ATF2 (Ab-62 or 44) Antibody

What is ATF2 and what are its primary biological functions?

ATF2 (Activating Transcription Factor 2) is a member of the bZIP family of transcription factors that binds to the cAMP-responsive element (CRE) with the consensus sequence 5'-GTGACGT[AC][AG]-3'. This sequence is present in many viral and cellular promoters. ATF2 functions as a transcriptional activator regulating genes involved in anti-apoptosis, cell growth, and DNA damage response .

ATF2 is ubiquitously expressed but shows more abundant expression in the brain. It can form either homodimers or heterodimers with c-Jun, redirecting JUN to bind to CREs preferentially over the 12-O-tetradecanoylphorbol-13-acetate response elements (TREs) . Beyond transcriptional regulation, ATF2 exhibits histone acetyltransferase (HAT) activity that specifically acetylates histones H2B and H4 in vitro .

What are the recommended applications for ATF2 (Ab-62 or 44) Antibody?

The ATF2 (Ab-62 or 44) Antibody has been validated for multiple research applications:

The antibody detects endogenous levels of total ATF2 protein and has been shown to produce a specific band at approximately 60-80 kDa in Western blotting applications .

What is the immunogen used to generate this antibody and what species reactivity does it have?

The ATF2 (Ab-62 or 44) Antibody was generated using a peptide sequence around serine 60~64 or 42~46 (N-D-S-V-I) derived from human ATF2 . This immunogen was conjugated to KLH (keyhole limpet hemocyanin) carrier protein and used to immunize rabbits .

Confirmed species reactivity includes:

• Human

• Mouse

• Rat

Predicted reactivity (based on sequence homology) may extend to:

• Zebrafish

• Bovine

• Horse

• Sheep

• Rabbit

• Dog

• Chicken

• Xenopus

How should I optimize Western blot conditions for detecting ATF2?

For optimal Western blot results with ATF2 (Ab-62 or 44) Antibody:

• Sample preparation: Prepare cell or tissue lysates under reducing conditions. Use immunoblot buffer group 3 as demonstrated in validation studies .

• Protein loading: Load 5-30 μg of total protein per lane for cell line samples .

• Membrane selection: PVDF membranes have been successfully used for ATF2 detection .

• Blocking and antibody dilution:

  • Primary antibody: Use at 1:500-1:1000 dilution

  • Secondary antibody: HRP-conjugated Anti-Rabbit IgG (for rabbit host primary antibodies)

• Expected bands: ATF2 typically appears at approximately 60-80 kDa. The canonical form appears at ~74 kDa, while a ~54 kDa splice variant may also be detected .

• Controls: Include positive control samples such as HeLa human cervical epithelial carcinoma cell line, MCF-7 human breast cancer cell line, or NIH-3T3 mouse embryonic fibroblast cell line, which are known to express detectable levels of ATF2 .

• Validation: Consider running a peptide competition assay where the antibody is pre-incubated with the immunizing peptide, which should eliminate specific binding, as demonstrated in LOVO cell extracts .

How do phosphorylation states affect ATF2 detection and function?

ATF2 undergoes extensive phosphorylation at multiple sites, which significantly impacts both its detection by antibodies and its biological functions:

• Key phosphorylation sites:

  • Thr-69/Thr-71: Phosphorylated by p38 MAPK, JNK, and ERK in response to stress stimuli

  • Ser-44/Ser-62: Targeted by this specific antibody

  • Ser-490/Ser-498: ATM-mediated phosphorylation stimulates DNA damage response functions

  • Thr-73/Ser-121: Activates transcriptional activity

• Functional consequences of phosphorylation:

  • Enhanced transcriptional activity: Phosphorylation at Thr-69 and Thr-71 is required for heterodimerization with c-Jun

  • Increased HAT activity: Phosphorylation at Thr-69 or Thr-71 enhances histone acetyltransferase activity

  • Subcellular localization: Phosphorylation can affect nuclear vs. cytoplasmic distribution

  • DNA damage response: ATM-mediated phosphorylation at Ser-490 and Ser-498 is crucial for recruitment into ionizing radiation-induced foci (IRIF)

• Rapid phosphorylation kinetics: Studies show ATF2 phosphorylation can occur within 5 minutes of cellular stimulation, as demonstrated with N. meningitidis exposure .

• Detection considerations: For studying specific phosphorylation events, consider using phospho-specific antibodies alongside total ATF2 antibodies to differentiate between phosphorylated and non-phosphorylated forms .

What controls should be included when using ATF2 (Ab-62 or 44) Antibody?

