APLF (Ab-116) Antibody

What is APLF protein and what cellular functions does it perform?

APLF (Aprataxin and PNKP Like Factor) is a 57 kDa nuclear protein involved in DNA damage response pathways. It is also known by alternative names including APFL, C2orf13, and Xip1 . APLF functions primarily in the repair of DNA strand breaks by facilitating the recruitment of repair factors to damaged sites. The protein contains several functional domains that enable interactions with other DNA repair proteins and damaged DNA itself. APLF plays a critical role in maintaining genomic stability through its involvement in both non-homologous end joining (NHEJ) and base excision repair (BER) pathways, making it an important subject for cancer research and DNA damage response studies.

What are the key specifications of the APLF (Ab-116) Antibody?

The APLF (Ab-116) Antibody is a polyclonal antibody generated in rabbits using a synthetic non-phosphopeptide derived from human APLF around the phosphorylation site of serine 116 (R-N-S(p)-Q-V) . This antibody demonstrates reactivity against human and mouse APLF proteins . It is available in both unconjugated form and conjugated with various fluorescent labels including Biotin, AF350, AF405, AF488, AF555, AF594, AF647, AF680, and AF750, each with specific excitation and emission wavelengths tailored for different detection methods . The antibody is typically supplied at a concentration of 1 mg/ml in a buffer formulation of PBS (pH 7.4) containing 150 mM NaCl, 0.02% sodium azide, and 50% glycerol .

What applications is the APLF (Ab-116) Antibody validated for?

The APLF (Ab-116) Antibody has been validated for multiple research applications with specific recommended dilutions:

The antibody specifically detects endogenous levels of total APLF protein in experimental samples . When selecting this antibody for your research, it's important to verify that these applications align with your experimental design and that you adhere to the recommended dilution ranges for optimal results.

How does the APLF (Ab-116) Antibody differ from phospho-specific APLF antibodies?

The APLF (Ab-116) Antibody recognizes the region around serine 116 but is not phosphorylation-state specific, allowing detection of total APLF protein regardless of its phosphorylation status . In contrast, phospho-specific antibodies (such as anti-APLF (pSer116)) are designed to exclusively recognize APLF when phosphorylated at serine 116.

For comprehensive studies of APLF regulation, researchers should consider using both antibody types in parallel experiments. The phosphorylation-independent APLF (Ab-116) Antibody provides information about total protein expression levels, while phospho-specific antibodies reveal the activation state of the protein. This dual approach is particularly valuable when investigating how DNA damage induces post-translational modifications of APLF and the subsequent functional consequences.

What are the structural considerations when using antibodies against APLF in research?

When designing experiments with APLF (Ab-116) Antibody, it's important to understand antibody structure and how it relates to antigen recognition. The antibody's Fab region, specifically the complementarity determining regions (CDRs) formed by the variable domains of heavy and light chains (VH and VL), is responsible for antigen binding .

The polyclonal nature of this antibody means it contains a heterogeneous mixture of immunoglobulins that recognize multiple epitopes around serine 116 of APLF. This provides robust detection but may introduce variability between antibody lots. The antibody's elbow angle, which is the angle between the pseudo-two-fold axes relating the VH/VL and CH1/CL domain pairs, influences the accessibility to epitopes and may affect binding efficiency in different experimental contexts . Understanding these structural features can help researchers optimize experimental conditions for specific applications.

How can I validate the specificity of APLF (Ab-116) Antibody in my experimental system?

Validating antibody specificity is crucial for generating reliable experimental data. For APLF (Ab-116) Antibody, consider implementing the following validation strategy:

• Positive and negative controls: Include cell lines or tissues known to express high levels of APLF (positive control) and those with low or no expression (negative control).

• Knockdown/knockout verification: Use APLF siRNA or CRISPR-Cas9 gene editing to reduce APLF expression, which should correspondingly reduce or eliminate the signal from a specific antibody.

• Peptide competition assay: Pre-incubate the antibody with excess immunizing peptide (the synthetic peptide derived from human APLF around serine 116) before application to your samples. A specific antibody will show decreased or absent signal.

• Comparison with alternative APLF antibodies: Test multiple antibodies targeting different epitopes of APLF to confirm consistent protein detection patterns.

• Recombinant protein control: Use purified recombinant APLF protein as a standard for size verification in Western blots.

Proper validation ensures that the observed signals genuinely represent APLF and not non-specific binding or cross-reactivity with other proteins.

What is the optimal protocol for Western blotting with APLF (Ab-116) Antibody?

