PPP1R2 (Ab-44) Antibody

What is the PPP1R2 (Ab-44) Antibody and what epitope does it recognize?

PPP1R2 (Ab-44) Antibody is a rabbit polyclonal antibody that recognizes endogenous levels of total PPP1R2 protein (also known as Inhibitor-2, IPP-2, or IPP2). The antibody was developed using a synthesized peptide derived from an internal region of human PPP1R2 as the immunogen . This antibody has been affinity-purified from rabbit antiserum using epitope-specific affinity chromatography, which enhances its specificity while minimizing cross-reactivity . It binds to an internal region of the PPP1R2 protein, making it suitable for detecting the native protein in its cellular context rather than just denatured forms.

What are the validated applications for PPP1R2 (Ab-44) Antibody?

The PPP1R2 (Ab-44) Antibody has been validated primarily for Western Blot (WB) applications, with successful detection demonstrated in multiple cell lines including COLO cells, HepG2 cells, and HUVEC cells . Some PPP1R2 antibodies are also validated for ELISA applications, though specific validation data for the Ab-44 variant in ELISA is limited . For Western blot applications, the recommended dilution range is typically 1:500-1:1000, though optimal dilutions should be determined empirically for each experimental setup .

What controls should be included when using PPP1R2 (Ab-44) Antibody in Western blot experiments?

When designing Western blot experiments with PPP1R2 (Ab-44) Antibody, several controls should be incorporated:

• Positive control: Cell lysates from validated cell lines such as COLO, HepG2, or HUVEC cells, which have been confirmed to express detectable levels of PPP1R2 .

• Negative control: Either samples known to lack PPP1R2 expression or primary antibody omission control to assess non-specific binding of secondary antibodies.

• Loading control: Detection of housekeeping proteins (e.g., GAPDH, β-actin) to ensure equal loading across lanes.

• Specificity control: Preincubation of the antibody with the immunizing peptide to demonstrate binding specificity.

• Molecular weight marker: To confirm that the detected band appears at the expected molecular weight of PPP1R2 (approximately 23 kDa).

Including these controls helps validate experimental results and provides confidence in the specificity of detected signals.

How can I optimize protein extraction to effectively detect PPP1R2 in different cellular fractions?

Optimizing protein extraction for PPP1R2 detection requires consideration of its subcellular localization and protein interactions:

• Whole cell lysates: Use RIPA buffer (150mM NaCl, 1% NP-40, 0.5% sodium deoxycholate, 0.1% SDS, 50mM Tris pH 8.0) supplemented with protease inhibitors and phosphatase inhibitors (particularly important as PPP1R2 is regulated by phosphorylation).

• Nuclear fractions: Since PPP1R2 forms complexes with nuclear proteins like RepoMan , nuclear extraction buffers containing 420mM NaCl, 20mM HEPES pH 7.9, 1.5mM MgCl₂, 0.2mM EDTA, and 25% glycerol may improve detection of nuclear PPP1R2 complexes.

• Sample preparation: To preserve protein-protein interactions for co-immunoprecipitation studies, gentler lysis buffers (e.g., 150mM NaCl, 20mM Tris pH 7.5, 1mM EDTA, 1mM EGTA, 1% Triton X-100) are recommended.

• Denaturing conditions: When detecting total PPP1R2 regardless of complex formation, include 2% SDS and boil samples before loading to ensure complete denaturation and maximize epitope accessibility.

• Phosphorylation-specific detection: If interested in phosphorylated forms of PPP1R2, include phosphatase inhibitors (sodium orthovanadate, sodium fluoride, β-glycerophosphate) in all buffers to prevent dephosphorylation during extraction.

What troubleshooting approaches are recommended when PPP1R2 detection is suboptimal?

When encountering difficulties with PPP1R2 (Ab-44) Antibody performance, consider these troubleshooting strategies:

• Antibody concentration: Adjust the dilution factor within the recommended range (1:500-1:1000) . For weak signals, decrease dilution; for high background, increase dilution.

• Protein loading: Increase total protein amount to 30-50μg per lane when detecting low-abundance PPP1R2.