When designing experiments with ATF2 (Ab-62 or 44) Antibody, include these essential controls:

• Positive controls:

  • Cell lines with known ATF2 expression: HeLa, MCF-7, NIH-3T3, LOVO, HEK-293T, K-562 cells

  • Tissue samples: Mouse brain tissue (has high endogenous ATF2 expression)

• Negative controls:

  • Peptide competition/blocking: Pre-incubate the antibody with the immunizing peptide to confirm specificity

  • Primary antibody omission: Replace primary antibody with buffer or non-immune IgG

  • Unstimulated cells: As baseline for phosphorylation studies

• Stimulus-specific controls (for phosphorylation studies):

  • Time course samples: ATF2 phosphorylation can occur rapidly (within 5-30 minutes) following stimulation

  • Known stimuli: LPS, UV radiation, or inflammatory cytokines can induce ATF2 phosphorylation

• Loading controls:

  • Western blot: COX IV or other housekeeping proteins

  • IHC/IF: Counter-staining for structural proteins (e.g., actin) can help normalize cellular context

How can I use this antibody to study ATF2 in cancer research models?

ATF2 has shown complex roles in cancer biology, functioning as either a tumor suppressor or oncogene depending on cellular context. When using ATF2 (Ab-62 or 44) Antibody in cancer research:

• ATF2 subcellular localization analysis:

  • In normal skin, ATF2 displays predominantly nuclear localization

  • In skin cancers (SCC and BCC), there is decreased nuclear and variable cytoplasmic ATF2 expression, suggesting that altered ATF2 localization may contribute to cancer development

  • Use immunofluorescence to analyze nuclear-to-cytoplasmic ratios in your cancer model

• Correlation with β-catenin expression:

  • Research has shown inverse correlation between ATF2 and β-catenin levels in skin cancers

  • Consider dual staining of ATF2 and β-catenin in tissue sections

• Tissue microarray (TMA) analysis:

  • TMAs have been successfully used to evaluate ATF2 expression patterns across multiple tumor samples

  • Quantify nuclear vs. cytoplasmic staining intensity using digital image analysis

• Experimental workflow for cancer cell lines:

  • Baseline expression: Determine ATF2 expression and phosphorylation status in your cancer cell line

  • Treatment response: Monitor changes in ATF2 phosphorylation after treatment with chemotherapeutic agents

  • Correlation with apoptotic markers: Analyze potential correlations between ATF2 status and apoptotic markers

How can I investigate the relationship between ATF2 phosphorylation and transcriptional activation?

To study the dynamic relationship between ATF2 phosphorylation and its transcriptional activity:

• Chromatin Immunoprecipitation (ChIP) coupled with quantitative PCR:

  • Use ATF2 (Ab-62 or 44) Antibody to immunoprecipitate ATF2-bound chromatin

  • Design primers for known ATF2 target genes containing cAMP-responsive elements (CRE) or AP-1 binding sites

  • Perform ChIP at different time points following stimulus to track recruitment dynamics

• Reporter gene assays:

  • Utilize promoter constructs containing wild-type or mutated ATF2 binding sites

  • The E-selectin promoter has been validated for ATF2 studies, with constructs like -166 (containing the ATF2 binding site) and -166M (with mutated ATF2 binding site)

  • Transfect cells with these constructs and measure reporter gene activity following stimulation

• Combined phosphorylation and transcriptional analysis:

  • Treat cells with stimuli known to activate ATF2 (UV, inflammatory cytokines, N. meningitidis)

  • Monitor ATF2 phosphorylation by Western blot using phospho-specific antibodies

  • In parallel, measure mRNA levels of ATF2 target genes using qRT-PCR

  • Correlate the kinetics of phosphorylation with transcriptional activation

• Phospho-mutant expression studies:

  • Express wild-type vs. phospho-mutant ATF2 (S44A, S62A) in ATF2-depleted cells

  • Assess the impact on target gene expression and cellular phenotypes

What are the best approaches to study ATF2 interactions with other transcription factors?

ATF2 functions in complex with other transcription factors, most notably c-Jun. To investigate these interactions:

• Co-immunoprecipitation (Co-IP):

  • Use ATF2 (Ab-62 or 44) Antibody to immunoprecipitate ATF2 complexes

  • Optimal conditions: 0.5-4.0 μg antibody for 1.0-3.0 mg of total protein lysate

  • Western blot for potential binding partners (c-Jun, Smad3/4, other bZIP family members)

  • Consider stimulus-dependent interactions (e.g., TGF-β induces ATF2-Smad3/4 interactions)

• Sequential ChIP (Re-ChIP):

  • First ChIP: Immunoprecipitate with ATF2 antibody

  • Second ChIP: Immunoprecipitate the eluted material with antibodies against potential partners

  • This approach identifies genomic loci where both factors co-occupy

• Proximity ligation assay (PLA):

  • Enables visualization of protein-protein interactions in situ

  • Use ATF2 antibody in combination with antibodies against potential interaction partners

  • Particularly useful for studying interactions that may be transient or context-dependent

• Functional validation of interactions:

  • Compare binding of ATF2 to CRE elements (TGACGTCA) when alone versus in partnership with c-Jun

  • Assess shifts from CRE to AP-1 element (TGACTCA) binding preference when heterodimerized

  • Use reporter constructs with different response elements to validate functional consequences

What are common issues in Western blot detection of ATF2 and how can they be resolved?

