tlk2 Antibody

What is TLK2 and why is it important for cellular function?

TLK2 is a nuclear serine/threonine kinase that plays crucial roles in chromatin assembly regulation, intracellular signaling cascades, protein phosphorylation, cell cycle regulation, and DNA damage response. TLK2 displays maximal activity during the S phase of the cell cycle and appears to be regulated by cell-cycle-dependent phosphorylation. Inhibition of DNA replication causes rapid loss of TLK2 activity, indicating its function is tightly linked to ongoing DNA replication. TLK2 is cell-cycle regulated and can be inactivated by phosphorylation at Ser-750, potentially by CHK1. It heterodimerizes with TLK1 and is widely expressed across tissues including fetal placenta, liver, kidney, pancreas, heart, and skeletal muscle .

How do I select the appropriate TLK2 antibody for my research application?

Selection depends on your specific experimental needs:

• For Western blotting: Polyclonal antibodies like Proteintech 13979-1-AP show reactivity with human, mouse, and rat samples at dilutions of 1:500-1:2000 .

• For immunohistochemistry: TLK2 antibodies with validated IHC applications are available with recommended dilutions of 1:50-1:500 .

• For immunofluorescence: Consider antibodies with documented nuclear localization patterns since TLK2 is predominantly nuclear .

• For co-immunoprecipitation studies: Monoclonal antibodies such as Santa Cruz E-12 (sc-393506) are effective for protein-protein interaction studies .

Additionally, consider species reactivity. For example, Thermo Fisher A301-257A antibody is predicted to react with mouse TLK2 based on 100% sequence identity .

What is the molecular weight of TLK2 and how does this affect antibody detection?

TLK2 has a calculated molecular weight of 88 kDa (772 amino acids), but is typically observed at approximately 85 kDa in Western blot applications . This slight discrepancy may be due to post-translational modifications or protein folding. When selecting antibodies, verify the expected molecular weight in your experimental system, especially if using tagged recombinant constructs which may alter the apparent molecular weight. Additionally, be aware that phosphorylation states of TLK2 can affect migration patterns in SDS-PAGE, particularly during different cell cycle phases when TLK2 activity fluctuates .

What are the optimal conditions for detecting TLK2 in Western blot applications?

For optimal TLK2 detection in Western blotting:

• Sample preparation: Nuclear fractionation may improve detection since TLK2 is predominantly nuclear.

• Protein loading: 20-40 μg of total protein is typically sufficient.

• Gel percentage: 8-10% SDS-PAGE gels provide good resolution for the 85 kDa TLK2 protein.

• Transfer conditions: Semi-dry or wet transfer at 100V for 60-90 minutes.

• Blocking: 5% non-fat milk or BSA in TBST for 1 hour at room temperature.

• Primary antibody: Dilutions of 1:500-1:2000 for polyclonal antibodies like Proteintech 13979-1-AP, incubated overnight at 4°C .

• Detection systems: Both HRP-conjugated secondary antibodies and fluorescent detection systems are compatible.

Positive controls include MCF-7 and HeLa cell lysates, which have been validated for TLK2 expression .

How can I optimize immunofluorescence protocols for TLK2 subcellular localization studies?

For optimal immunofluorescence detection of TLK2:

• Fixation: 4% paraformaldehyde for 15 minutes at room temperature preserves nuclear architecture.

• Permeabilization: 0.2% Triton X-100 for 10 minutes enables antibody access to nuclear TLK2.

• Blocking: 3-5% BSA or normal serum for 1 hour.

• Primary antibody: Use dilutions between 1:50-1:500 as recommended for antibodies like Proteintech 13979-1-AP .

• Incubation time: Overnight at 4°C for optimal signal-to-noise ratio.

• Secondary antibody selection: Compatible fluorescent conjugates (Alexa Fluor, FITC, or PE).

• Nuclear counterstain: DAPI or Hoechst to confirm nuclear localization.

HeLa cells serve as excellent positive controls for TLK2 immunofluorescence studies, with expected nuclear staining patterns .

What controls should be included when validating TLK2 antibody specificity?

Comprehensive validation requires multiple controls:

• Positive tissue/cell controls: MCF-7 and HeLa cells show consistent TLK2 expression .

• Negative controls: Primary antibody omission and isotype controls.

• Peptide competition assays: Pre-incubation with immunizing peptide should abolish specific signals.

• siRNA/shRNA knockdown: TLK2 depletion should diminish antibody signal. Studies have demonstrated successful TLK2 knockdown validation using inducible shRNA systems in MCF7 and MDAMB361 cells .

