FOXO4 (Ab-197) Antibody

What is FOXO4 (Ab-197) Antibody and what does it detect?

FOXO4 (Ab-197) Antibody is a rabbit polyclonal antibody raised against a specific peptide sequence around amino acids 195-199 (A-A-S-M-D) derived from human FOXO4 (also known as AFX or AFX1). This antibody detects endogenous levels of total FOXO4 protein, which functions as a transcription factor involved in the regulation of the insulin signaling pathway, cell cycle control, and response to oxidative stress. The antibody has demonstrated reactivity with human, mouse, and rat samples, making it versatile for comparative studies across these species.

What are the primary applications for FOXO4 (Ab-197) Antibody?

The FOXO4 (Ab-197) Antibody has been validated for multiple experimental applications including Western Blot (WB), Immunohistochemistry (IHC), and Enzyme-Linked Immunosorbent Assay (ELISA). For Western Blot applications, the recommended dilution range is 1:500-1:1000, while for Immunohistochemistry, the optimal dilution range is 1:50-1:200. The antibody has been successfully used in detecting FOXO4 protein in various tissue types including human breast cancer tissue and gastric cancer tissue, as demonstrated by scientific validation images.

What is the molecular function of FOXO4 protein in cellular processes?

FOXO4 functions as a transcription factor involved in multiple crucial cellular pathways. It regulates the insulin signaling pathway by binding to insulin-response elements (IREs) and can activate transcription of IGFBP1. Additionally, FOXO4 down-regulates expression of HIF1A and suppresses hypoxia-induced transcriptional activation of HIF1A-modulated genes. It plays important roles in metabolism, cell cycle regulation, apoptosis, and cellular homeostasis through its transcriptional activity. Upon activation, FOXO4 induces increased transcriptional activation of p21 and subsequent activation of cellular senescence. Research has also shown that FOXO4 controls cell responses to oxidative stress and anticancer therapy, making it a significant target in cancer research.

How should FOXO4 (Ab-197) Antibody be stored and handled to maintain optimal activity?

For optimal preservation of FOXO4 (Ab-197) Antibody activity, it should be stored at -20°C for long-term storage or at -80°C as recommended by some suppliers. For short-term use (within a few weeks), the antibody can be kept at 4°C. The antibody is typically supplied at a concentration of 1.0-2.6 mg/mL in phosphate buffered saline (without Mg²⁺ and Ca²⁺), pH 7.4, 150mM NaCl, 0.02% sodium azide, and 50% glycerol. It is crucial to avoid repeated freeze-thaw cycles as this can degrade the antibody and reduce its effectiveness. To minimize freeze-thaw cycles, it is recommended to aliquot the antibody into smaller volumes upon receipt before freezing.

What controls should be included when using FOXO4 (Ab-197) Antibody in immunohistochemistry (IHC)?

When performing immunohistochemistry with FOXO4 (Ab-197) Antibody, several controls should be included to ensure reliable and interpretable results. A positive control consisting of tissue known to express FOXO4 (such as human breast or gastric cancer tissue) should be included to verify antibody performance. A negative control where the primary antibody is omitted should be run to assess background staining. Additionally, a blocking peptide control, where the antibody is pre-incubated with the immunogenic peptide (the synthetic peptide derived from human FOXO4), should be included to confirm specificity. This is exemplified in the validation data showing paired images of FOXO4 antibody staining with and without synthetic peptide treatment, where the peptide-treated samples show significantly reduced staining, confirming the specificity of the antibody.

What is the recommended protocol for using FOXO4 (Ab-197) Antibody in Western Blot analysis?

For Western Blot analysis using FOXO4 (Ab-197) Antibody, the following protocol is recommended: After protein extraction and separation by SDS-PAGE, transfer proteins to a PVDF or nitrocellulose membrane. Block the membrane with 5% non-fat milk or BSA in TBST for 1 hour at room temperature. Incubate the membrane with FOXO4 (Ab-197) Antibody at a dilution of 1:500-1:1000 in blocking buffer overnight at 4°C. Wash the membrane 3-5 times with TBST, then incubate with an appropriate HRP-conjugated secondary antibody (such as goat anti-rabbit IgG H&L) at a dilution of 1:2000-1:5000 for 1 hour at room temperature. Wash again 3-5 times with TBST, then detect the signal using an enhanced chemiluminescence (ECL) system. The expected molecular weight of the FOXO4 protein is approximately 65 kDa. For optimal results, include positive and negative controls, and consider using a loading control antibody to normalize protein loading across lanes.

