Phospho-TGFBR2 (S225) Antibody

What is Phospho-TGFBR2 (S225) Antibody and what does it specifically detect?

Phospho-TGFBR2 (S225) Antibody specifically recognizes the TGF-beta receptor type-2 (TGFBR2) protein only when phosphorylated at serine residue 225. This antibody is crucial for studying post-translational modifications of TGFBR2 that affect receptor signaling dynamics. The antibody binds to the phosphorylated epitope surrounding the S225 residue, which is located within the amino acid range 191-240 of human TGFBR2 . Some antibodies detect both S225 and S250 phosphorylation sites . When selecting an antibody, researchers should verify the exact epitope recognized to ensure experimental specificity.

What are the available types and formats of Phospho-TGFBR2 (S225) antibodies?

Several formats of Phospho-TGFBR2 (S225) antibodies are available for research applications:

Most antibodies are provided in liquid form in PBS containing 50% glycerol, 0.5% BSA, and 0.02% sodium azide at a concentration of approximately 1 mg/mL . Both polyclonal and monoclonal options are available, with recombinant monoclonal antibodies offering increased specificity and reproducibility for critical applications .

What is the functional significance of TGFBR2 phosphorylation at S225?

TGFBR2 phosphorylation at S225 plays a crucial role in TGF-β signaling regulation. TGFBR2 is a transmembrane serine/threonine kinase that forms a heteromeric complex with TGFBR1 to transduce TGF-β signals from the cell surface to the cytoplasm .

The phosphorylation state of TGFBR2 at S225 affects:

• Complex formation between TGFBR1 and TGFBR2

• Activation of downstream SMAD-dependent and SMAD-independent signaling pathways

• Regulation of cellular processes including cell cycle arrest, differentiation, wound healing, and extracellular matrix production

Research indicates that TGFBR2 phosphorylation serves as a regulatory mechanism in TGF-β signaling cascades that influence both physiological and pathological processes, including cancer progression and fibrosis .

What are the recommended dilutions and conditions for using Phospho-TGFBR2 (S225) antibody in different applications?

Optimal working dilutions vary by application and specific antibody:

For Western blotting applications, researchers should expect a band at approximately 70-80 kDa, corresponding to phosphorylated TGFBR2 . When using the antibody for the first time, it is recommended to validate the specificity using appropriate positive and negative controls, such as lysates from cells treated with TGF-β (positive control) and lysates treated with alkaline phosphatase (negative control) .

How can researchers validate the specificity of Phospho-TGFBR2 (S225) antibody in their experimental system?

Several approaches can be employed to validate antibody specificity:

• Phosphatase treatment: Treat half of your sample with alkaline phosphatase to remove phosphorylation and compare detection between treated and untreated samples. Loss of signal confirms phospho-specificity .

• Stimulation experiments: Compare samples from unstimulated cells versus cells stimulated with TGF-β (10 μg) to induce TGFBR2 phosphorylation. An increase in signal intensity confirms antibody functionality .

• Peptide competition assay: Pre-incubate the antibody with the phosphorylated peptide used as the immunogen. This should abolish specific binding.

• Genetic validation: Use TGFBR2 knockout cells or tissues as negative controls, or cells expressing TGFBR2 with S225A mutation that prevents phosphorylation.

• Multiple detection methods: Confirm findings using complementary techniques (e.g., if using WB, validate with IHC or IF).

What positive controls are recommended for Phospho-TGFBR2 (S225) antibody validation?

Based on the search results and literature:

• For Western blot: HepG2 cells treated with TGF-β (10 μg) show detectable phosphorylation of TGFBR2 at S225 .

• For IHC-P applications: Human brain tissue is suggested as a positive control .

• For cell line controls: Cell lines with known high expression of TGFBR2 and active TGF-β signaling can be used, particularly after stimulation with TGF-β ligand.

When comparing controls, researchers should observe a band between 70-80 kDa in positive samples, which is reduced or absent in negative controls such as phosphatase-treated samples or unstimulated cells .

How can phosphorylation of TGFBR2 at S225 be distinguished from other phosphorylation sites?

Distinguishing between different phosphorylation sites on TGFBR2 requires careful experimental design:

• Use site-specific antibodies: Select antibodies that specifically recognize S225 phosphorylation rather than dual-specificity antibodies that detect both S225 and S250 phosphorylation .