When using ATF2 (Ab-62 or 44) Antibody in Western blot applications, researchers may encounter these challenges:

• Multiple bands or unexpected molecular weight:

  • Expected band size: Primary band at approximately 74 kDa (canonical ATF2), with possible detection of a ~54 kDa splice variant

  • Resolution: Use positive control samples (HeLa, MCF-7, NIH-3T3) to establish correct band pattern

  • Phosphorylation can cause mobility shifts; compare with phosphatase-treated samples

• Weak or no signal:

  • Optimize primary antibody concentration (1:500-1:1000 dilution range)

  • Ensure correct buffer conditions: Immunoblot Buffer Group 3 has been validated

  • Increase protein loading (recommended: 5-30 μg total protein)

  • Extend primary antibody incubation (overnight at 4°C)

  • Enhance detection using signal amplification systems or increase exposure time

• High background:

  • Increase blocking time or blocking agent concentration

  • Add 0.1-0.5% Tween-20 to wash and antibody dilution buffers

  • Reduce primary and secondary antibody concentrations

  • Ensure freshness of reagents; avoid repeated freeze-thaw cycles

• Inconsistent results between experiments:

  • Standardize lysate preparation protocol

  • Use a manual defrost freezer and avoid repeated freeze-thaw cycles for antibody storage

  • Aliquot antibody upon receipt to minimize freeze-thaw cycles

How can I optimize immunohistochemistry protocols for ATF2 detection in tissue samples?

For successful immunohistochemical detection of ATF2 in tissue samples:

• Tissue fixation and processing:

  • Use 10% neutral buffered formalin for fixation

  • Avoid overfixation which can mask epitopes

  • Optimal section thickness: 4-6 μm

• Antigen retrieval methods:

  • Heat-induced epitope retrieval (HIER) in citrate buffer (pH 6.0) or EDTA buffer (pH 9.0)

  • Pressure cooking for 3-5 minutes or microwave heating for 10-20 minutes

• Blocking and antibody incubation:

  • Block with 5-10% normal serum from the same species as the secondary antibody

  • Antibody dilution: 1:50-1:200 for IHC applications

  • Incubation time: 1-2 hours at room temperature or overnight at 4°C

• Detection systems:

  • Polymer-based detection systems provide better signal-to-noise ratio than avidin-biotin methods

  • DAB (3,3'-Diaminobenzidine) produces a brown precipitate that contrasts well with hematoxylin counterstain

• Controls and validation:

  • Positive tissue control: Human breast carcinoma tissue has been validated

  • Negative controls: Primary antibody omission and peptide competition

  • Subcellular localization pattern: Normal skin shows predominantly nuclear ATF2 staining, while in skin cancers, nuclear staining is reduced

• Scoring and interpretation:

  • Evaluate both nuclear and cytoplasmic staining separately

  • Consider using a scoring system based on staining intensity and percentage of positive cells

  • Compare with β-catenin expression patterns as they may show inverse correlation

What considerations are important when studying ATF2 phosphorylation dynamics?

ATF2 phosphorylation is a dynamic process that requires careful experimental design:

• Time course considerations:

  • ATF2 phosphorylation can occur rapidly, within 5-30 minutes of stimulation

  • Include early time points (5, 15, 30 minutes) and later time points (1, 2, 4 hours)

  • Phosphorylation may be transient; dense time point sampling is recommended

• Stimulus selection:

  • Cellular stress inducers: UV radiation, inflammatory cytokines

  • Bacterial components: Fixed N. meningitidis H44/76, LPS (though responses differ)

  • Growth factors: TGF-β (activates ATF2 via TAK1-p38 pathway)

• Phosphorylation site specificity:

  • Different stimuli may induce phosphorylation at different sites

  • Thr-69/71: Commonly phosphorylated by p38, JNK, ERK

  • Ser-44/62: Sites detected by this antibody

  • Ser-490/498: ATM-dependent phosphorylation sites involved in DNA damage response

• Detection methods comparison:

  • Western blot: Quantitative assessment of phosphorylation levels

  • Immunofluorescence: Visualizes subcellular localization of phosphorylated ATF2

  • Phospho-specific antibodies are essential for site-specific analyses

• Quantification approach:

  • For Western blots: Normalize phospho-ATF2 signal to total ATF2

  • For immunofluorescence: Measure nuclear-to-cytoplasmic ratio of phospho-ATF2

  • Present data as fold change relative to unstimulated controls

How should I interpret differences in ATF2 subcellular localization?