What are common causes of non-specific binding when using FOXO4 (Ab-197) Antibody, and how can they be mitigated?

Non-specific binding is a common challenge when working with antibodies like FOXO4 (Ab-197). Several factors can contribute to this issue: insufficient blocking, too high antibody concentration, cross-reactivity with related proteins, or sample preparation issues. To mitigate these problems, researchers should optimize blocking conditions (try different blocking agents like BSA, non-fat milk, or commercial blocking buffers), titrate the antibody concentration (start with the recommended dilution and adjust as needed), increase washing stringency (more washes or higher detergent concentration in wash buffer), and ensure proper sample preparation (complete lysis, proper denaturation for Western blot). For immunohistochemistry applications specifically, optimizing antigen retrieval methods and incubation times can significantly reduce background. The validation images showing comparative staining with and without peptide competition demonstrate the importance of confirming antibody specificity – when high background persists, peptide competition assays can help determine if the signal is specific to FOXO4.

How can researchers troubleshoot weak or no signal when using FOXO4 (Ab-197) Antibody?

When encountering weak or no signal with FOXO4 (Ab-197) Antibody, several approaches can resolve the issue. First, verify protein expression levels in your sample, as FOXO4 may be expressed at low levels in certain tissues or under certain conditions. For Western blot, increasing the amount of protein loaded (50-100 μg may be necessary), reducing antibody dilution (try 1:250 instead of 1:500), extending primary antibody incubation time (overnight at 4°C), or using a more sensitive detection system can improve signal detection. For IHC, optimize antigen retrieval methods (try different buffers and pH conditions), extend antibody incubation time, or use signal amplification systems like avidin-biotin complex or tyramide signal amplification. Additionally, verify antibody storage conditions, as improper storage or repeated freeze-thaw cycles can significantly reduce antibody activity. If using a secondary detection system, ensure the secondary antibody is compatible with the primary antibody species and isotype (for FOXO4 Ab-197, use anti-rabbit IgG secondary antibodies).

What are the considerations for cross-reactivity when using FOXO4 (Ab-197) Antibody across different species?

While FOXO4 (Ab-197) Antibody is reported to react with human, mouse, and rat samples, cross-reactivity considerations are important for experimental design and data interpretation. The antibody was raised against a peptide sequence (A-A-S-M-D) around amino acids 195-199 derived from human FOXO4. When using this antibody across species, researchers should consider sequence homology between species at the epitope region. Although the antibody has demonstrated reactivity in mouse and rat samples, validation may be necessary when working with these species, particularly for quantitative analyses. Species-specific positive controls should be included in experiments. Additionally, it's important to note that cross-reactivity might vary between applications (Western blot vs. IHC), as protein conformation and epitope accessibility can differ. When encountering unexpected results, sequence alignment analysis of the epitope region across species can provide insights. For critical experiments, validation using FOXO4 knockout or knockdown samples is recommended to confirm specificity across species.

How can FOXO4 (Ab-197) Antibody be used to study FOXO4's role in cancer progression and therapeutic response?

FOXO4 (Ab-197) Antibody offers valuable research applications for studying FOXO4's role in cancer progression and therapeutic response. Researchers can use this antibody in IHC to assess FOXO4 expression patterns across different cancer types and stages, correlating expression with clinical outcomes. The antibody has been validated on human breast and gastric cancer tissues, showing distinct nuclear and cytoplasmic staining patterns. By combining Western blot analysis with cell culture models treated with various anticancer compounds, researchers can monitor changes in FOXO4 expression, phosphorylation state, and subcellular localization in response to treatment. Since FOXO4 regulates genes involved in apoptosis and cell cycle control, the antibody can be used in chromatin immunoprecipitation (ChIP) assays to identify specific FOXO4 target genes activated or repressed during cancer progression or following therapeutic intervention. Additionally, the antibody can help investigate the relationship between FOXO4 and HIF1A expression, as FOXO4 has been shown to suppress hypoxia-induced transcriptional activation, which is relevant for understanding tumor microenvironment interactions and developing targeted therapies.

What approaches can be used to study the interplay between FOXO4 and insulin signaling pathways using this antibody?

