of tumor tissue, suggesting specialized microenvironmental localization . The protein undergoes glycosylation, which likely influences its trafficking and membrane insertion dynamics .

What are the recommended applications for SLC2A13 antibodies?

SLC2A13 antibodies are validated for multiple experimental applications. Western blot (WB) analysis is typically performed at dilutions ranging from 1:1000 to 1:8000, depending on the specific antibody and sample type . Immunohistochemistry applications generally use dilutions between 1:20 and 1:50 . Immunofluorescence techniques typically utilize the antibody at concentrations of 0.25-2 μg/mL . Sample-dependent optimization is recommended for each experimental system to achieve optimal results .

How should researchers interpret differences between calculated and observed molecular weights of SLC2A13?

The calculated molecular weight of SLC2A13 based on its amino acid sequence is approximately 70 kDa, but the observed molecular weight in Western blot applications typically ranges from 75-90 kDa . This discrepancy is attributable to post-translational modifications, particularly N-glycosylation at the three known glycosylation sites in the protein . When analyzing SLC2A13 expression patterns, researchers should account for potential variations in glycosylation states across different tissue types or experimental conditions, which may result in band shifts. Deglycosylation experiments using PNGase F or similar enzymes can help confirm band identity and assess glycosylation patterns in comparative studies.

What methodological approaches should be used to study SLC2A13 in the context of cancer stem cells?

To investigate SLC2A13 as a potential cancer stem cell marker, researchers should implement a multi-modal approach. Sphere-forming assays using primary tumor cells (particularly from oral squamous cell carcinoma) have been demonstrated as an effective method to enrich potential cancer stem cells for comparative analysis . Gene expression profiling between sphere-forming and non-sphere-forming cells can help confirm SLC2A13 upregulation. Confocal microscopy with appropriate antibody dilutions can be used to visualize the clustered distribution pattern characteristic of SLC2A13-positive cells within tumor tissues . Additionally, serum starvation in cell lines such as MCF7 has been shown to induce SLC2A13 expression, providing an in vitro model for mechanistic studies . Co-localization studies with established cancer stem cell markers can strengthen the association between SLC2A13 and stemness properties.

How can researchers optimize antibody performance for detecting SLC2A13 in different experimental systems?

Optimizing SLC2A13 antibody performance requires careful consideration of several factors. For Western blot applications, sample preparation should account for SLC2A13's membrane localization, with appropriate detergent-based lysis buffers (containing 1-2% Triton X-100 or similar non-ionic detergents) being recommended. For immunohistochemistry, antigen retrieval methods should be optimized, with citrate buffer (pH 6.0) typically yielding good results for membrane proteins. Since SLC2A13 has different expression levels across tissues (with higher expression in brain tissue), appropriate positive controls should be included . Antibody validation through knockdown/knockout experiments is strongly recommended to confirm specificity, particularly when studying tissues with potentially complex expression patterns such as tumor samples .

What are the implications of pH-dependent activity for SLC2A13 functional studies?

SLC2A13 transport activity is markedly increased when the extracellular pH decreases from 7.0 to 5.0, suggesting pH-dependent regulation of its function . When designing functional studies of SLC2A13, researchers should implement pH-controlled experimental conditions to properly evaluate transport activity. This pH sensitivity has particular relevance in cancer research, as the tumor microenvironment often exhibits acidic pH due to increased glycolysis and lactic acid production. Experimental designs should incorporate pH measurements and controlled pH buffers to accurately assess SLC2A13 contribution to myo-inositol transport in physiological versus pathological conditions. Transport assays using radiolabeled myo-inositol at varying pH conditions can provide insights into the functional significance of SLC2A13 upregulation in cancer stem cells.

What controls should be included when using SLC2A13 antibodies?

Rigorous experimental design with appropriate controls is essential for SLC2A13 antibody applications. Positive tissue controls should include brain tissue, which has demonstrated reliable SLC2A13 expression . Negative controls should include samples where the primary antibody is omitted or replaced with non-specific IgG of the same species and concentration. For cancer stem cell-related studies, researchers should include parallel staining of known stem cell markers for comparison. When evaluating specificity, peptide competition assays using the immunogen peptide can help confirm binding specificity. For Western blot applications, loading controls appropriate for membrane proteins should be selected, as traditional housekeeping genes may not accurately reflect loading for membrane-enriched fractions.

How should researchers approach conflicting SLC2A13 expression data across different experimental platforms?

When faced with discrepancies in SLC2A13 expression data between different experimental approaches (e.g., RNA sequencing versus protein detection), researchers should consider several factors. At the transcriptional level, evaluate primer specificity and potential alternative splicing that might affect detection. At the protein level, consider antibody epitope accessibility, protein conformation changes, and post-translational modifications that might mask epitopes. The membrane localization and trafficking signals in SLC2A13 may result in differential subcellular distribution under various conditions, affecting detection . Complementary approaches such as fluorescent protein tagging combined with live-cell imaging can help resolve localization discrepancies. Additionally, researchers should consider the dynamic regulation of SLC2A13 under different physiological conditions, such as pH changes or serum starvation, which have been shown to affect its expression and function .