• Mass spectrometry analysis: For definitive identification, phosphopeptide mapping using mass spectrometry can precisely identify and quantify site-specific phosphorylation.

• Mutagenesis studies: Create point mutations (S225A, S250A, or double mutations) and compare phosphorylation patterns to determine site-specific effects.

• Phosphatase treatment followed by site-specific detection: Selectively inhibit specific phosphatases to determine which enzymes regulate each phosphorylation site.

Research has shown that S225 and S250 may have distinct functional roles in TGFBR2 signaling, making it important to distinguish between them in mechanistic studies .

What are the key considerations when studying TGFBR2 phosphorylation in the context of TGF-β signaling pathway analysis?

When investigating TGFBR2 phosphorylation in TGF-β signaling:

• Temporal dynamics: TGFBR2 phosphorylation occurs with specific timing after TGF-β stimulation. Time-course experiments are essential to capture the dynamic nature of these modifications.

• Context dependency: TGFBR2 phosphorylation patterns may vary significantly between cell types and tissues. Controls should include tissue-specific validation.

• Complex formation analysis: TGFBR2 functions in complex with TGFBR1. Co-immunoprecipitation experiments can determine how S225 phosphorylation affects receptor complex formation .

• Cross-pathway integration: Examine how TGFBR2 phosphorylation interacts with other signaling pathways, such as MAPK or PI3K, which can modulate TGF-β responses.

• Downstream effector analysis: Assess how S225 phosphorylation influences both canonical (SMAD-dependent) and non-canonical (SMAD-independent) TGF-β signaling pathways .

Research by Chandrasekaran et al. demonstrated that TGFBR2 also phosphorylates BUB1 at Serine-318, which affects the interaction between BUB1, TGFBR1, and SMAD2, suggesting complex regulatory mechanisms involving TGFBR2 kinase activity .

How do results from Phospho-TGFBR2 (S225) antibody detection correlate with TGFBR2 function in disease models?

Research correlating TGFBR2 phosphorylation with disease progression shows:

• Cancer progression: Altered TGFBR2 phosphorylation patterns have been observed in various cancers, potentially contributing to the switch from TGF-β's tumor-suppressive to tumor-promoting effects .

• Fibrotic disorders: Dysregulated TGFBR2 phosphorylation may contribute to excessive TGF-β signaling in fibrotic diseases affecting multiple organs.

• Developmental disorders: Mutations affecting TGFBR2 phosphorylation sites have been linked to Loeys-Dietz syndrome, Marfan syndrome, and other connective tissue disorders .

• Prostate cancer lineage plasticity: Studies in mouse models lacking Pten and Tgfbr2 showed increased expression of stem cell markers and basal epithelial cell genes, suggesting TGF-β signaling limits lineage plasticity in prostate cancer .

When analyzing phosphorylation data in disease contexts, researchers should consider both gain and loss of phosphorylation at S225 and correlate findings with functional readouts of TGF-β signaling activity.

What are the main factors affecting the sensitivity and specificity of Phospho-TGFBR2 (S225) antibody detection?

Several factors influence antibody performance:

• Sample preparation:

  • Fresh samples typically yield better results than archived materials

  • Phosphatase inhibitors must be included during sample preparation to preserve phosphorylation status

  • Rapid fixation minimizes post-mortem dephosphorylation

• Antibody quality:

  • Batch-to-batch variation can occur, particularly with polyclonal antibodies

  • Monoclonal antibodies like EPR12198 offer greater consistency

  • Storage conditions and freeze-thaw cycles can impact antibody performance

• Protocol optimization:

  • Antigen retrieval methods significantly impact phospho-epitope detection in fixed tissues

  • Blocking reagents must be carefully selected to prevent non-specific binding

  • Signal amplification systems should be calibrated to the expected phosphorylation level

• Detection systems:

  • Enhanced chemiluminescence (ECL) sensitivity varies by manufacturer

  • Fluorescent secondary antibodies may offer improved quantification capabilities

  • Tyramide signal amplification can increase sensitivity for low-abundance phosphorylation events

How can researchers quantitatively analyze Phospho-TGFBR2 (S225) levels in complex biological samples?