To study the interplay between FOXO4 and insulin signaling pathways using FOXO4 (Ab-197) Antibody, researchers can implement several sophisticated approaches. Co-immunoprecipitation (Co-IP) experiments can identify protein-protein interactions between FOXO4 and other components of the insulin signaling pathway such as AKT, IRS proteins, or 14-3-3 proteins. Western blot analysis using phospho-specific antibodies alongside the FOXO4 antibody can help track insulin-induced FOXO4 phosphorylation status, which regulates its nuclear-cytoplasmic shuttling and transcriptional activity. Immunofluorescence microscopy with FOXO4 (Ab-197) Antibody can visualize the subcellular localization changes of FOXO4 in response to insulin stimulation or insulin resistance conditions. ChIP-seq experiments using this antibody can map genome-wide FOXO4 binding sites under various insulin signaling conditions, revealing how insulin regulates FOXO4's transcriptional program. For in vivo studies, immunohistochemistry in tissue samples from animal models of diabetes or insulin resistance can assess how pathological conditions affect FOXO4 expression and localization. Since FOXO4 binds to insulin-response elements (IREs) and activates transcription of IGFBP1, reporter gene assays combined with Western blot validation using this antibody can measure FOXO4 transcriptional activity in response to insulin signaling manipulations.

How can FOXO4 (Ab-197) Antibody be utilized in studying cellular senescence mechanisms?

FOXO4 (Ab-197) Antibody provides a powerful tool for investigating cellular senescence mechanisms, as FOXO4 has been implicated in senescence regulation through p21 activation. Researchers can utilize this antibody in time-course experiments to monitor FOXO4 expression and localization changes during senescence induction by various stressors (oxidative stress, DNA damage, oncogene activation). Combining FOXO4 immunostaining with senescence markers like SA-β-galactosidase can help establish correlations between FOXO4 activity and senescence progression at the single-cell level. ChIP assays using this antibody can identify senescence-specific FOXO4 target genes, particularly focusing on the p21 locus, to understand the transcriptional mechanisms involved. Co-immunoprecipitation experiments can reveal senescence-specific protein interaction partners of FOXO4, potentially identifying novel regulatory mechanisms. In intervention studies targeting senescence (senolytics, senomorphics), this antibody can track FOXO4 expression changes to understand the molecular mechanisms of these interventions. The antibody can also be used in comparative analyses of young versus senescent cells to map changes in FOXO4 post-translational modifications, providing insights into how aging affects FOXO4 regulation. Since FOXO4 expression is inhibited by microRNAs in various contexts, combining this antibody with microRNA profiling can identify senescence-associated miRNAs that target FOXO4, expanding our understanding of non-coding RNA regulation in senescence.

How should researchers interpret variations in FOXO4 subcellular localization in immunostaining experiments?

When interpreting variations in FOXO4 subcellular localization using FOXO4 (Ab-197) Antibody in immunostaining experiments, researchers should consider that FOXO4's function is tightly regulated by its nucleocytoplasmic shuttling. Predominantly nuclear localization generally indicates transcriptionally active FOXO4, suggesting low AKT activity and potentially active stress response or growth inhibition pathways. Conversely, cytoplasmic localization typically reflects inactive FOXO4, usually resulting from phosphorylation by AKT in response to insulin/growth factor signaling. Mixed nuclear and cytoplasmic staining may indicate transitional states or heterogeneous cell populations with varying signaling activity. Quantitative assessment should involve calculating nuclear/cytoplasmic ratio across multiple cells and experimental conditions, ideally using digital image analysis software for unbiased measurement. Co-staining with phospho-FOXO4 antibodies can provide additional insights into the activation state. When comparing FOXO4 localization between different tissues or treatment conditions, standardized imaging parameters and analysis methods are essential. The validation images showing FOXO4 staining in cancer tissues demonstrate how the antibody can reveal biologically relevant localization patterns that may correlate with pathological states.

What considerations are important when quantifying FOXO4 expression levels in Western blot experiments?

When quantifying FOXO4 expression levels in Western blot experiments using FOXO4 (Ab-197) Antibody, several methodological considerations are critical for obtaining reliable results. First, proper loading controls (such as β-actin, GAPDH, or total protein staining methods like Ponceau S) must be used to normalize FOXO4 signal intensity across samples. Post-translational modifications of FOXO4, particularly phosphorylation, can affect its electrophoretic mobility, potentially resulting in multiple bands or band shifts that need to be carefully interpreted. The expected molecular weight of FOXO4 is approximately 65 kDa, but researchers should be aware that post-translational modifications might cause deviations from this expected size. For accurate quantification, the linear dynamic range of both the antibody concentration and detection method should be established through preliminary titration experiments. Densitometric analysis should be performed using appropriate software that can distinguish specific signal from background, with consistent analysis parameters applied across all experimental conditions. When comparing FOXO4 levels between different experimental conditions, biological replicates (minimum of three) are essential for statistical validity. Additionally, researchers should consider that total FOXO4 protein levels may not reflect the active fraction, so complementary assays examining phosphorylation status or subcellular fractionation may provide more complete insights into FOXO4 activity.

