Phospho-AR (Y363) Antibody

What is Phospho-AR (Y363) Antibody and what does it specifically detect?

The Phospho-AR (Y363) antibody specifically recognizes the androgen receptor when phosphorylated at tyrosine 363 . This antibody is typically generated by immunizing rabbits with a synthesized phosphopeptide derived from human Androgen Receptor around the phosphorylation site of tyrosine 363 (D-Y-YP-N-F) . The androgen receptor is a nuclear receptor that functions as a transcription factor involved in male phenotype development and reproductive physiology . It binds active testosterone (T) and dihydrotestosterone (DHT) as part of its regulatory function . The specificity of this antibody for the phosphorylated form makes it valuable for studying the phosphorylation state of AR in various experimental conditions.

What are the recommended applications and dilutions for Phospho-AR (Y363) Antibody?

The Phospho-AR (Y363) antibody has been validated for several applications with specific recommended dilutions:

Optimal dilutions should be determined by each researcher for their specific experimental conditions as noted in multiple sources . The antibody has not been widely validated for other techniques such as immunohistochemistry or immunofluorescence based on the available search results.

What are the optimal storage conditions for Phospho-AR (Y363) Antibody?

For long-term storage, the antibody should be stored at -20°C or -80°C . For short-term storage and frequent use, 4°C is suitable for up to one month . The antibody is typically supplied as a liquid in PBS containing 50% glycerol, 0.5% BSA, and 0.02% sodium azide . It is critical to avoid repeated freeze-thaw cycles as this can damage the antibody and reduce its effectiveness . For optimal preservation, it is recommended to aliquot the antibody upon receipt before freezing .

What species reactivity does the Phospho-AR (Y363) Antibody exhibit?

The antibody has confirmed reactivity against the phosphorylated AR from multiple species:

This cross-species reactivity suggests conservation of the phosphorylation site and surrounding amino acid sequence across these mammalian species, making the antibody valuable for comparative studies.

How is the specificity of Phospho-AR (Y363) Antibody validated?

The specificity of the antibody is typically validated through several complementary approaches:

• Western blot analysis showing detection of the phosphorylated form but not the non-phosphorylated form of AR

• Peptide competition assays where the antigenic phosphopeptide blocks antibody binding

• Comparison of antibody reactivity in samples treated with or without phosphatase

• Use of Y363F mutant AR as a negative control, similar to the approach used for other phospho-tyrosine sites

• Validation across multiple cell lines and tissues expressing AR

Boster Bio reports validating all their antibodies "on WB, IHC, ICC, Immunofluorescence, and ELISA with known positive control and negative samples to ensure specificity and high affinity" .

What is the functional significance of AR phosphorylation at Y363?

While the direct functional consequence of AR Y363 phosphorylation is not explicitly detailed in the search results, insights can be drawn from studies of similar tyrosine phosphorylation events. In the case of Cbl-b Y363 phosphorylation, this modification disrupts intramolecular interactions and exposes binding surfaces for other proteins .

By analogy, AR Y363 phosphorylation may:

• Alter AR conformation and protein-protein interactions

• Modify DNA binding affinity or specificity

• Influence transcriptional activity through recruitment of cofactors

• Affect AR stability or cellular localization

• Modulate response to ligands such as DHT and testosterone

Researchers studying AR Y363 phosphorylation should consider these potential mechanisms when designing experiments to elucidate its specific function in AR signaling.

How does Y363 phosphorylation compare to other documented phosphorylation sites on the androgen receptor?

The androgen receptor contains multiple phosphorylation sites with diverse functions. From search result , we know that AR has several well-characterized phosphorylation sites including S81, S213, S791, and T850.

The specific comparison of Y363 phosphorylation with these sites warrants further investigation to determine its relative importance in AR signaling networks.

What experimental techniques can be optimized for studying AR Y363 phosphorylation dynamics?

