The TARDBP Antibody, FITC conjugated combines a high-affinity monoclonal or polyclonal antibody with fluorescein isothiocyanate (FITC), a fluorescent dye emitting at 519 nm (excitation: 495 nm) . This conjugation enables visualization of TDP-43 protein localization via fluorescence microscopy or flow cytometry. The antibody targets epitopes within the middle region (e.g., amino acids 200–414) or N-terminal region of TDP-43, ensuring detection of both wild-type and post-translationally modified forms (e.g., phosphorylated, ubiquitinated) .
Antigen Retrieval: Mandatory for paraffin-embedded tissues to resolve nuclear localization defects in ALS/FTLD samples .
Cross-Reactivity: Tested in human, mouse, rat, and zebrafish models .
FITC Conjugation: Enhances signal-to-noise ratio in fluorescence assays .
Purification Methods: Affinity chromatography (e.g., Protein A/G) .
Stability: Lyophilized or liquid formulations require light protection to prevent FITC degradation .
ALS/FTLD Pathology: FITC-conjugated antibodies detect cytoplasmic TDP-43 aggregates, a hallmark of neurodegeneration .
Cancer Research: TDP-43 overexpression in triple-negative breast cancer (TNBC) suggests its role in oncogenesis .
G335D Mutation: Enhances TDP-43 aggregation and amyloid formation, linked to familial ALS .
Q343R Mutation: Disrupts aggregation propensity, highlighting structural determinants of TDP-43 toxicity .
TARDBP (TAR DNA-binding protein 43) is an RNA-binding protein crucial for various stages of RNA biogenesis and processing. Its two RNA recognition motifs (RRM1 and RRM2) preferentially bind GU-rich repeats, primarily found within long introns and the 3' untranslated regions (UTRs) of mRNAs. This binding regulates the splicing of numerous coding and non-coding RNAs, including those encoding proteins vital for neuronal survival and those implicated in neurodegenerative diseases. TARDBP maintains mitochondrial homeostasis by modulating mitochondrial transcript processing, influences mRNA stability by recruiting the CNOT7/CAF1 deadenylase complex to mRNA 3' UTRs (resulting in poly(A) tail shortening), and contributes to cell survival by associating with stalled ribosomes in stress granules (SGs) in response to oxidative stress. It also participates in skeletal muscle development and regeneration through cytoplasmic myo-granule formation and binding to mRNAs encoding sarcomeric proteins. Furthermore, TARDBP regulates circadian clock periodicity by stabilizing CRY1 and CRY2 proteins in an FBXL3-dependent manner and negatively regulates CDK6 expression. Finally, it modulates the expression of HDAC6, ATG7, and VCP in a PPIA/CYPA-dependent manner.
TARDBP (TAR DNA-binding protein 43) functions as an RNA-binding protein with diverse roles in cellular processes. It has emerged as a significant molecule in both neurodegenerative disorders and cancer biology. In neurodegenerative contexts, TARDBP mislocalization and aggregation form the pathological hallmark of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) . In oncology, particularly hepatocellular carcinoma (HCC), TARDBP has transitioned from being primarily associated with neurodegeneration to being recognized for its contributions to critical cellular processes including proliferation, apoptosis, and metastasis . This protein's involvement in both disease categories makes it a compelling target for diverse research applications.
FITC-conjugated TARDBP antibodies are versatile tools applicable across multiple experimental approaches:
Immunofluorescence microscopy - For subcellular localization studies, particularly when examining TARDBP mislocalization from nucleus to cytoplasm
Flow cytometry - For quantitative assessment of TARDBP expression in cell populations
Live cell imaging - For monitoring dynamic TARDBP localization changes
Tissue section analysis - For examining TARDBP distribution in pathological specimens
These techniques are particularly valuable when examining TARDBP's abnormal cytoplasmic accumulation, as demonstrated in studies of both neurodegenerative disorders and cancer models .
Research indicates that TARDBP expression patterns vary significantly across tissue types and disease states:
This tissue-specific expression profile should guide experimental design and interpretation when using TARDBP antibodies .
Optimization for TARDBP immunofluorescence requires careful attention to several parameters:
Fixation method - Paraformaldehyde (4%) generally preserves TARDBP epitopes while maintaining cellular architecture
Permeabilization - Critical for accessing intracellular TARDBP; Triton X-100 (0.1-0.5%) is typically effective
Blocking conditions - BSA (3-5%) with normal serum matching the secondary antibody host
Antibody concentration - Typically 1-10 μg/mL, requiring titration for optimal signal-to-noise ratio
Antigen retrieval - May be necessary for formalin-fixed tissue sections
Nuclear counterstaining - DAPI commonly used to distinguish nuclear vs. cytoplasmic TARDBP localization
When examining pathological samples, it's crucial to optimize these parameters specifically for detecting cytoplasmic TARDBP accumulation, as this antibody has demonstrated specificity for the cytoplasmic fraction of TDP43 in previous studies .
