PTK2 (Ab-925) Antibody

What is PTK2 and what cellular processes does it regulate?

PTK2, also known as Focal Adhesion Kinase (FAK1), is a non-receptor protein-tyrosine kinase that plays critical roles in multiple cellular signaling pathways. It functions primarily in regulating cell motility, proliferation, and apoptosis processes. PTK2 is activated through tyrosine-phosphorylation, which can occur through several mechanisms: integrin clustering induced by cell adhesion, antibody cross-linking, G-protein coupled receptor (GPCR) activation by ligands such as bombesin or lysophosphatidic acid, or via LDL receptor occupancy . The protein has a reported length of 1052 amino acid residues with a molecular mass of approximately 119.2 kDa in its canonical form, though up to seven different isoforms have been identified . PTK2 is notably expressed in B and T-lymphocytes and has demonstrated involvement in angiogenesis and axon guidance . Recent research has also implicated PTK2 in neurodegenerative disease pathways, particularly through its role in the ubiquitin proteasome system (UPS) .

What are the key applications for PTK2 (Ab-925) Antibody?

PTK2 (Ab-925) Antibody has been validated for multiple experimental applications, making it versatile for different research contexts. Primary applications include:

The antibody has demonstrated reactivity with human, mouse, and rat samples, making it suitable for comparative studies across these species . Western Blot is particularly widely used with PTK2 antibodies, with over 2700 citations in scientific literature describing their research applications .

How should samples be prepared for optimal PTK2 detection?

Proper sample preparation is critical for successful PTK2 detection. For Western blot analysis, cell lysates should be prepared in a buffer containing phosphatase inhibitors to preserve the phosphorylation state of PTK2, particularly if studying its activated forms. Based on the provided Western blot images, HeLa cell extracts have been successfully used to detect PTK2 with the Ab-925 antibody .

For immunofluorescence studies, methanol fixation has been demonstrated to work effectively with this antibody, as shown in the product images with HeLa cells . For immunohistochemistry, the antibody performs well with paraffin-embedded tissues, as evidenced by the successful detection in human breast carcinoma tissue samples .

When troubleshooting, it's advisable to include both positive controls (tissues/cells known to express PTK2, such as HeLa cells) and negative controls (the antibody preincubated with blocking peptide) to confirm specificity, as demonstrated in the product validation images .

What are the critical storage and handling considerations for PTK2 (Ab-925) Antibody?

The PTK2 (Ab-925) Antibody is supplied at a concentration of 1.0mg/mL in phosphate buffered saline (without Mg²⁺ and Ca²⁺), pH 7.4, containing 150mM NaCl, 0.02% sodium azide, and 50% glycerol . This formulation is designed to maintain antibody stability during storage.

For optimal results:

• Store the antibody at -20°C

• Avoid repeated freeze-thaw cycles which can lead to antibody degradation

• When using the antibody, keep it on ice and return to storage promptly

• Working aliquots can be prepared to minimize freeze-thaw cycles

• The presence of sodium azide requires caution in handling and disposal due to its toxicity

How can researchers optimize detection of phosphorylated PTK2 forms?

Detecting phosphorylated forms of PTK2 requires specific considerations because post-translational modifications can significantly affect protein function and signaling. PTK2 undergoes tyrosine phosphorylation at several key residues, with Tyr397 being a critical autophosphorylation site that regulates its activation .

When studying phosphorylated PTK2:

• Sample preparation is critical: Use phosphatase inhibitors (sodium orthovanadate, sodium fluoride, β-glycerophosphate) in lysis buffers

• Consider cell stimulation protocols to increase phosphorylation: Integrin clustering via cell adhesion to fibronectin or stimulation with growth factors can enhance PTK2 phosphorylation

• Use phospho-specific antibodies in parallel with total PTK2 antibodies to calculate activation ratios

• When performing Western blots, consider longer blocking times (2-3 hours) to reduce background

• For immunoprecipitation studies, confirm that the antibody does not interfere with the phosphorylation sites of interest

While the PTK2 (Ab-925) Antibody targets a region around amino acids 923-927, researchers interested in specific phosphorylation sites should consider phospho-specific antibodies that target key regulatory sites such as Tyr397, Tyr407, or other relevant phosphorylation sites .

What role does PTK2/FAK play in neurodegenerative diseases and how can it be studied?

Recent research has identified PTK2/FAK as a significant player in neurodegenerative disease mechanisms, particularly through its interaction with the ubiquitin proteasome system (UPS) and its effects on TARDBP/TDP-43 proteinopathies . TARDBP proteinopathies are common features in neurodegenerative disorders including amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration (FTLD), and Alzheimer's disease (AD) .

Key findings and methodological approaches for studying PTK2 in neurodegeneration include:

• UPS Impairment Assessment: PTK2 has been identified as a suppressor of neurotoxicity induced by UPS impairment. Researchers can measure UPS function through ubiquitinated protein accumulation and proteasome activity assays in neuronal cells .

• Drosophila Models: PTK2 inhibition has been shown to reduce ubiquitin aggregates and attenuate TARDBP-induced cytotoxicity in Drosophila models, suggesting this as a valuable experimental system .

• SQSTM1/p62 Phosphorylation: The phosphorylation of SQSTM1/p62 at S403 (p-SQSTM1 [S403]) increases upon TARDBP overexpression and depends on PTK2 activation in neuronal cells. Studying this phosphorylation event provides insight into PTK2's role in autophagic degradation of poly-ubiquitinated proteins .