To effectively study the dynamics of AR Y363 phosphorylation, researchers can employ several techniques:

• Time-course experiments: Monitor Y363 phosphorylation following hormone stimulation or kinase activation

• Kinase inhibitor studies: Use specific inhibitors to identify the kinase(s) responsible for Y363 phosphorylation

• Phosphatase treatment experiments: Demonstrate specificity of the antibody and study dephosphorylation dynamics

• Mutagenesis studies: Create Y363F mutants to assess the functional consequences of preventing phosphorylation

• Mass spectrometry: Confirm phosphorylation and identify other post-translational modifications that may interact with Y363 phosphorylation

• Proximity ligation assays: Detect interactions between phosphorylated AR and potential binding partners in situ

Based on approaches used for other phosphorylation sites , these methods could reveal the kinetics, regulation, and functional significance of Y363 phosphorylation.

How can structural biology approaches help understand the impact of Y363 phosphorylation?

Based on the structural analysis methods described for Cbl-b Y363 phosphorylation , several techniques can elucidate the structural changes induced by AR Y363 phosphorylation:

• NMR spectroscopy: Can reveal detailed structural changes following phosphorylation. In the case of Cbl-b, "phosphorylation of Y363, located in the helix-linker region between the tyrosine kinase binding and the RING domains, disrupts the interdomain interaction to expose the E2 binding surface of the RING domain" .

• Small-angle X-ray scattering (SAXS): Provides information about the solution structure and can detect large conformational changes. For Cbl-b, SAXS analysis showed that "the unphosphorylated N-terminal region forms a compact structure by an intramolecular interaction" .

• Chemical shift perturbation methods: Used to study protein-protein interactions and can identify surfaces involved in binding other proteins following phosphorylation.

• Fluorescence polarization spectroscopy: Can measure binding affinities between AR and its interaction partners, as was done for Cbl-b where "phosphorylation of Y363 increases the affinity toward UbcH5B by about 20-fold" .

These approaches could reveal how Y363 phosphorylation alters AR structure and function at the molecular level.

What are potential kinases responsible for AR Y363 phosphorylation?

While the search results don't directly identify kinases responsible for AR Y363 phosphorylation, insights can be drawn from related studies:

• Tyrosine phosphorylation is typically mediated by tyrosine kinases, with Src family kinases being prominent candidates

• In studies of Cbl-b Y363 phosphorylation, "the phosphorylation reaction was carried out using fusion protein between c-Src kinase domain and Zap70 (SDGYTPEP) fragment to enhance phosphorylation efficiency"

• In context of receptor signaling, receptor tyrosine kinases or cytoplasmic tyrosine kinases could potentially phosphorylate AR Y363

• Growth factor signaling pathways that activate tyrosine kinases might regulate AR Y363 phosphorylation

Experimental approaches to identify the responsible kinase(s) could include:

• In vitro kinase assays with purified kinases

• Kinase inhibitor screens

• siRNA/shRNA-mediated knockdown of candidate kinases

• Phospho-proteomic analysis following activation of specific signaling pathways

What are the key considerations for optimal Western blot detection of phosphorylated AR Y363?

For optimal Western blot detection of phosphorylated AR Y363, researchers should consider the following methodological details:

• Sample preparation:

  • Use phosphatase inhibitors (sodium orthovanadate, sodium fluoride, β-glycerophosphate) in lysis buffers

  • Maintain samples at 4°C during processing to preserve phosphorylation

  • Consider using specialized phosphoprotein extraction buffers

• Loading controls:

  • Use total AR antibody on parallel blots or after stripping and reprobing

  • Include both phosphorylation-positive and negative control samples

• Blocking conditions:

  • Use 5% BSA in TBST rather than milk (which contains phosphatases) for blocking and antibody dilution

• Antibody incubation:

  • Dilute primary antibody (1:500-1:2000) in 5% BSA in TBST

  • Incubate overnight at 4°C for optimal sensitivity and specificity

• Detection system:

  • Consider enhanced chemiluminescence or fluorescent detection systems for optimal sensitivity

  • Quantify signals using image analysis software to determine relative phosphorylation levels

How can phosphatase treatment be used to validate Phospho-AR (Y363) Antibody specificity?