What are the key considerations for storage and handling of SLC2A13 antibodies?

For optimal performance and longevity, SLC2A13 antibodies require careful handling and storage. Most commercial SLC2A13 antibodies are supplied in PBS buffer containing 50% glycerol and sometimes 0.02% sodium azide . These antibodies should be stored at -20°C, where they typically remain stable for one year after shipment . Aliquoting is generally unnecessary for -20°C storage, but may be considered for antibodies without stabilizing proteins like BSA. For 20 μl sized products containing 0.1% BSA as a stabilizer, minimize freeze-thaw cycles . Prior to use, antibodies should be gently mixed (not vortexed) after thawing to ensure homogeneity without damaging the protein structure. Working dilutions should be prepared fresh and ideally used within 24 hours for maximum efficacy.

How can SLC2A13 expression patterns be leveraged in cancer diagnosis and therapy?

The distinct expression pattern of SLC2A13 in cancer stem cells, particularly its clustered distribution within tumor tissues, presents opportunities for both diagnostic and therapeutic applications . For diagnostic purposes, researchers can develop multiparameter immunohistochemical panels that include SLC2A13 alongside established cancer stem cell markers to better identify tumor-initiating cell populations. This approach could improve prognostic classification, particularly in oral squamous cell carcinoma where SLC2A13 has been specifically implicated . Therapeutically, the membrane localization of SLC2A13 makes it a potential target for antibody-drug conjugates or immunotherapy approaches directed specifically at cancer stem cells. The protein's role in myo-inositol transport suggests potential metabolic targeting strategies, particularly considering the pH-dependent activity that might be exploited in the typically acidic tumor microenvironment .

What methodological advances might improve SLC2A13 functional characterization?

Emerging technologies offer new opportunities for detailed functional characterization of SLC2A13. CRISPR-Cas9 genome editing allows precise manipulation of SLC2A13 expression and the introduction of fluorescent tags at endogenous loci, enabling live-cell tracking of protein dynamics. Single-cell RNA sequencing combined with spatial transcriptomics can reveal the heterogeneity of SLC2A13 expression within tumors and correlate this with microenvironmental factors. Advanced imaging techniques such as super-resolution microscopy can better resolve the membrane distribution and potential clustering of SLC2A13 molecules. Metabolomic approaches focusing on myo-inositol and related compounds can link SLC2A13 expression to cellular metabolic states, particularly in the context of cancer stem cell metabolism. These methodological advances will help address current knowledge gaps regarding the functional significance of SLC2A13 upregulation in cancer stem cells.

How does SLC2A13 interact with the broader cancer stem cell signaling network?

Understanding how SLC2A13 integrates with established cancer stem cell pathways represents an important research direction. Given that SLC2A13 has been identified alongside other cancer stem cell markers in sphere-forming cells , researchers should investigate potential functional relationships with key stemness regulators like OCT4, NANOG, and SOX2. The myo-inositol transport function of SLC2A13 suggests connections to phosphoinositide signaling pathways, which are critical for cell proliferation and survival. Researchers should employ co-immunoprecipitation followed by mass spectrometry to identify potential protein interaction partners. Pathway analysis using pharmacological inhibitors or genetic perturbations can help position SLC2A13 within the hierarchical signaling network that maintains stemness properties. These investigations may reveal whether SLC2A13 is merely a marker of cancer stem cells or functionally contributes to stemness maintenance, potentially opening new therapeutic avenues.

What factors should researchers consider when quantifying SLC2A13 expression in tissue samples?

Accurate quantification of SLC2A13 expression in tissue samples requires careful consideration of several methodological aspects. The heterogeneous, cluster-like distribution of SLC2A13-positive cells in tumor tissues necessitates comprehensive sampling and analysis approaches . For immunohistochemical quantification, researchers should evaluate multiple fields and report both the percentage of positive cells and staining intensity. Digital pathology tools can help standardize analysis and reduce observer bias. When performing Western blot quantification, membrane fractionation protocols should be optimized to ensure consistent extraction efficiency across samples. Given the glycosylation-dependent variation in molecular weight (75-90 kDa) , researchers should quantify all relevant bands and report the total protein expression. Expression data should be normalized to appropriate membrane protein loading controls rather than traditional housekeeping genes, which may not accurately reflect membrane protein loading.

How should researchers approach SLC2A13 antibody validation for specialized applications?

Thorough antibody validation is essential for reliable SLC2A13 research, particularly in specialized applications such as cancer stem cell identification. For knockout validation, CRISPR-Cas9-mediated SLC2A13 knockout cell lines should be developed as definitive negative controls. RNA interference approaches using siRNA or shRNA can serve as additional validation tools, with the expectation of proportional signal reduction corresponding to knockdown efficiency. Epitope mapping using deletion constructs can help identify the specific binding region, which is valuable information when interpreting results from different antibodies targeting distinct epitopes. Multiple antibodies targeting different regions of SLC2A13 should be compared when possible to confirm expression patterns. For cancer stem cell research specifically, researchers should validate antibody performance in sphere-forming assays, comparing expression between sphere-forming and non-sphere-forming populations as an internal validation approach .