• Knockout verification: When available, TLK2 knockout samples provide definitive specificity confirmation.

• Recombinant protein controls: Using purified TLK2 protein (95% purity by SDS-PAGE) as a positive control .

• Rescue experiments: Re-expression of TLK2 in knockdown cells should restore antibody signal, as demonstrated in studies using MCF7 cells with inducible expression of TLK2 ORF containing silent mutations at shRNA targeting sites .

How can TLK2 antibodies be employed for studying protein-protein interactions in chromatin regulation pathways?

TLK2 antibodies can be strategically applied to dissect protein-protein interactions using these approaches:

• Co-immunoprecipitation (Co-IP): Antibodies like Santa Cruz E-12 (sc-393506) or agarose-conjugated variants can pull down TLK2 complexes. Research has shown TLK2 interactions with TLK1, ASF1 (a key substrate), and LC8 .

• Proximity ligation assays (PLA): Combining TLK2 antibodies with antibodies against putative interaction partners to visualize protein proximity in situ.

• BioID approaches: Studies have employed spatial proteomics (BioID) techniques to investigate the proximity interaction landscape of TLK2, revealing novel interaction networks .

• Domain mapping: Using antibodies to different TLK2 domains to understand interaction interfaces. Deletion of the CC1 domain strongly impairs interaction with both TLK1 and LC8 but doesn't influence ASF1 binding .

• Chromatin immunoprecipitation (ChIP): To study TLK2 association with specific genomic loci.

A systematic approach combining these techniques provides comprehensive insights into TLK2's roles in chromatin regulation networks.

What are the challenges in detecting phosphorylated forms of TLK2, and how can they be overcome?

Detecting phosphorylated TLK2 presents several challenges:

• Temporal dynamics: TLK2 phosphorylation varies throughout the cell cycle, with maximal activity during S-phase .

• Multiple phosphorylation sites: TLK2 contains numerous phosphorylation sites, including regulatory Ser-750 .

• Low abundance: Phosphorylated forms may represent a small fraction of total TLK2.

Methodological approaches to overcome these challenges:

• Phosphatase inhibitors: Include sodium orthovanadate, sodium fluoride, and β-glycerophosphate in lysis buffers.

• Cell synchronization: Synchronize cells in S-phase when TLK2 activity peaks.

• Phospho-specific antibodies: Although limited, phospho-specific antibodies for key regulatory sites can be developed.

• Phos-tag SDS-PAGE: Enhances separation of phosphorylated protein forms.

• Mass spectrometry: For comprehensive phosphorylation site mapping.

• Lambda phosphatase treatment: Use as a control to confirm phosphorylation-dependent mobility shifts.

• Recombinant expression systems: Generate samples with or without autophosphorylations for comparative analysis .

How can TLK2 antibodies be used to investigate its role in DNA damage response and replication stress?

TLK2 antibodies can be utilized in several experimental approaches to study its DNA damage response functions:

• Immunofluorescence co-localization: Investigate TLK2 localization relative to DNA damage markers (γH2AX, 53BP1) following damage induction. Optimized protocols use 1:50-1:200 antibody dilutions .

• Cell cycle analysis: Combine with flow cytometry to examine TLK2 levels across cell cycle phases before and after DNA damage.

• Chromatin fractionation: TLK2 antibodies can track protein recruitment to chromatin following DNA damage.

• Kinase activity assays: Immunoprecipitate TLK2 after damage to assess activity changes toward substrates.

• DNA replication inhibition studies: TLK2 activity rapidly decreases following replication inhibition, which can be monitored using activity-specific assays .

• CHK1-dependent regulation: Investigate the relationship between CHK1-mediated phosphorylation of TLK2 at Ser-750 and its inactivation following DNA damage .

For meaningful results, appropriate damage inducers (UV, ionizing radiation, hydroxyurea, or etoposide) should be used with proper time-course experiments.

How are TLK2 antibodies being used to investigate its role in breast cancer progression?

TLK2 antibodies have revealed important insights into breast cancer pathophysiology:

• Amplification analysis: Immunohistochemistry studies using TLK2 antibodies have confirmed protein overexpression in breast cancer tissues with gene amplification .

• Mechanistic investigations: TLK2 has been identified as a lead target amplified in ER+ breast cancers through systematic 'ConSig-Amp' analysis of genomic data .

• Functional validation: Antibodies have been used to validate TLK2 knockdown efficiency in breast cancer cell lines like MCF7 and MDAMB361, demonstrating decreased colony-forming ability and inhibition of anchorage-independent growth .