• Transfer optimization: Use PVDF membranes (0.45μm pore size) instead of nitrocellulose for better protein retention, and optimize transfer conditions (20% methanol, 25V for 16h at 4°C) for efficient transfer of mid-size proteins.

• Signal enhancement: Implement signal enhancement systems (e.g., biotin-streptavidin amplification) or use highly sensitive ECL substrates for low-abundance detection.

• Membrane blocking: Test alternative blocking agents (5% non-fat milk vs. 3-5% BSA) to reduce background while maintaining specific signal.

• Sample preparation: Ensure complete protein denaturation by adding fresh reducing agents (DTT or β-mercaptoethanol) to sample buffer and heating at 95°C for 5 minutes.

• Alternative antibody: If persistent issues occur, consider using alternative PPP1R2 antibodies targeting different epitopes, such as those against Ab-120/121 region .

How does PPP1R2 function in PP1 holoenzyme stabilization, and how can this be studied using PPP1R2 (Ab-44) Antibody?

PPP1R2 has been shown to modulate PP1 function through stabilization of specific PP1 holoenzymes, which contradicts its classical designation as merely an inhibitor . To study this complex biological role:

• Co-immunoprecipitation studies: Use PPP1R2 (Ab-44) Antibody to immunoprecipitate PPP1R2 and associated proteins, followed by Western blot detection of PP1 and other binding partners like RepoMan, PNUTS, URI, and components of the GCN2/eIF2β complex .

• Proximity ligation assays: Combine PPP1R2 (Ab-44) Antibody with antibodies against PP1 or RepoMan to visualize and quantify protein-protein interactions in situ using fluorescence microscopy.

• Phosphorylation analysis: Compare PPP1R2-associated PP1 activity in the presence of different phosphorylation states of PPP1R2 (especially at Ser120/Ser121), which can be detected using phospho-specific antibodies .

• Holoenzyme stability assays: Use PPP1R2 (Ab-44) Antibody in Western blots following size-exclusion chromatography to analyze how PPP1R2 affects the stability and composition of PP1 holoenzyme complexes under varying ionic strength conditions.

Research has demonstrated that PPP1R2 disrupts an inhibitory interaction between PP1's C-terminal tail and catalytic domain, generates additional interaction sites, and stabilizes holoenzymes through direct PPP1R2:RepoMan interactions . These mechanisms collectively promote the dephosphorylation of specific substrates by enhancing holoenzyme stability rather than simply inhibiting PP1 activity.

What are the implications of PPP1R2 in cell proliferation pathways, and how can PPP1R2 (Ab-44) Antibody be used to investigate these mechanisms?

Research has revealed that PPP1R2 plays a critical role in cell proliferation, with its depletion or mutation of its PP1-binding domain leading to reduced proliferation and hyperphosphorylation of key substrates including PP1 itself and histone H3T3 . To investigate these proliferation-related pathways:

• Cell cycle analysis: Use PPP1R2 (Ab-44) Antibody in combination with cell cycle markers to determine how PPP1R2 expression levels correlate with different cell cycle phases through immunofluorescence or flow cytometry.

• Phosphoproteomics: Following PPP1R2 knockdown or overexpression, use the antibody to confirm manipulation success, then conduct phosphoproteomic analysis to identify differentially phosphorylated substrates dependent on PPP1R2 function.

• Chromatin immunoprecipitation (ChIP): Since PPP1R2 affects H3T3 phosphorylation status , use PPP1R2 (Ab-44) Antibody in ChIP experiments to investigate chromatin association of PPP1R2-containing complexes and correlate with gene expression patterns.

• CRISPR-based functional screens: Create cellular models with PPP1R2 mutations in the PP1-binding HYNE motif, similar to the R2-HYNEm knock-in cell lines described in the literature , and use the antibody to validate the models before phenotypic characterization.

The study of PPP1R2's role in proliferation pathways has particular relevance for cancer research, as dysregulation of phosphatase activity is implicated in numerous malignancies, making PPP1R2 a potential target for therapeutic intervention.