ATF2 can localize to different cellular compartments, with significant functional implications:

• Normal pattern vs. pathological changes:

  • Normal tissue (e.g., skin): Predominantly nuclear localization

  • Cancer tissues (SCC, BCC): Decreased nuclear and variable cytoplasmic localization

  • Stress conditions: May induce nuclear-to-cytoplasmic translocation

• Functional implications of localization:

  • Nuclear ATF2: Transcriptional activity, DNA damage response

  • Cytoplasmic ATF2: Interaction with mitochondrial proteins (HK1, VDAC1), potential pro-apoptotic function

  • Mitochondrial outer membrane: Perturbs membrane potential, may promote cell death

• Quantification methods:

  • Nuclear/cytoplasmic intensity ratio using digital image analysis

  • Subcellular fractionation followed by Western blot quantification

  • Statistical comparison between normal and diseased tissues using appropriate tests (e.g., Student's t-test, p-value < 0.05 considered significant)

• Correlation with clinical parameters:

  • Changes in ATF2 localization may correlate with tumor grade, invasion, or prognosis

  • Analyze in context of other molecular markers (e.g., β-catenin)

How can ATF2 (Ab-62 or 44) Antibody be used in multi-parametric analyses?

For comprehensive understanding of ATF2 biology, combine multiple analytical approaches:

• Multi-color immunofluorescence:

  • Co-stain for ATF2 with interacting partners (c-Jun) or related signaling molecules (p38, JNK)

  • Include markers for subcellular compartments (nuclear envelope, mitochondria, cytoskeleton)

  • Use spectral unmixing for accurate separation of fluorophores

• Combined phosphorylation and localization analysis:

  • Use ATF2 (Ab-62 or 44) Antibody with phospho-specific antibodies

  • Analyze whether particular phosphorylation states correlate with specific subcellular localization

  • Implement time-course studies to establish causality between phosphorylation and localization changes

• ChIP-seq combined with transcriptome analysis:

  • Use ATF2 (Ab-62 or 44) Antibody for ChIP-seq to identify genome-wide binding sites

  • Correlate binding with gene expression changes (RNA-seq) following stimulation or in disease models

  • Integrate with public datasets on histone modifications to analyze correlation with ATF2's HAT activity

• High-content imaging:

  • Automated microscopy with multiple fluorescence channels

  • Quantify nuclear/cytoplasmic ratios across large cell populations

  • Correlate with cell cycle stages or apoptotic markers

• Data integration and visualization:

  • Use principal component analysis or t-SNE to visualize multi-parametric data

  • Network analysis to place ATF2 in context of related signaling pathways

  • Correlation matrices to identify relationships between ATF2 status and cellular phenotypes

What are emerging applications for ATF2 antibodies in single-cell analysis techniques?

As single-cell technologies advance, ATF2 (Ab-62 or 44) Antibody can be applied in several cutting-edge approaches:

• Single-cell Western blotting:

  • Analyze ATF2 expression and phosphorylation states in individual cells

  • Reveals cell-to-cell heterogeneity masked in bulk analyses

  • Optimize antibody dilution (start with 1:500) and detection methods for low protein amounts

• Mass cytometry (CyTOF):

  • Metal-tagged antibodies enable simultaneous detection of >40 proteins

  • ATF2 antibody can be conjugated with rare earth metals

  • Combine with markers for cell type, cell cycle, and signaling pathways

  • Allows correlation of ATF2 status with cellular phenotypes at single-cell resolution

• Spatial transcriptomics with protein detection:

  • Combine ATF2 immunodetection with spatial transcriptomics

  • Correlate ATF2 protein localization with mRNA expression patterns of target genes

  • Provides spatial context to ATF2 function in tissue sections

• Live-cell imaging with tagged nanobodies:

  • Develop nanobodies based on ATF2 (Ab-62 or 44) epitope specificity

  • Conjugate with fluorescent proteins for live-cell tracking

  • Monitor real-time changes in ATF2 localization and concentration in response to stimuli

• CODEX multiplexed imaging:

  • Cyclic immunofluorescence allowing detection of >40 proteins in tissue sections

  • Include ATF2 antibody in antibody panel

  • Analyze spatial relationships between ATF2 and multiple markers in tissue context