Phospho-STK39 (S311) Antibody

What is STK39/SPAK and what is the significance of S311 phosphorylation?

STK39 (Serine/Threonine Kinase 39), also known as SPAK (STE20/SPS1-related Proline Alanine-rich Kinase), is a protein kinase involved in cellular osmotic stress responses and ion transport regulation. The phosphorylation at serine 311 (S311) represents a critical regulatory mechanism affecting the kinase's activity and downstream signaling pathways . This specific phosphorylation site plays an essential role in modulating the function of SPAK in various physiological contexts, including ion homeostasis, blood pressure regulation, and cellular stress responses. Understanding S311 phosphorylation provides valuable insights into how SPAK activity is regulated in both normal physiological states and pathological conditions such as hypertension and cancer .

What are the key characteristics of Anti-Phospho-SPAK (S311) STK39 Antibody?

The Anti-Phospho-SPAK (S311) STK39 Antibody is a polyclonal antibody raised in rabbits against a synthesized peptide derived from human STK39 around the phosphorylation site of Ser311 (amino acid range: 277-326) . It demonstrates reactivity in human, mouse, and rat samples, making it suitable for comparative studies across these species . The antibody is typically supplied in liquid form in PBS containing 50% glycerol, 0.5% BSA, and 0.02% sodium azide . It has been validated for various applications including Western Blotting (WB), Immunohistochemistry (IHC), and ELISA, with specific optimal dilution ratios for each technique (WB: 1:500-1:2000, IHC: 1:100-1:300, ELISA: 1:5000) .

How should the Phospho-STK39 (S311) Antibody be stored and handled to maintain optimal activity?

Proper storage and handling of the Phospho-STK39 (S311) Antibody is crucial for maintaining its specificity and sensitivity. For long-term storage, the antibody should be kept at -20°C for up to one year . For more frequent use and short-term storage, it can be maintained at 4°C for up to one month . It is essential to avoid repeated freeze-thaw cycles as these can lead to protein denaturation and loss of antibody activity . When handling the antibody, always use clean pipettes and sterile conditions to prevent contamination. Aliquoting the antibody into smaller volumes upon first thawing is recommended to minimize the number of freeze-thaw cycles. Before each use, gently mix the antibody solution by inverting the tube rather than vortexing, which can cause protein denaturation.

What are the optimal protocols for using Phospho-STK39 (S311) Antibody in Western Blotting?

For optimal Western Blotting results with Phospho-STK39 (S311) Antibody, follow this detailed protocol:

• Sample Preparation:

  • Extract proteins using RIPA buffer supplemented with phosphatase inhibitors

  • Quantify protein concentration using Bradford or BCA assay

  • Denature 20-50 μg protein in Laemmli buffer at 95°C for 5 minutes

• Gel Electrophoresis and Transfer:

  • Separate proteins on 10% SDS-PAGE (STK39 has a molecular weight of approximately 59.5 kDa)

  • Transfer to PVDF membrane at 100V for 90 minutes in cold transfer buffer

• Antibody Incubation:

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

  • Incubate with Phospho-STK39 (S311) Antibody at 1:1000 dilution (optimal range: 1:500-1:2000) in 5% BSA-TBST overnight at 4°C

  • Wash 3 times with TBST, 5 minutes each

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

  • Wash 3 times with TBST, 5 minutes each

• Detection:

  • Apply ECL substrate and detect signal using a digital imaging system

  • Expected band for phosphorylated STK39: ~59.5 kDa

• Controls:

  • Positive control: Lysates from cells treated with hypotonic stress or WNK1 activators

  • Negative control: Sample treated with lambda phosphatase

  • Loading control: β-actin or GAPDH

This protocol ensures specific detection of phosphorylated STK39 at S311 while minimizing background and non-specific binding.

How can I optimize immunohistochemistry protocols for Phospho-STK39 (S311) Antibody?

For optimal IHC results with Phospho-STK39 (S311) Antibody, follow this detailed protocol:

Tissue Preparation and Antigen Retrieval:

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

• Section tissues at 4-6 μm thickness

• Deparaffinize and rehydrate sections through xylene and graded alcohols

• Perform heat-induced epitope retrieval (HIER) using citrate buffer (pH 6.0) for 20 minutes at 95-100°C, as phospho-epitopes often require more stringent retrieval conditions

Antibody Incubation and Detection:

• Block endogenous peroxidase activity with 3% H₂O₂ for 10 minutes

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

• Incubate with Phospho-STK39 (S311) Antibody at 1:200 dilution (recommended range: 1:100-1:300) overnight at 4°C

• Wash 3 times with PBS, 5 minutes each

• Incubate with biotinylated secondary antibody for 30 minutes at room temperature

• Apply streptavidin-HRP conjugate for 30 minutes

• Develop with DAB substrate and counterstain with hematoxylin

Optimization Considerations:

• Perform antibody titration experiments (1:50, 1:100, 1:200, 1:300) to determine optimal concentration

• Test multiple antigen retrieval methods (citrate buffer pH 6.0, EDTA buffer pH 8.0, etc.)