Verifying antibody specificity for TARDBP requires multiple complementary approaches:
Positive controls - Cell lines or tissues known to express TARDBP (e.g., neuronal cells, HCC cell lines)
Negative controls - TARDBP knockout cells or tissues
Peptide competition assays - Pre-incubating antibody with purified TARDBP peptide should abolish specific staining
Multiple antibody validation - Comparing staining patterns using antibodies targeting different TARDBP epitopes
siRNA knockdown - Reduced signal following TARDBP knockdown confirms specificity
Western blot correlation - Confirming molecular weight matches expected TARDBP size (~43 kDa)
When using domain-specific antibodies like those targeting the RRM1 domain of TARDBP, additional validation may be needed to ensure epitope accessibility in different experimental conditions .
Given TARDBP's complex subcellular distribution patterns, particularly in pathological states, comprehensive controls are essential:
Normal tissue controls - Demonstrating typical nuclear TARDBP localization
Subcellular fractionation validation - Confirming antibody specificity for cytoplasmic vs. nuclear fractions
Co-localization markers - Nuclear (e.g., DAPI) and cytoplasmic (e.g., β-tubulin) markers to confirm compartmentalization
Disease-relevant positive controls - ALS/FTLD tissue for neurodegenerative studies; HCC tissue for cancer studies
Treatment response controls - Samples treated with compounds known to alter TARDBP localization
Previous research has established that certain antibodies, like the E6 monoclonal antibody, specifically recognize the cytoplasmic fraction of TARDBP, making proper controls crucial for accurate interpretation .
TARDBP has been implicated in immune regulation within the tumor microenvironment. Advanced applications for studying this relationship include:
Multiplex immunofluorescence - Co-staining TARDBP with immune markers (CD274/PD-L1, CTLA4) to analyze correlation at the cellular level
Flow cytometry - Quantifying TARDBP expression in isolated immune cell populations
Sorted cell analysis - Examining TARDBP expression in specific immune cell subsets isolated from tumor tissue
Spatial transcriptomics integration - Correlating TARDBP protein localization with immune gene expression patterns
Research has shown significant positive correlations between TARDBP expression and immune checkpoint molecules CD274 and CTLA4, suggesting important regulatory connections . This correlation opens avenues for investigating combined therapeutic strategies targeting both TARDBP and checkpoint pathways to enhance anti-tumor immunity.
Distinguishing pathological from normal TARDBP distribution requires sophisticated methodological approaches:
High-resolution confocal microscopy - Enabling precise subcellular localization analysis
Super-resolution techniques - STORM or STED microscopy for nanoscale distribution patterns
Live cell imaging - Tracking TARDBP dynamics in response to cellular stressors
Quantitative image analysis - Nuclear:cytoplasmic ratio measurements across experimental conditions
Solubility fractionation - Biochemical separation of soluble vs. aggregated TARDBP species
Studies have demonstrated that cytoplasmic mislocalization and aggregation of TARDBP are characteristic of both neurodegenerative disorders and certain cancers, making these approaches valuable for pathological investigations .
Investigating TARDBP degradation pathways is critical for understanding disease mechanisms and developing therapeutic strategies. Advanced methodological approaches include:
Proteasome inhibition studies - Using MG132 to block proteasomal degradation while monitoring TARDBP levels
Lysosomal inhibition - Applying compounds like bafilomycin A1 to evaluate lysosomal contribution
TRIM21-dependent mechanisms - Investigating the E3 ubiquitin ligase TRIM21's role in antibody-mediated TARDBP clearance
Pulse-chase experiments - Measuring TARDBP half-life under various experimental conditions
Ubiquitination analysis - Immunoprecipitation followed by ubiquitin detection
Research has identified both the TRIM21/proteasome and lysosomal degradation pathways as potential mechanisms for antibody-mediated TARDBP degradation, suggesting therapeutic potential for targeting pathological TARDBP accumulation .
Recent research positions TARDBP as a promising cancer biomarker, particularly for hepatocellular carcinoma. Emerging applications include:
Tissue microarray analysis - High-throughput evaluation of TARDBP expression across large patient cohorts
Liquid biopsy development - Detecting TARDBP in circulating tumor cells or exosomes
Multiplex biomarker panels - Combining TARDBP with other prognostic markers
Pathological staging correlation - Relating TARDBP expression patterns to tumor grade/stage
Treatment response prediction - Evaluating TARDBP as a predictive biomarker for therapy selection
Studies indicate that TARDBP expression correlates with adverse patient outcomes in HCC, with ROC analysis demonstrating strong predictive value for HCC incidence . This positions TARDBP antibodies as valuable tools for translational cancer research.
The correlation between TARDBP expression and tumor mutational burden (TMB) represents a significant research direction requiring sophisticated methodological approaches:
Integrated multi-omics analysis - Correlating TARDBP protein levels with genomic mutation profiles
Single-cell approaches - Examining TARDBP expression and mutation signatures at single-cell resolution
CRISPR-mediated TARDBP modulation - Evaluating effects on genomic stability and mutation rates
DNA damage response analysis - Investigating TARDBP's potential role in DNA repair mechanisms
Longitudinal mutation accumulation studies - Tracking mutation development in relation to TARDBP expression levels
Research has demonstrated positive correlations between TARDBP expression and TMB across several cancer types, suggesting potential involvement in genomic instability mechanisms underlying cancer progression .