For optimal Western blot results with APLF (Ab-116) Antibody, follow this methodological approach:

Sample Preparation:

• Extract proteins using a lysis buffer containing protease inhibitors to prevent APLF degradation

• Determine protein concentration using Bradford or BCA assay

• Prepare samples in Laemmli buffer with 2-mercaptoethanol or DTT

• Heat samples at 95°C for 5 minutes to denature proteins

Electrophoresis and Transfer:

• Load 20-40 μg of protein per lane on an 8-10% SDS-PAGE gel (appropriate for the 57 kDa APLF protein)

• Run gel at 100-120V until adequate separation

• Transfer proteins to PVDF membrane (preferred over nitrocellulose for phospho-proteins) at 100V for 1 hour or 30V overnight at 4°C

Antibody Incubation and Detection:

• Block membrane with 5% BSA in TBST for 1 hour at room temperature

• Incubate with APLF (Ab-116) Antibody at 1:1000 dilution in blocking buffer overnight at 4°C

• Wash 3-4 times with TBST, 5 minutes each

• Incubate with HRP-conjugated secondary anti-rabbit antibody at 1:5000 dilution for 1 hour at room temperature

• Wash 3-4 times with TBST, 5 minutes each

• Develop using ECL substrate and capture images using appropriate detection system

Expected Results:
A specific band should be visible at approximately 57 kDa, representing the APLF protein . Depending on the cell type and experimental conditions, additional bands may represent post-translationally modified forms of APLF.

How should I optimize immunohistochemistry protocols using APLF (Ab-116) Antibody?

For immunohistochemistry applications with APLF (Ab-116) Antibody, consider the following protocol and optimization strategies:

Basic Protocol:

• Tissue Preparation:

  • Fix tissues in 10% neutral buffered formalin and embed in paraffin

  • Section tissues at 4-6 μm thickness and mount on positively charged slides

• Antigen Retrieval:

  • Deparaffinize and rehydrate sections

  • Perform heat-induced epitope retrieval using citrate buffer (pH 6.0) for 20 minutes

• Staining Procedure:

  • Block endogenous peroxidase with 3% H₂O₂ in methanol for 10 minutes

  • Block non-specific binding with 5% normal goat serum for 1 hour

  • Incubate with APLF (Ab-116) Antibody at 1:75 dilution overnight at 4°C

  • Apply HRP-conjugated secondary antibody for 1 hour at room temperature

  • Develop with DAB substrate and counterstain with hematoxylin

Optimization Considerations:

• Antibody Dilution: Begin with 1:75 dilution and adjust based on signal intensity

• Antigen Retrieval Method: Compare citrate buffer (pH 6.0) versus EDTA buffer (pH 9.0)

• Incubation Time: Test different primary antibody incubation times (1 hour at room temperature versus overnight at 4°C)

• Detection System: Compare standard HRP-polymer systems versus signal amplification methods like tyramide signal amplification

Since APLF is a nuclear protein involved in DNA repair, positive staining should appear predominantly in the nucleus of cells, particularly in tissues with high proliferation rates or under conditions of DNA damage.

How can I design experiments to study APLF phosphorylation at serine 116?

To investigate APLF phosphorylation at serine 116, design experiments that compare total APLF (using APLF (Ab-116) Antibody) with phosphorylated APLF (using phospho-specific antibodies):

• Treatment Conditions:

  • Expose cells to DNA damaging agents (e.g., ionizing radiation, etoposide, or H₂O₂)

  • Include time course experiments to capture phosphorylation dynamics

  • Test the effects of kinase inhibitors to identify the responsible kinase

• Analytical Methods:

  • Western Blotting: Run parallel blots with APLF (Ab-116) Antibody and phospho-specific anti-APLF (pSer116) antibody

  • Immunofluorescence: Co-stain with total and phospho-specific antibodies to visualize subcellular localization changes

  • Flow Cytometry: Quantify phosphorylation levels in response to treatments

  • Immunoprecipitation: Enrich for APLF protein followed by phospho-specific detection

• Controls:

  • Include phosphatase treatment of some samples to confirm phospho-specificity

  • Use APLF knockout or knockdown cells as negative controls

  • Consider using phosphomimetic (S116D) and phospho-dead (S116A) APLF mutants

This experimental approach will allow you to determine the conditions that induce serine 116 phosphorylation and the functional consequences of this post-translational modification on APLF's role in DNA damage response.

What are common issues when working with APLF (Ab-116) Antibody and how can they be resolved?

When working with APLF (Ab-116) Antibody, researchers may encounter several technical challenges. Here are common issues and their solutions:

For long-term storage stability, aliquot the antibody upon receipt and store at -20°C to avoid repeated freeze-thaw cycles that can degrade antibody performance .

How can I determine the appropriate controls for experiments using APLF (Ab-116) Antibody?

Proper controls are essential for interpreting experimental results with APLF (Ab-116) Antibody. Implement the following control strategy:

Positive Controls:

• Cell lines with confirmed APLF expression (e.g., HeLa, U2OS for human samples)

• Tissues with high DNA repair activity (e.g., testis, thymus, spleen)

• Recombinant APLF protein as a size standard in Western blots

Negative Controls:

• APLF knockout or knockdown cells/tissues

• Cell lines with naturally low APLF expression

• Primary antibody omission control to assess secondary antibody specificity

• Isotype control (rabbit IgG at the same concentration) to evaluate non-specific binding

Procedural Controls:

• Loading control antibodies (e.g., β-actin, GAPDH) to normalize protein loading

• Phosphatase-treated samples when comparing with phospho-specific antibodies

• DNA damage induction controls (e.g., γ-H2AX staining) when studying APLF in DNA repair contexts

Implementation of these controls will ensure experimental rigor and facilitate accurate interpretation of results obtained with APLF (Ab-116) Antibody.