• Include controls: phosphatase-treated sections as negative controls and tissues known to express phosphorylated STK39 as positive controls

• For fluorescent detection, use Alexa Fluor-conjugated secondary antibodies and include DAPI nuclear counterstain

The expected staining pattern should reflect the subcellular localization of phosphorylated STK39, which is primarily cytoplasmic with occasional nuclear presence depending on cell type and activation state.

What considerations are important when using Phospho-STK39 (S311) Antibody for ELISA applications?

When employing Phospho-STK39 (S311) Antibody in ELISA applications, several critical considerations must be addressed:

Protocol Optimization:

• Coating: Use high-binding ELISA plates coated with capture antibody (typically a total STK39 antibody) at 1-2 μg/ml in carbonate buffer (pH 9.6) overnight at 4°C

• Blocking: Block with 3% BSA in PBS for 1-2 hours at room temperature

• Sample preparation: Ensure samples contain phosphatase inhibitors and are processed consistently

• Phospho-STK39 (S311) Antibody dilution: Start with 1:5000 as recommended , but perform titration experiments (1:1000-1:10000) to determine optimal concentration

• Signal detection: Use HRP-conjugated secondary antibody and TMB substrate system for colorimetric detection

Critical Factors Affecting Sensitivity and Specificity:

• Phosphatase inhibitors must be included in all buffers to prevent dephosphorylation during sample processing

• Fresh samples generally yield better results than frozen samples

• Consider using synthetic phosphopeptides as standards for quantitative assays

• Include both positive controls (known phospho-STK39-containing samples) and negative controls (phosphatase-treated samples)

Data Analysis Considerations:

• Generate standard curves using known concentrations of phosphopeptides

• Account for total protein concentration when comparing phosphorylation levels between samples

• Calculate the ratio of phosphorylated to total STK39 when possible

• Perform statistical analysis to determine significance of differences between experimental groups

This methodological approach ensures accurate and reliable quantification of STK39 phosphorylation at S311 across experimental conditions.

How can I verify the specificity of the Phospho-STK39 (S311) Antibody for my experiments?

Verifying antibody specificity is crucial for reliable experimental results. For Phospho-STK39 (S311) Antibody, employ these validation strategies:

Phosphatase Treatment Controls:

• Divide your sample into two portions

• Treat one portion with lambda phosphatase to remove phosphate groups

• Run both treated and untreated samples on the same gel

• Loss of signal in the phosphatase-treated sample confirms phospho-specificity

Peptide Competition Assay:

• Pre-incubate the antibody with excess phospho-peptide (matching the immunogen sequence around S311)

• Use this mixture alongside the antibody alone in parallel experiments

• Significant signal reduction in the peptide-competition condition confirms epitope specificity

Genetic Validation:

• Use STK39 knockout models or CRISPR-Cas9 edited cells lacking STK39 or containing S311A mutation

• Absence of signal in these samples confirms target specificity

• If using siRNA knockdown, perform dose-response analysis to correlate signal reduction with STK39 protein reduction

Cross-Reactivity Testing:

• The antibody has been validated for reactivity in human, mouse, and rat samples

• When using in other species, perform careful validation studies

• Compare observed molecular weight (should be ~59.5 kDa) with predicted weight for the species of interest

Multiple Technique Validation:

• Confirm findings using at least two different techniques (e.g., WB and IHC)

• For each technique, use appropriate positive and negative controls

• Document all validation experiments thoroughly for publication purposes

What are common troubleshooting strategies for weak or non-specific signals when using Phospho-STK39 (S311) Antibody?

When encountering weak or non-specific signals with Phospho-STK39 (S311) Antibody, implement these systematic troubleshooting approaches:

For Weak or Absent Signals:

For Non-specific or High Background:

General Optimization Strategies:

• Gradual titration of antibody concentrations to determine optimal working dilution

• Testing different blocking agents (BSA, milk, serum) and concentrations

• Adjusting incubation times and temperatures

• Using freshly prepared buffers and reagents

• Including appropriate positive and negative controls in every experiment

By systematically addressing these potential issues, researchers can optimize their protocols to achieve specific and robust detection of phosphorylated STK39 at S311.

How can Phospho-STK39 (S311) Antibody be used to investigate signaling pathways in cancer research?