• Kinase Inhibitor Screening: This approach has successfully identified PTK2 as a regulator in neurodegenerative pathways, suggesting that kinase inhibitor panels can be valuable for identifying therapeutic targets .

For experimental design, researchers should consider:

• Using both cellular models and appropriate animal models (Drosophila has been validated)

• Implementing both gain-of-function (overexpression) and loss-of-function (inhibition) approaches

• Assessing multiple readouts: protein aggregation, cell viability, proteasome activity, and autophagy markers

How does the PTK2-TBK1-SQSTM1 axis function in protein degradation pathways?

The PTK2-TBK1-SQSTM1 axis represents a critical regulatory mechanism in protein degradation pathways, particularly in the context of neurodegenerative diseases. Research has revealed that:

• PTK2 activation influences the phosphorylation of SQSTM1/p62 at S403, which is a key regulatory step in the autophagic degradation of poly-ubiquitinated proteins .

• This phosphorylation is increased upon TARDBP overexpression and depends on PTK2 activation in neuronal cells .

• TBK1 (TANK binding kinase 1) functions as an intermediary kinase involved in the PTK2-mediated phosphorylation of SQSTM1 .

The following methodological approaches can be used to investigate this axis:

When designing experiments to study this axis, researchers should:

• Include controls for both phosphorylated and total protein levels

• Use multiple approaches to modulate PTK2 activity (genetic and pharmacological)

• Consider the temporal dynamics of the signaling cascade

• Assess both autophagic and proteasomal degradation pathways simultaneously

What experimental strategies can resolve contradictory findings when studying PTK2 function?

Researchers may encounter contradictory findings when studying PTK2 function due to its complex regulation and involvement in multiple signaling pathways. To resolve such contradictions:

• Consider Isoform Specificity: With up to seven different isoforms reported for PTK2 , experimental discrepancies may arise from isoform-specific effects. Use isoform-specific antibodies or primers, and clearly document which isoform is being studied.

• Account for Cell Type and Context Dependency: PTK2 function varies across cell types, particularly between neuronal and non-neuronal cells. The antibody has reactivity with human, mouse, and rat samples , allowing for cross-species validation of findings.

• Evaluate Phosphorylation State: PTK2 function is highly dependent on its phosphorylation state. Contradictory findings may result from differences in cellular activation status. Use phospho-specific antibodies alongside total PTK2 detection.

• Validate Antibody Specificity: As demonstrated in the product images, preincubation with blocking peptide should eliminate specific signals in Western blot, immunofluorescence, and immunohistochemistry . This control helps confirm that observed signals are specific to PTK2.

• Employ Multiple Detection Methods: Combine Western blot, immunofluorescence, and immunohistochemistry approaches as demonstrated in the product validation . Each method provides different information about protein expression, localization, and activation.

How can PTK2 (Ab-925) Antibody be incorporated into multiplex analysis systems?

For complex experimental designs requiring simultaneous detection of multiple proteins or modifications, PTK2 (Ab-925) Antibody can be incorporated into multiplex analysis systems:

• Multiplex Immunofluorescence: The antibody has been validated for immunofluorescence applications at dilutions of 1:100-1:200 . When designing multiplex panels:

  • Select additional antibodies raised in different host species to avoid cross-reactivity

  • Use fluorophores with minimal spectral overlap

  • Include appropriate controls for each antibody in the panel

  • Consider sequential staining protocols for challenging combinations

• Co-immunoprecipitation Studies: When studying PTK2 interactions with components of the PTK2-TBK1-SQSTM1 axis :

  • Optimize lysis conditions to preserve protein complexes

  • Use crosslinking approaches for transient interactions

  • Consider proximity ligation assays for in situ interaction detection

• Combined PTK2 and UPS Assessment: Given PTK2's role in UPS regulation , researchers can design experiments that simultaneously measure:

  • PTK2 activation status (phosphorylation)

  • UPS function (ubiquitinated protein accumulation)

  • Proteasome activity

  • SQSTM1/p62 phosphorylation

• Mass Spectrometry Integration: For comprehensive analysis of PTK2-dependent phosphorylation events:

  • Use the antibody for enrichment of PTK2-associated protein complexes

  • Combine with phospho-proteomics to identify novel targets

  • Validate mass spectrometry findings with targeted approaches using the antibody

What are the emerging research areas for PTK2 investigation?

Current research highlights the expanding role of PTK2 beyond its traditional functions in cell adhesion and migration. Particularly promising research directions include:

• Neurodegenerative Disease Mechanisms: The PTK2-TBK1-SQSTM1 axis plays a critical role in the pathogenesis of TARDBP-related neurodegeneration, suggesting PTK2 as a potential therapeutic target for conditions like ALS, FTLD, and AD .

• Protein Quality Control Systems: PTK2's involvement in regulating the ubiquitin proteasome system suggests broader roles in cellular protein quality control . This may extend to other protein degradation pathways and stress responses.

• Crosstalk Between Signaling Pathways: The interaction between PTK2 activation and TBK1-mediated phosphorylation of SQSTM1 exemplifies complex pathway crosstalk that warrants further investigation .

• Isoform-Specific Functions: With up to seven reported isoforms , research into isoform-specific functions and their differential expression across tissues and disease states represents an important area for future study.