Phospho-CCNE2 (T392) Antibody

What is Cyclin E2 and why is its T392 phosphorylation significant?

Cyclin E2 (CCNE2) is a G1/S-specific cyclin that forms a complex with Cyclin-Dependent Kinase 2 (CDK2) to regulate cell cycle progression, particularly the transition from G1 to S phase. This complex phosphorylates multiple substrates including retinoblastoma protein (Rb), leading to E2F transcription factor release and S phase initiation . Threonine 392 phosphorylation is a specific post-translational modification located near the C-terminal region of Cyclin E2. While the exact functional significance of T392 phosphorylation isn't fully characterized, it likely plays a regulatory role similar to other cyclin phosphorylation sites that influence protein stability, localization, or interaction with binding partners .

How does the Phospho-CCNE2 (T392) antibody specifically detect phosphorylated Cyclin E2?

The Phospho-CCNE2 (T392) antibody is designed to recognize Cyclin E2 only when phosphorylated at the Threonine 392 position. This specificity is achieved through:

• Immunogen design: The antibody is generated using synthesized peptides derived from human Cyclin E2 around the phosphorylation site (amino acid range 355-404) .

• Affinity purification: The antibodies are affinity-purified from rabbit antiserum using epitope-specific immunogen chromatography to isolate only those antibodies that recognize the phosphorylated form .

• Validation: The specificity is confirmed through blocking experiments where the antibody signal disappears when pre-incubated with the phosphorylated peptide but remains when pre-incubated with non-phosphorylated peptides .

What are the recommended applications and dilutions for Phospho-CCNE2 (T392) antibody?

According to multiple product data sheets, the Phospho-CCNE2 (T392) antibody has been validated for the following applications:

The antibody is typically supplied in PBS containing 50% glycerol, 0.5% BSA, and 0.02% sodium azide, and should be stored at -20°C to -25°C .

How do Cyclin E1 and Cyclin E2 differ functionally?

Despite their structural similarities and apparent redundancy (demonstrated by embryonic lethality of double knockouts), Cyclin E1 and E2 show important differences :

These differences suggest distinct roles in specific biological contexts, with Cyclin E2 having unique functions in male fertility and polyploid cell regulation that cannot be compensated by Cyclin E1 .

How should I optimize immunofluorescence protocols using Phospho-CCNE2 (T392) antibody?

For optimal immunofluorescence results with Phospho-CCNE2 (T392) antibody:

• Fixation: Use 4% paraformaldehyde for 10-15 minutes at room temperature to preserve both protein localization and phosphorylation status .

• Permeabilization: Apply 0.1-0.2% Triton X-100 in PBS for 5-10 minutes to allow antibody access to nuclear proteins while preserving epitope integrity .

• Blocking: Use 5% BSA in PBS for 1 hour at room temperature to minimize non-specific binding.

• Antibody dilution: Start with 1:500 dilution and adjust based on signal intensity and background. The antibody diluent should contain 1% BSA and phosphatase inhibitors .

• Incubation time: Incubate with primary antibody overnight at 4°C for optimal specific binding.

• Controls: Include a blocking peptide control where the antibody is pre-incubated with the phosphorylated peptide, as demonstrated in the product validation images .

• Signal detection: Use fluorophore-conjugated secondary antibodies specific to rabbit IgG (as this is a rabbit polyclonal antibody) .

What controls should I include when working with phospho-specific antibodies?

When working with Phospho-CCNE2 (T392) antibody, include these essential controls:

• Blocking peptide control: Pre-incubate the antibody with phosphorylated peptide to demonstrate signal specificity. This is critical as shown in multiple product data sheets .

• Non-phosphorylated peptide control: Pre-incubate with the non-phosphorylated version of the same peptide, which should not block antibody binding.

• Phosphatase treatment control: Treat duplicate samples with lambda phosphatase to enzymatically remove phosphate groups; this should eliminate specific signal.

• Primary antibody omission: Include samples where only secondary antibody is applied to assess non-specific binding.

• Cell cycle synchronized controls: Include samples enriched for G1, S, and G2/M phases to correlate phosphorylation with cell cycle progression, as Cyclin E2 is a G1/S-specific cyclin .

• Genetic controls: When possible, include CCNE2 knockdown/knockout samples to confirm antibody specificity.

How can I troubleshoot non-specific binding or weak signals?

When troubleshooting issues with Phospho-CCNE2 (T392) antibody staining:

For high background/non-specific binding:

• Increase antibody dilution (try 1:800 or 1:1000 instead of 1:200)

• Extend washing steps (5 washes of 5 minutes each with PBS containing 0.1% Tween-20)

• Increase blocking time and concentration (use 5-10% BSA for 2 hours)

• Add 0.1% Tween-20 to antibody dilution buffer

• Pre-absorb secondary antibodies with cell/tissue lysate

For weak signals:

• Ensure phosphatase inhibitors are present in all buffers

• Decrease antibody dilution (try 1:200 if using 1:500)

• Increase incubation time (up to 48 hours at 4°C)

• Use signal amplification systems like tyramide signal amplification

• Optimize antigen retrieval (if using fixed tissues)

• Confirm your experimental conditions actually induce T392 phosphorylation

For cell cycle-specific signals:

• Synchronize cells to enrich for G1/S populations where Cyclin E2 is most active

• Include EdU or BrdU labeling to identify S-phase cells

How can I investigate the relationship between T392 phosphorylation and CDK2 activity?