Quantitative assessment requires rigorous methodology:

• Normalization approaches:

  • Normalize phospho-TGFBR2 signal to total TGFBR2 levels to account for expression differences

  • Use multiple housekeeping controls appropriate for your experimental system

  • Consider normalizing to sample loading by total protein staining methods (e.g., SYPRO Ruby, Ponceau S)

• Densitometric analysis:

  • Use linear range calibration standards for accurate quantification

  • Multiple exposure times may be necessary to ensure linearity of signal

  • Software like ImageJ with appropriate background correction is recommended

• Absolute quantification:

  • Phosphopeptide standards can be used for absolute quantification by mass spectrometry

  • ELISA-based quantification allows for higher sample throughput

  • Proximity ligation assays offer sensitive detection of phosphorylated proteins in situ

• Statistical considerations:

  • Biological replicates (n≥3) are essential for reliable quantification

  • Appropriate statistical tests should account for the distribution of phosphorylation data

  • Power calculations should guide sample size determination

What are the most effective strategies for multiplexing Phospho-TGFBR2 (S225) detection with other signaling pathway components?

Effective multiplexing strategies include:

• Sequential immunoblotting:

  • Careful stripping and reprobing protocols that preserve phospho-epitopes

  • Use of antibodies from different host species to allow simultaneous detection

  • Employment of differentially labeled secondary antibodies for spectral separation

• Multiplex immunofluorescence:

  • Tyramide signal amplification with sequential staining for multiple phospho-epitopes

  • Spectral unmixing to separate overlapping fluorophore emissions

  • Confocal microscopy for improved spatial resolution of co-localization

• Mass cytometry (CyTOF):

  • Metal-conjugated antibodies allow simultaneous detection of >40 parameters

  • Phospho-specific antibodies can be combined with lineage markers

  • Single-cell analysis of phosphorylation networks

• Proximity-based assays:

  • Proximity ligation assays detect interactions between phosphorylated TGFBR2 and binding partners

  • BRET/FRET approaches for live-cell monitoring of phosphorylation dynamics

  • BiFC (Bimolecular Fluorescence Complementation) to visualize complex formation dependent on phosphorylation

Multiplexing is particularly valuable when examining how TGFBR2 phosphorylation relates to SMAD activation and non-canonical pathway components, providing a systems-level view of TGF-β signaling dynamics .

How might new technological advances enhance the detection and functional analysis of TGFBR2 phosphorylation?

Emerging technologies offer promising approaches:

• Super-resolution microscopy: Techniques like STORM and PALM can visualize nanoscale distribution of phosphorylated TGFBR2 in relation to signaling partners, revealing spatial organization previously undetectable.

• CRISPR-Cas9 phosphosite engineering: Precise genome editing to create endogenous phosphomutants (S225A) or phosphomimetics (S225D/E) allows physiological examination of site-specific functions without overexpression artifacts.

• Optogenetic control of phosphorylation: Light-controlled kinase or phosphatase recruitment systems enable temporal control of TGFBR2 phosphorylation states to study dynamics.

• Single-cell phosphoproteomics: Technologies for analyzing phosphorylation events at single-cell resolution will reveal heterogeneity in TGFBR2 phosphorylation within tissues.

• Spatial transcriptomics integration: Correlating spatial patterns of TGFBR2 phosphorylation with transcriptional responses provides insights into localized signaling effects.

These advanced approaches will help resolve outstanding questions about how TGFBR2 phosphorylation at S225 contributes to cellular decisions in development, homeostasis, and disease .

What are the unresolved questions regarding TGFBR2 S225 phosphorylation in TGF-β signaling biology?

Despite extensive research, several key questions remain:

• Kinase identification: The specific kinase(s) responsible for S225 phosphorylation under different physiological and pathological conditions remain incompletely characterized.

• Phosphatase regulation: The phosphatases that dephosphorylate S225 and how they are regulated in different cellular contexts require further investigation.

• Crosstalk mechanisms: How S225 phosphorylation interacts with other TGFBR2 modifications (such as ubiquitination, sumoylation, or additional phosphorylation sites) remains unclear.

• Isoform-specific effects: How S225 phosphorylation differentially affects the three known TGFBR2 isoforms and their signaling properties requires additional research .

• Translational potential: Whether targeting S225 phosphorylation could provide therapeutic benefits in diseases with dysregulated TGF-β signaling needs exploration.

Addressing these questions will enhance our understanding of the nuanced regulatory mechanisms in TGF-β signaling and potentially reveal new therapeutic targets .