What are the best practices for optimizing FOXO4 (Ab-197) Antibody concentration for novel sample types or applications?

When optimizing FOXO4 (Ab-197) Antibody concentration for novel sample types or applications, a systematic approach is recommended. Begin with a gradient titration experiment using the manufacturer's recommended dilution range as a starting point (1:500-1:1000 for Western blot; 1:50-1:200 for IHC). For Western blot optimization, prepare a dilution series (e.g., 1:250, 1:500, 1:1000, 1:2000) and apply to identical blots with the same protein samples. For IHC, create a similar dilution series (e.g., 1:25, 1:50, 1:100, 1:200) using serial sections of the same tissue. Evaluate results based on signal-to-noise ratio rather than absolute signal intensity—the optimal dilution provides clear specific staining with minimal background. For novel tissue types, include known positive control tissues (like human breast or gastric cancer tissues that have been validated) alongside your experimental samples to benchmark antibody performance. When developing new applications beyond WB, IHC, and ELISA, small-scale pilot experiments with varying antibody concentrations, incubation times, and buffer conditions are essential. Document all optimization steps methodically, as subtle protocol adjustments can significantly impact results. Remember that optimal antibody concentration may vary between batches, so recording the lot number during optimization is advisable.

How can FOXO4 (Ab-197) Antibody be integrated into multiplexed immunofluorescence protocols?

Integrating FOXO4 (Ab-197) Antibody into multiplexed immunofluorescence protocols requires careful planning to ensure compatibility with other antibodies while maintaining signal specificity. First, consider the host species—since FOXO4 (Ab-197) is a rabbit polyclonal antibody, other primary antibodies should ideally be from different host species (mouse, goat, chicken, etc.) to avoid cross-reactivity of secondary antibodies. For multiplex panels, select fluorophore-conjugated secondary antibodies with minimal spectral overlap. When direct conjugation is preferred, commercial antibody labeling kits can be used to directly label the FOXO4 antibody with a fluorophore of choice. Sequential staining protocols may be necessary when using multiple rabbit antibodies—this involves complete detection of the first primary antibody, followed by an elution or blocking step before applying the next primary antibody. Tyramide signal amplification (TSA) can be incorporated for weak signals, allowing the use of extremely dilute primary antibodies while maintaining detection sensitivity. For co-localization studies with other transcription factors or signaling proteins, nuclear counterstaining with DAPI is essential for proper subcellular localization assessment. Always include single-antibody controls to assess potential cross-talk between channels. When analyzing FOXO4 in relation to its regulatory partners or downstream targets, selecting markers relevant to insulin signaling, cellular stress response, or cell cycle regulation will provide the most biologically informative multiplex panels.

What approaches can researchers use to validate FOXO4 (Ab-197) Antibody specificity in their experimental system?

Comprehensive validation of FOXO4 (Ab-197) Antibody specificity is crucial for confident data interpretation. Multiple complementary approaches should be employed: Peptide competition assays, where the antibody is pre-incubated with excess immunizing peptide (the synthetic peptide derived from amino acids 195-199 of human FOXO4) before application to samples, should abolish specific signals. Genetic validation using FOXO4 knockout or knockdown models represents the gold standard—specific signals should be absent or significantly reduced in these samples compared to wild-type controls. Expression validation through correlation of protein detection with mRNA levels using qPCR or RNA-seq data can provide additional confidence in antibody specificity. Molecular weight verification in Western blot should show a predominant band at approximately 65 kDa, consistent with FOXO4's expected size. Multiple antibody validation using a second FOXO4 antibody targeting a different epitope should produce concordant results across applications. For advanced validation, mass spectrometry analysis of immunoprecipitated proteins can confirm that the antibody is capturing FOXO4 rather than cross-reactive proteins. Tissue expression pattern comparison with known FOXO4 expression profiles from public databases can provide additional validation context. Each validation method has strengths and limitations, so combining multiple approaches provides the most robust assessment of antibody specificity for your particular experimental system.