To study the functional relationship between Cyclin E2 T392 phosphorylation and CDK2 activity:

• Time-course analysis: Use synchronized cells and collect samples at different time points throughout the cell cycle. Co-stain for T392-phosphorylated Cyclin E2 and CDK2 activity markers (such as the DHB sensor mentioned in the research literature) .

• CDK inhibitor studies: Treat cells with specific CDK2 inhibitors (such as PF-07104091 or PF-06873600) and monitor T392 phosphorylation changes. This approach has been successful for studying other CDK2 substrates .

• Phosphomimetic mutants: Generate T392D/E (phosphomimetic) or T392A (phospho-deficient) CCNE2 mutants and assess their impact on CDK2 binding and kinase activity using in vitro kinase assays.

• Co-immunoprecipitation: Use the Phospho-CCNE2 (T392) antibody to immunoprecipitate phosphorylated Cyclin E2 and examine co-precipitating CDK2, as well as the activity of the complex against substrates.

• Mass spectrometry: Perform quantitative phosphoproteomics to identify other phosphorylation events that correlate with T392 phosphorylation during CDK2 activation .

How can Phospho-CCNE2 (T392) antibody be used in cancer research?

The Phospho-CCNE2 (T392) antibody offers several valuable applications in cancer research:

• Biomarker identification: CCNE2 is frequently upregulated in various cancers with unique expression patterns distinct from Cyclin E1 . T392 phosphorylation could serve as a specific biomarker for certain cancer subtypes or stages.

• Treatment response monitoring: Assess changes in T392 phosphorylation following treatment with cell cycle inhibitors, particularly CDK4/6 inhibitors which are increasingly used in cancer therapy .

• Patient stratification: Compare T392 phosphorylation patterns across tumor samples to identify correlations with clinical outcomes, potentially identifying patient subgroups most likely to benefit from cell cycle-targeted therapies.

• Tumor microenvironment studies: Examine how T392 phosphorylation is affected by tumor microenvironment factors such as hypoxia, nutrient deprivation, or immune cell interactions.

• Multiplexed analysis: Combine Phospho-CCNE2 (T392) antibody with other cell cycle markers in immunofluorescence or flow cytometry to create comprehensive profiles of cell cycle dysregulation in different cancer types .

What approaches can I use to quantitatively measure T392 phosphorylation across different experimental conditions?

For quantitative assessment of T392 phosphorylation:

• ELISA-based quantification: Develop a sandwich ELISA using Phospho-CCNE2 (T392) antibody as the capture antibody and total Cyclin E2 antibody for detection, or vice versa. This approach has been successful for other phospho-specific targets .

• Flow cytometry: Perform intracellular staining with Phospho-CCNE2 (T392) antibody combined with DNA content analysis to quantify phosphorylation levels across different cell cycle phases .

• Western blot densitometry: Quantify band intensity of phosphorylated Cyclin E2 relative to total Cyclin E2 or housekeeping proteins across different experimental conditions.

• Immunofluorescence image analysis: Use automated image analysis software to quantify nuclear fluorescence intensity at the single-cell level, correlating with cell cycle markers .

• Phosphoproteomics: For absolute quantification, use targeted mass spectrometry approaches with isotopically labeled peptide standards corresponding to the phosphorylated and non-phosphorylated forms of the T392-containing peptide.

• High-content screening: Apply automated microscopy and image analysis to measure T392 phosphorylation across large sample sets, such as drug libraries or genetic perturbations.

How does T392 phosphorylation relate to other post-translational modifications of Cyclin E2?

The relationship between T392 phosphorylation and other Cyclin E2 modifications requires investigation using these approaches:

• Sequential immunoprecipitation: Use Phospho-CCNE2 (T392) antibody to immunoprecipitate phosphorylated Cyclin E2, then analyze other modifications (ubiquitination, additional phosphorylation sites) on this specific population.

• Mutational analysis: Generate T392A or T392D/E mutants and assess how they affect other modifications using western blot or mass spectrometry.

• Kinase/phosphatase screening: Identify the enzymes responsible for adding/removing the T392 phosphorylation, which may connect this modification to specific signaling pathways.

• Temporal profiling: Map the timing of T392 phosphorylation relative to other PTMs throughout the cell cycle, particularly in relation to the G1/S transition when Cyclin E2 is most active .

• Structural biology: Investigate how T392 phosphorylation might alter protein conformation and accessibility of other residues to modifying enzymes.

Understanding this PTM interplay could reveal complex regulatory mechanisms controlling Cyclin E2 function in normal cell cycle progression and in disease states.