The positive correlation between TARDBP and immune checkpoint molecules (CD274/PD-L1 and CTLA4) presents intriguing opportunities for mechanistic investigation:
Co-immunoprecipitation studies - Examining physical interactions between TARDBP and checkpoint proteins
Transcriptional regulation analysis - Investigating TARDBP's potential role in regulating checkpoint gene expression
ChIP-seq/RIP-seq approaches - Mapping TARDBP binding to regulatory regions or transcripts of checkpoint genes
Immune checkpoint blockade models - Evaluating TARDBP expression changes following checkpoint inhibition
Patient-derived xenograft models - Testing combined targeting of TARDBP and checkpoint pathways
Research has shown that immunotherapeutic interventions targeting CD274 and CTLA-4 checkpoints have demonstrated promising efficacy across various solid tumors, with ongoing clinical trials evaluating their potential in HCC . Understanding the mechanistic connections with TARDBP could inform novel combination therapeutic approaches.
Several technical challenges may arise when using FITC-conjugated TARDBP antibodies:
Photobleaching - FITC is relatively susceptible to photobleaching; use anti-fade mounting media and minimize exposure
Autofluorescence - Particularly problematic in tissues with high lipofuscin content; utilize autofluorescence quenching protocols
pH sensitivity - FITC fluorescence is optimal at alkaline pH; maintain appropriate buffer conditions
Spectrum overlap - Plan multiplex experiments carefully to avoid bleed-through with other fluorophores
Fixation artifacts - Certain fixatives may alter TARDBP epitope accessibility or create background
Cytoplasmic vs. nuclear discrimination - Low-quality images may fail to distinguish these critical compartments
Methodological refinements include using longer-wavelength conjugates for tissues with high autofluorescence, optimizing fixation protocols specifically for TARDBP epitope preservation, and employing spectral unmixing for multiplex applications.
Detection of pathological cytoplasmic TARDBP inclusions presents specific methodological challenges:
Epitope masking - Protein aggregation may conceal antibody binding sites; optimize antigen retrieval methods
Inclusion heterogeneity - Different types of TARDBP inclusions may require specific detection approaches
Sensitivity limitations - Early/subtle cytoplasmic mislocalization may be difficult to detect; enhance signal amplification
Background interference - Non-specific cytoplasmic staining can obscure true inclusions; rigorous blocking protocols
Quantification challenges - Establish objective criteria for inclusion identification and counting
Research with antibodies targeting specific domains of TARDBP, like the RRM1 domain, has demonstrated efficacy in recognizing cytoplasmic species in both cellular systems and mouse models . These approaches can be adapted for FITC-conjugated antibodies with appropriate methodological refinements.
Optimal experimental design for TARDBP studies in disease contexts requires careful planning:
Time course analysis - TARDBP mislocalization may be dynamic; include multiple time points
Appropriate disease models - Select models that recapitulate human TARDBP pathology (e.g., ALS/FTLD mice for neurodegeneration, HCC xenografts for cancer)
Cell type specificity - TARDBP pathology may affect specific cell populations; employ cell-type markers
Quantitative metrics - Establish objective parameters (nuclear:cytoplasmic ratio, inclusion counts)
Statistical power - Ensure sufficient sample sizes for detecting potentially subtle changes
Studies have demonstrated that intrathecal injections of antibodies against the RRM1 domain of TARDBP resulted in large neuron penetration and mitigation of cytoplasmic TARDBP mislocalization in mouse models . Similar methodological considerations should guide experiments with FITC-conjugated TARDBP antibodies.
The research landscape for TARDBP continues to evolve, suggesting several innovative applications:
Intravital imaging - Real-time visualization of TARDBP dynamics in living organisms
High-content screening - Large-scale evaluation of compounds affecting TARDBP localization
Correlative light-electron microscopy - Linking fluorescence patterns to ultrastructural features
Microfluidic single-cell analysis - High-throughput quantification of TARDBP distribution patterns
Combinatorial therapeutic development - Monitoring TARDBP as a biomarker for response to emerging treatments
The continued refinement of both antibody technology and imaging methodologies promises to enhance our understanding of TARDBP's complex roles in both neurodegenerative disorders and cancer .
TARDBP research spans disease boundaries, suggesting integrated therapeutic approaches:
Antibody-based therapeutics - Building on findings that full-length antibodies against TARDBP can mitigate proteinopathy
Small molecule modulators - Targeting TARDBP mislocalization or aggregation with membrane-permeable compounds
Combined checkpoint/TARDBP targeting - Exploring synergies based on correlations between TARDBP and immune checkpoints
TRIM21/proteasome pathway enhancement - Boosting endogenous clearance mechanisms for cytoplasmic TARDBP
RNA-based interventions - Targeting TARDBP-regulated RNA processing events