• Migration and invasion studies: Antibodies have demonstrated that TLK2 overexpression in T47D cells strongly enhances cell migration and invasion capabilities in a dose-dependent manner .

• Signaling pathway analysis: Western blot analysis using TLK2 antibodies has revealed signaling changes following TLK2 overexpression in breast cancer cells .

What research approaches can be used to study TLK2's role in hepatocellular carcinoma using available antibodies?

Recent research has implicated TLK2 in hepatocellular carcinoma progression through Wnt/β-catenin pathway activation . TLK2 antibodies enable several investigative approaches:

• Expression analysis: IHC studies comparing TLK2 expression between normal liver and hepatocellular carcinoma tissues can identify correlations with clinical outcomes.

• Mechanistic studies: Co-immunoprecipitation experiments using TLK2 antibodies can identify interactions with β-catenin pathway components.

• Functional studies: Using antibodies to validate knockdown efficiency in genetic manipulation experiments investigating proliferation, migration, and invasion.

• Pathway analysis: Combining TLK2 antibodies with antibodies against β-catenin pathway components (β-catenin, TCF/LEF, GSK3β) for co-localization studies.

• Therapeutic target validation: TLK2 antibodies can measure changes in expression or activity following experimental therapeutics.

Research has demonstrated that TLK2 promotes hepatocellular carcinoma proliferation specifically through β-catenin activation, representing a novel finding that expands understanding of TLK2's oncogenic functions .

How can TLK2 antibodies contribute to understanding its role in neurodevelopmental disorders?

TLK2 mutations are associated with Mental Retardation Autosomal Dominant 57 (MRD57, OMIM 618050), characterized by intellectual disability, behavioral abnormalities, facial dysmorphisms, microcephaly, epilepsy, and skeletal anomalies . TLK2 antibodies facilitate research in this area through:

• Expression analysis: Examining TLK2 expression patterns in neuronal tissues and cell types.

• Variant functional studies: Comparing wild-type and mutant TLK2 expression, localization, and interactions. For example, studies have investigated the effects of p.(Asp551Gly) and p.(Ser617Leu) variants .

• Interaction landscapes: BioID spatial proteomics combined with TLK2 antibodies have revealed TLK2's proximity interaction landscape in neuronal contexts .

• DNA damage response: Single-cell gel electrophoresis combined with TLK2 antibodies can evaluate the impact of disease-associated variants on DNA repair functions .

• Expression quantification: Real-time PCR assays can be validated using TLK2 antibodies to confirm protein-level changes correspond to transcript alterations .

What are the considerations when using TLK2 antibodies for multiplexing in imaging or flow cytometry applications?

Multiplexing with TLK2 antibodies requires careful planning:

• Antibody compatibility: When selecting antibody combinations, consider:

  • Host species: Avoid cross-reactivity by selecting antibodies from different species

  • Isotype differences: For monoclonal antibodies, use different isotypes (e.g., IgG1, IgG2b)

  • Format compatibility: Consider direct conjugates like TLK2 Antibody (E-12) FITC, PE, or Alexa Fluor variants

• Optimization strategies:

  • Sequential staining: For challenging combinations, apply primary antibodies sequentially

  • Signal amplification: Consider tyramide signal amplification for low-abundance targets

  • Controls: Include fluorescence minus one (FMO) controls for accurate gating

  • Spectral compensation: Essential for flow cytometry with multiple fluorophores

• Application-specific considerations:

  • For imaging: TLK2's nuclear localization must be distinguished from cytoplasmic markers

  • For flow cytometry: Cell permeabilization is critical for detecting nuclear TLK2

How can recombinant TLK2 proteins be used to enhance antibody validation and functional studies?

Recombinant TLK2 proteins serve multiple purposes in research:

• Antibody validation:

  • Western blot positive controls: Recombinant proteins with >95% purity provide definitive size standards

  • Peptide competition assays: For confirming antibody specificity

  • Standard curves: For quantitative applications

• Functional studies:

  • Kinase activity assays: Active recombinant TLK2 enables in vitro substrate identification

  • Structure-function analysis: Domain-specific constructs help map functional regions

  • Protein-protein interaction studies: As baits in pull-down experiments

• Available formats and applications:

  • Full-length vs. truncated: Different constructs are available (e.g., Leu397-Asn772 fragment)

  • Tagged variants: GST, His, Strep, and other tags for different purification and detection needs

  • Expression systems: Insect cells, HEK-293, and cell-free protein synthesis options with varying advantages

What analytical techniques can be combined with TLK2 antibodies to study its cell cycle-dependent regulation?