What storage and handling practices maximize the shelf life and performance of APLF (Ab-116) Antibody?

To maintain optimal antibody performance and extend shelf life, follow these storage and handling guidelines:

• Initial Processing:

  • Upon receiving the antibody, prepare small working aliquots (10-20 μL) to minimize freeze-thaw cycles

  • Store in low-protein-binding tubes to prevent antibody loss through adsorption

• Storage Conditions:

  • Store all aliquots at -20°C as recommended by manufacturers

  • For conjugated versions, protect from light to prevent photobleaching of fluorophores

  • For short-term storage (less than one week), antibody can be kept at 4°C

• Handling Practices:

  • Allow antibody to equilibrate to room temperature before opening to prevent condensation

  • Centrifuge briefly before opening to collect liquid at the bottom of the tube

  • Use clean pipette tips for each handling to prevent contamination

  • Return to storage promptly after use

• Working Solution Preparation:

  • Prepare fresh working dilutions on the day of use

  • Use high-quality diluents (e.g., 1% BSA in PBS with 0.05% sodium azide)

  • Filter antibody solutions if particulates are visible

• Monitoring Performance:

  • Document lot numbers and performance characteristics

  • Periodically validate antibody performance with positive controls

  • Consider implementing a quality control system for antibody management

Proper storage and handling will ensure consistent experimental results and maximize the value of your APLF (Ab-116) Antibody investment.

How can APLF (Ab-116) Antibody be used to study protein-protein interactions in DNA damage response?

APLF (Ab-116) Antibody can be instrumental in investigating protein-protein interactions within DNA damage response pathways through several methodological approaches:

Co-Immunoprecipitation (Co-IP):

• Lyse cells under non-denaturing conditions to preserve protein-protein interactions

• Incubate lysate with APLF (Ab-116) Antibody to capture APLF protein complexes

• Isolate complexes using Protein A/G beads

• Analyze precipitated proteins by Western blot or mass spectrometry

This approach can identify proteins that interact with APLF in different contexts, such as before and after DNA damage induction. The polyclonal nature of APLF (Ab-116) Antibody makes it particularly suitable for Co-IP as it recognizes multiple epitopes, increasing the likelihood of capturing intact protein complexes.

Proximity Ligation Assay (PLA):

• Fix and permeabilize cells

• Incubate with APLF (Ab-116) Antibody and antibody against potential interacting protein

• Apply secondary antibodies with attached oligonucleotides

• Add connector oligonucleotides and ligase to form a circle when proteins are in proximity

• Amplify signal using polymerase and detect with fluorescent probes

PLA provides spatial information about protein interactions in situ, allowing visualization of where in the cell APLF interactions occur in response to DNA damage.

These methodologies can reveal novel interactions between APLF and other proteins involved in DNA repair pathways, contributing to our understanding of the molecular mechanisms underlying genome stability maintenance.

What considerations are important when using APLF (Ab-116) Antibody in fluorescence microscopy?

When employing APLF (Ab-116) Antibody for fluorescence microscopy studies, consider these technical and experimental factors:

Selection of Conjugated Versions:
The antibody is available with various fluorophore conjugations, each with specific excitation and emission profiles :

• AF488 (Ex: 493nm, Em: 519nm) is ideal for green channel imaging

• AF555 (Ex: 555nm, Em: 565nm) or AF594 (Ex: 591nm, Em: 614nm) work well for red channel

• AF647 (Ex: 651nm, Em: 667nm) is suitable for far-red detection

Select the appropriate conjugate based on your microscope's filter sets and other fluorophores in multi-color experiments.

Protocol Optimization:

• Fixation Method: Compare paraformaldehyde (4%) versus methanol fixation

• Permeabilization: Test different detergents (0.1% Triton X-100, 0.1% Saponin)

• Antigen Retrieval: Determine if heat-induced epitope retrieval improves detection

• Blocking: Use 5% normal serum from the same species as the secondary antibody

• Antibody Concentration: Start with 1:100 dilution and optimize based on signal-to-noise ratio

Co-localization Studies:
APLF functions in DNA damage response, so co-staining with markers such as γ-H2AX, 53BP1, or XRCC4 can reveal its recruitment to damage sites. When designing co-staining experiments, ensure fluorophores have minimal spectral overlap and select antibodies raised in different host species to prevent cross-reactivity.

Quantitative Analysis:
For quantifying APLF recruitment to DNA damage sites over time:

• Induce localized DNA damage using laser microirradiation

• Fix cells at different time points

• Immunostain with APLF (Ab-116) Antibody

• Capture images using consistent exposure settings

• Analyze fluorescence intensity at damage sites relative to nuclear background

Following these considerations will enable high-quality fluorescence microscopy data when studying APLF localization and dynamics.