Phospho-STK39 (S311) Antibody serves as a valuable tool for investigating several critical signaling pathways in cancer research:

WNK-SPAK-NKCC1 Signaling Axis:
The phosphorylation of STK39/SPAK at S311 is a key event in the WNK kinase signaling cascade that regulates ion transporters such as NKCC1 . In cancer research, this pathway has significant implications:

• Monitor STK39 S311 phosphorylation to assess WNK kinase activity in tumor samples

• Correlate phosphorylation levels with tumor grade, invasion capacity, and metastatic potential

• Investigate how this pathway influences tumor microenvironment through osmotic regulation

Cell Volume Regulation and Survival:
STK39/SPAK phosphorylation mediates cell volume regulation, which affects cancer cell survival under various stress conditions:

• Study how chemotherapeutic agents affect STK39 phosphorylation status

• Investigate whether STK39 S311 phosphorylation confers resistance to apoptosis

• Develop combination therapies targeting cells with hyperphosphorylated STK39

Experimental Approaches:

• Phosphorylation Dynamics in Response to Treatment:

  • Treat cancer cell lines with various therapeutic agents

  • Monitor temporal changes in STK39 S311 phosphorylation using Western blotting

  • Correlate phosphorylation changes with cellular outcomes (apoptosis, cell cycle arrest)

• Spatial Distribution in Tumor Tissue:

  • Perform IHC on tumor microarrays using Phospho-STK39 (S311) Antibody

  • Compare phosphorylation patterns between tumor core and invasive front

  • Correlate with hypoxia markers and patient outcome data

• Functional Studies:

  • Generate phosphomimetic (S311D) and phospho-dead (S311A) STK39 mutants

  • Assess their effects on cancer cell migration, invasion, and drug sensitivity

  • Use Phospho-STK39 (S311) Antibody to verify endogenous phosphorylation status alongside mutant studies

By employing these approaches, researchers can gain deeper insights into how STK39/SPAK phosphorylation contributes to cancer progression and potentially identify novel therapeutic targets within this signaling network .

What are the best approaches for studying the cross-talk between STK39/SPAK phosphorylation and other metabolic signaling pathways?

Investigating the cross-talk between STK39/SPAK phosphorylation and other metabolic signaling pathways requires integrated experimental approaches:

Co-Immunoprecipitation Studies:

• Immunoprecipitate phosphorylated STK39 using Phospho-STK39 (S311) Antibody

• Analyze co-precipitating proteins by mass spectrometry to identify novel interaction partners

• Confirm interactions through reverse co-IP and proximity ligation assays

• Map the interactome under different metabolic conditions (glucose deprivation, insulin stimulation)

Phosphorylation Cascade Analysis:

• Develop a temporal map of phosphorylation events using Phospho-STK39 (S311) Antibody alongside antibodies for AMPK, mTOR, and insulin signaling components

• Use phosphatase and kinase inhibitors to manipulate specific nodes in these pathways

• Create a Bayesian network model of causal relationships between phosphorylation events

Metabolic Flux Analysis:

• Correlate STK39 S311 phosphorylation levels with metabolic parameters:

  • Glucose uptake (measure with 2-NBDG or radiolabeled glucose)

  • Glycolytic rate (Seahorse analysis)

  • Mitochondrial respiration (oxygen consumption rate)

• Compare wild-type cells with those expressing phosphomimetic or phospho-dead STK39 mutants

Multi-omics Integration:

Tissue-Specific Considerations:

• Liver: Focus on gluconeogenesis regulation and glucose homeostasis

• Kidney: Examine ion transport and blood pressure regulation mechanisms

• Adipose tissue: Investigate insulin sensitivity and lipolysis pathways

• Brain: Study neuronal excitability and neurotransmitter release

These approaches enable comprehensive mapping of how STK39/SPAK phosphorylation intersects with broader metabolic networks, potentially revealing new therapeutic targets for metabolic disorders .

How can quantitative analysis of STK39 S311 phosphorylation be implemented in clinical research studies?

Implementing quantitative analysis of STK39 S311 phosphorylation in clinical research requires standardized methodologies that ensure reliability and reproducibility across patient samples:

Sample Collection and Processing Protocol:

• Collect tissue biopsies or blood samples following standardized procedures

• Process samples immediately with phosphatase inhibitors to preserve phosphorylation status

• Use flash freezing for tissue samples or immediate protein extraction

• Maintain consistent processing times across all clinical samples

Quantitative Western Blotting:

• Implement fluorescence-based Western blotting with Phospho-STK39 (S311) Antibody

• Include recombinant phosphorylated STK39 standards at known concentrations

• Normalize phospho-signal to total STK39 (ratio approach)

• Use automated image analysis software for densitometric quantification

Multiplex Phosphoprotein Analysis:

• Develop multiplex assays incorporating Phospho-STK39 (S311) alongside other relevant phosphoproteins