Phosphatase treatment is a crucial control for validating phospho-specific antibodies:

• Experimental design:

  • Split your sample into two equal portions

  • Treat one portion with lambda phosphatase or other suitable phosphatase

  • Maintain identical conditions except for phosphatase addition

• Protocol outline:

  • Resuspend protein samples in phosphatase buffer

  • Add active phosphatase to one sample and heat-inactivated phosphatase to the control

  • Incubate at 30°C for 30-60 minutes

  • Stop the reaction by adding phosphatase inhibitors and SDS sample buffer

  • Proceed with standard Western blot procedure

• Expected results:

  • Loss of signal in phosphatase-treated samples when probed with phospho-Y363 antibody

  • No change in signal when probed with total AR antibody

  • This confirms that the antibody specifically recognizes the phosphorylated form of AR

What are effective strategies for optimizing immunoprecipitation with Phospho-AR (Y363) Antibody?

While the search results don't specifically mention immunoprecipitation with this antibody, general principles for phospho-specific antibody IP include:

• Buffer optimization:

  • Use buffers containing phosphatase inhibitors (10mM sodium orthovanadate, 50mM NaF)

  • Include protease inhibitors to prevent protein degradation

  • Consider lower stringency lysis conditions (lower salt, milder detergents) to preserve interactions

• Antibody coupling:

  • Pre-couple antibody to protein A/G beads for cleaner IP results

  • Determine optimal antibody:bead ratio (typically 2-5 μg antibody per 20 μl bead slurry)

• IP procedure:

  • Pre-clear lysates with protein A/G beads to reduce non-specific binding

  • Perform IP at 4°C overnight with gentle rotation

  • Include appropriate negative controls (non-specific IgG, non-phosphorylated samples)

• Validation approaches:

  • Confirm presence of phosphorylated AR in IP eluate using a different AR antibody

  • Consider mass spectrometry analysis to confirm Y363 phosphorylation

How might AR Y363 phosphorylation influence prostate cancer progression?

While not directly addressed in the search results, the potential implications of AR Y363 phosphorylation in prostate cancer can be inferred:

• Altered AR activity:

  • Phosphorylation could modify AR transcriptional activity, potentially promoting expression of genes involved in cancer progression

  • Changes in AR activity could affect cancer cell proliferation, survival, or invasion

• Therapeutic resistance:

  • Phosphorylation events on AR are implicated in resistance to anti-androgen therapies

  • Y363 phosphorylation might provide a mechanism for ligand-independent AR activation

• Biomarker potential:

  • Levels of Y363 phosphorylation could serve as prognostic or predictive biomarkers

  • Monitoring changes in phosphorylation might help track disease progression or treatment response

• Therapeutic targeting:

  • Inhibiting the kinase responsible for Y363 phosphorylation could represent a novel therapeutic strategy

  • Combination approaches targeting both AR and its phosphorylation pathways might overcome resistance

Research to explore these possibilities would be valuable for understanding the role of AR Y363 phosphorylation in cancer biology.

How can in vitro ubiquitination assays be adapted to study the impact of AR Y363 phosphorylation?

Drawing from the methodology described for Cbl-b Y363 phosphorylation , an in vitro ubiquitination assay to study AR Y363 phosphorylation effects could be designed as follows:

• Protein preparation:

  • Express and purify AR protein (phosphorylated and non-phosphorylated forms)

  • Use site-directed mutagenesis to create Y363F mutant as a control

• Reaction components:

  • E1 ubiquitin-activating enzyme (0.25 μg)

  • E2 ubiquitin-conjugating enzyme (such as UbcH5B, 0.5 μg)

  • Purified AR protein (wild-type and Y363F)

  • Ubiquitin (preferably tagged for detection, 0.5 μg)

  • ATP regeneration system (1 mM ATP, 10 mM creatine phosphate, 10 μg creatine kinase)