Multiple analytical approaches can be integrated with TLK2 antibodies:

• Flow cytometry:

  • Cell cycle synchronization followed by TLK2 antibody staining

  • Dual staining with cell cycle markers (e.g., Ki67, PCNA, BrdU)

  • Quantification of TLK2 levels across G1, S, G2, and M phases

• Live-cell imaging:

  • Combining fixed-cell TLK2 antibody validation with live-cell fluorescent protein fusions

  • Tracking TLK2 dynamics through cell division

• ChIP-seq applications:

  • Cell cycle-staged chromatin immunoprecipitation to map TLK2 genomic associations

  • Integration with replication timing data

• Phosphoproteomics:

  • Cell cycle-specific phosphorylation mapping

  • Identification of TLK2 substrates across cell cycle phases

  • Validation of Ser-750 phosphorylation by CHK1 and its impact on TLK2 activity

• DNA replication studies:

  • Combining DNA fiber analysis with TLK2 immunofluorescence

  • Measuring TLK2 activity following replication stress

Understanding TLK2's cell cycle-dependent regulation is crucial, as it displays maximal activity during S phase and is rapidly inactivated upon DNA replication inhibition .

How might TLK2 antibodies contribute to development of targeted cancer therapies?

TLK2 antibodies are instrumental in advancing therapeutic development through:

• Target validation: TLK2 has emerged as a promising therapeutic target, particularly in cancers where it's amplified, such as ER+ breast cancers identified through systematic 'ConSig-Amp' analysis .

• Biomarker development:

  • Patient stratification: TLK2 antibodies can identify tumors with TLK2 overexpression

  • Response prediction: Monitoring TLK2 expression/activity during treatment

  • Resistance mechanisms: Investigating TLK2-related bypass pathways

• Drug discovery support:

  • High-throughput screening: Antibody-based assays for TLK2 inhibitor discovery

  • Target engagement: Confirming compound binding to TLK2 in cells

  • Pharmacodynamic markers: Measuring effects on TLK2 activity or downstream pathways

• Combination therapy rationales:

  • DNA damage response inhibitors: TLK2's role in DNA damage response suggests potential synergies

  • Wnt/β-catenin pathway inhibitors: Based on TLK2's role in hepatocellular carcinoma

What are the most promising approaches for studying TLK2's role in chromatin dynamics using current antibody technologies?

Advanced chromatin research with TLK2 antibodies includes:

• ChIP-seq and CUT&RUN:

  • High-resolution mapping of TLK2 chromatin occupancy

  • Integration with histone modification data

  • Cell cycle-specific binding patterns

• Proximity-based approaches:

  • BioID and APEX2: For identifying proximal chromatin proteins

  • RIME (Rapid Immunoprecipitation Mass spectrometry of Endogenous proteins): Combining TLK2 ChIP with mass spectrometry

• Live-cell chromatin dynamics:

  • Combining fixed-cell antibody validation with live-cell imaging

  • FRAP (Fluorescence Recovery After Photobleaching) to study TLK2 chromatin binding kinetics

• Multi-omics integration:

  • Correlating TLK2 binding with nucleosome positioning

  • Integrating with replication timing data

  • Relationship to transcriptional activity

• ASF1 regulation:

  • Mechanistic studies of how TLK2 regulates its key substrate ASF1, which has been demonstrated to co-precipitate with TLK2 in pull-down experiments

How can contradictory findings about TLK2 function be reconciled through improved antibody-based methodologies?

Resolving contradictions requires robust methodological approaches:

• Specificity verification:

  • Cross-validation with multiple antibodies recognizing different epitopes

  • Genetic controls: siRNA/shRNA knockdown or CRISPR knockout validation

  • Rescue experiments: Re-expression of TLK2 in knockout backgrounds

• Context-dependent functions:

  • Cell type specificity: Compare antibody reactivity across different cell types

  • Tissue-specific expression: Systematic IHC analysis across tissues

  • Species differences: Compare human vs. mouse TLK2 localization and function

• Isoform-specific detection:

  • Antibodies targeting specific TLK2 variants

  • Combined RNA-seq and protein analysis to correlate transcript and protein isoforms

• Quantitative approaches:

  • Absolute quantification: Using purified standards

  • Stoichiometry determination: Of TLK2 complexes with interacting partners

  • Single-cell analysis: To address population heterogeneity

• Functional readouts:

  • Kinase activity assays: To distinguish between presence and activity

  • Substrate phosphorylation: As proxies for TLK2 function