• Options include:

  • Luminex bead-based assays

  • Reverse phase protein arrays (RPPA)

  • Mass cytometry (CyTOF) for single-cell resolution

• Include internal reference standards for cross-plate normalization

Clinical Correlation Analysis:

Quality Control Measures:

• Implement intra-assay and inter-assay controls

• Include phosphatase-treated negative controls

• Use multi-site validation for assay reproducibility

• Employ statistical methods that account for batch effects

Data Reporting Standards:

• Report phosphorylation as normalized ratio to total protein

• Provide detailed methodological documentation

• Include all quality control metrics

• Make raw data available for reanalysis

By implementing these quantitative approaches, clinical researchers can generate reliable data on STK39 S311 phosphorylation status that may serve as potential biomarkers for disease states or treatment responses in conditions related to metabolism, hypertension, and cancer .

What are the emerging research directions for Phospho-STK39 (S311) in translational medicine?

Emerging research directions for Phospho-STK39 (S311) in translational medicine span multiple promising avenues:

Biomarker Development:
The phosphorylation status of STK39 at S311 shows potential as a biomarker in several clinical contexts. Researchers are increasingly exploring its utility in:

• Hypertension risk stratification and treatment response prediction

• Cancer progression and therapeutic resistance monitoring

• Metabolic disorder phenotyping and personalized intervention design

Using the Phospho-STK39 (S311) Antibody in standardized assays allows for quantitative assessment of this potential biomarker across patient populations .

Therapeutic Target Validation:
As understanding of STK39/SPAK signaling pathways deepens, the S311 phosphorylation site emerges as a potential therapeutic target:

• Small molecule inhibitors preventing S311 phosphorylation are being developed for hypertension management

• Peptide-based strategies targeting this specific phosphorylation site show promise in preclinical models

• Combination approaches that modulate STK39 phosphorylation in concert with other therapeutic agents are being explored in cancer and metabolic disease contexts

Systems Biology Integration:
The role of STK39 S311 phosphorylation within broader cellular networks is becoming a focus for systems biology approaches:

• Network modeling incorporating phosphoproteomic data to position STK39 within signaling cascades

• Multi-omics integration to understand how S311 phosphorylation impacts cellular phenotypes

• Machine learning approaches to predict disease outcomes based on phosphorylation patterns

Clinical Implementation Considerations:
Researchers pursuing translational applications should consider:

• Standardization of phosphorylation detection methods across clinical laboratories

• Development of point-of-care testing platforms for rapid phosphorylation assessment

• Integration of phosphorylation data with electronic health records for longitudinal tracking

These emerging directions highlight the growing importance of STK39 S311 phosphorylation in translational medicine, bridging fundamental research with clinical applications across multiple disease domains .

How can researchers collaborate and share data related to STK39 phosphorylation studies?

Effective collaboration and data sharing strategies for STK39 phosphorylation studies can accelerate research progress through these structured approaches:

Standardized Reporting Protocols:

• Implement minimum information standards for phosphorylation studies, including:

  • Detailed antibody validation data for Phospho-STK39 (S311) Antibody

  • Complete experimental conditions and sample processing protocols

  • Raw data alongside processed results

  • Quality control metrics and threshold criteria

Data Repositories and Platforms:

• Deposit phosphoproteomics data in specialized repositories:

  • PRIDE (PRoteomics IDEntifications database)

  • PhosphoSitePlus for annotated phosphorylation sites

  • Cancer Proteome Atlas for clinical proteomics data

• Include detailed metadata about experimental conditions and antibody specifications

Collaborative Research Networks:

• Establish multi-institutional consortia focused on STK39 biology

• Implement sample sharing programs with standardized processing protocols

• Develop shared resources such as validated cell lines, animal models, and antibody validation datasets

Open Science Practices:

• Pre-register experimental protocols to reduce publication bias

• Share negative results related to STK39 phosphorylation studies

• Adopt open access publication models for enhanced accessibility

• Implement version control for protocols and analysis pipelines

Cross-Disciplinary Integration:

• Foster collaborations between:

  • Basic scientists studying molecular mechanisms

  • Clinical researchers with access to patient samples

  • Computational biologists for advanced data analysis

  • Pharmaceutical researchers exploring therapeutic applications

Technology Standardization:

• Develop reference standards for phosphorylated STK39

• Implement round-robin testing of Phospho-STK39 (S311) Antibody across laboratories

• Create standard operating procedures for sample processing and analysis

By implementing these collaborative approaches, researchers can build a more comprehensive understanding of STK39 phosphorylation biology and accelerate translational applications in hypertension, cancer, and metabolic disorders .

Technical Specifications for Phospho-STK39 (S311) Antibody