  • Buffer (20 mM HEPES-KOH pH 7.5, 50 mM KCl, 5 mM MgCl2, 1 mM DTT)

• Assay procedure:

  • Combine reaction components and incubate at 30°C

  • Sample at multiple time points (0, 15, 30, 60, and 120 min)

  • Terminate reactions by adding SDS sample buffer

• Analysis:

  • Analyze by SDS-PAGE and Western blotting using antibodies against AR and ubiquitin

  • Quantify ubiquitination using densitometry

  • Compare ubiquitination rates between phosphorylated and non-phosphorylated AR

This approach would determine whether Y363 phosphorylation affects AR ubiquitination and potentially its stability.

What are potential interactions between AR Y363 phosphorylation and other post-translational modifications?

AR is subject to multiple post-translational modifications that may interact functionally with Y363 phosphorylation:

• Cross-talk with other phosphorylation sites:

  • AR contains multiple phosphorylation sites (S81, S213, S791, T850) that could influence or be influenced by Y363 phosphorylation

  • Sequential phosphorylation events could create complex regulatory patterns

• Ubiquitination:

  • Based on the Cbl-b model where "phosphorylation of Y363 regulates the E3 activity of Cbl-b" , AR Y363 phosphorylation might similarly affect its ubiquitination

  • This could alter AR stability and turnover

• Acetylation:

  • Acetylation of AR can modify its transcriptional activity

  • Y363 phosphorylation could create binding sites for acetyltransferases or influence existing acetylation sites

• SUMOylation:

  • AR SUMOylation generally represses transcriptional activity

  • Phosphorylation events can regulate SUMOylation of transcription factors

Experimental approaches to study these interactions could include:

• Mass spectrometry to identify co-occurring modifications

• Site-directed mutagenesis to create phosphomimetic and phosphodeficient mutants

• Inhibitor studies targeting specific enzymatic modifications

How might computational modeling help predict the structural consequences of AR Y363 phosphorylation?

Computational approaches can provide valuable insights into how Y363 phosphorylation affects AR structure and function:

• Molecular dynamics simulations:

  • Simulate the dynamic behavior of phosphorylated and non-phosphorylated AR

  • Predict changes in protein flexibility, domain organization, and interdomain interactions

• Docking studies:

  • Model interactions between phosphorylated AR and potential binding partners

  • Predict how phosphorylation creates or disrupts protein-protein interaction surfaces

• Electrostatic potential analysis:

  • Calculate how the negative charge of the phosphate group alters the local electrostatic environment

  • Similar to the findings for Cbl-b where "the phosphate group of pY363 is located in the vicinity of the interaction surface with UbcH5B to increase affinity by reducing their electrostatic repulsion"

• Structural prediction algorithms:

  • Predict secondary structure changes induced by phosphorylation

  • Identify potential conformational switches triggered by Y363 phosphorylation

These computational approaches could generate testable hypotheses about the structural and functional consequences of AR Y363 phosphorylation.

What are promising approaches for developing cell-based assays to monitor AR Y363 phosphorylation dynamics?

To monitor AR Y363 phosphorylation dynamics in live cells, researchers could develop:

• Phospho-specific biosensors:

  • FRET-based sensors that change conformation upon Y363 phosphorylation

  • Biosensors incorporating phospho-binding domains that interact specifically with phosphorylated Y363

• Reporter cell lines:

  • Generate stable cell lines expressing wild-type AR and Y363F mutant

  • Couple with luciferase reporters to monitor AR transcriptional activity

• Real-time imaging techniques:

  • Use fluorescently tagged antibody fragments that recognize phosphorylated Y363

  • Develop split-GFP complementation systems triggered by phosphorylation-dependent interactions

• Proximity-based assays:

  • Design BRET or FRET assays to detect interactions that depend on Y363 phosphorylation

  • Use proximity ligation assays to visualize Y363 phosphorylation in fixed cells

These approaches would enable dynamic monitoring of AR Y363 phosphorylation in response to various stimuli and perturbations.