How can PPP1R2 (Ab-44) Antibody be utilized in studying the interaction network of PPP1R2 beyond PP1 binding?

Recent proteomics research has identified multiple PPP1R2-containing complexes beyond its canonical interaction with PP1 . The PPP1R2 (Ab-44) Antibody can be employed to investigate this expanded interaction network:

• Mass spectrometry-based interactomics: Use the antibody for immunoprecipitation followed by mass spectrometry to identify novel PPP1R2 interacting partners under different cellular conditions (e.g., cell cycle phases, stress responses).

• Validation of interactions: Following identification of potential interactors, use reciprocal co-immunoprecipitation with PPP1R2 (Ab-44) Antibody to confirm direct interactions with components of the:

  • GCN2/eIF2β complex (eIF2α, eIF2β, eIF2γ, GCN2)

  • PNUTS/PTW complex (PNUTS, TOX4, WDR82)

  • RepoMan complex (PPP2R5/B56, RepoMan)

  • URI/PPP1R19 complex (ASDURF, PDRG1, PFDN2, PFDN6, POLR2E, RPAP3, URI, UXT)

• Domain mapping: Combine the antibody with truncated PPP1R2 constructs to determine which regions of PPP1R2 mediate specific protein-protein interactions.

• Functional assays: Use the antibody to monitor endogenous PPP1R2 levels while manipulating expression of identified interactors to establish functional relationships and hierarchy within signaling networks.

These approaches can uncover how PPP1R2 functions as a hub protein connecting various cellular processes through its diverse interaction network, extending its role beyond simple PP1 regulation to coordinating broader cellular signaling pathways.

What methodological approaches are recommended for investigating PPP1R2 phosphorylation states using complementary antibodies?

PPP1R2 function is regulated by phosphorylation at multiple sites, particularly Ser120/Ser121 . To comprehensively study these modifications:

• Complementary antibody selection: Use PPP1R2 (Ab-44) Antibody for total protein detection alongside phospho-specific antibodies targeting Ser120/Ser121 to determine phosphorylation ratios.

• Sequential immunoblotting: First probe with phospho-specific antibodies, then strip and reprobe with the total PPP1R2 (Ab-44) Antibody to normalize phosphorylation signals to total protein levels from the same membrane.

• Phosphatase treatment controls: Include samples treated with lambda phosphatase to demonstrate phosphorylation specificity of detected bands.

• Kinase inhibition studies: Combine PPP1R2 (Ab-44) Antibody detection with kinase inhibitor treatments (e.g., GSK3 inhibitors) to identify regulatory pathways controlling PPP1R2 phosphorylation.

• 2D gel electrophoresis: Separate proteins first by isoelectric point to resolve different phosphorylation states, then by molecular weight, followed by immunoblotting with PPP1R2 (Ab-44) Antibody to visualize the full complement of PPP1R2 isoforms.

This multi-antibody approach provides a more complete picture of PPP1R2 regulation through its phosphorylation cycle and how these modifications affect its binding to PP1 and other interacting proteins.

How can PPP1R2 (Ab-44) Antibody be implemented in high-content screening approaches to identify modulators of PP1 regulatory networks?

High-content screening approaches using PPP1R2 (Ab-44) Antibody can accelerate discovery of pathways regulating PP1:PPP1R2 complexes:

• Automated immunofluorescence screening: Establish a high-throughput immunofluorescence protocol using PPP1R2 (Ab-44) Antibody to monitor subcellular localization changes in response to chemical or genetic perturbations.

• Multiplex detection systems: Combine PPP1R2 (Ab-44) Antibody with antibodies against PP1 and substrate phosphorylation (e.g., H3T3) in multiplex immunoassays to simultaneously track multiple components of the pathway.

• BRET/FRET-based interaction assays: Develop biosensor systems that incorporate recognition by PPP1R2 (Ab-44) Antibody to detect conformational changes in PPP1R2-containing complexes in real-time.

• Phenotypic correlation: Link quantitative readouts of PPP1R2 levels (detected by the antibody) with cellular phenotypes such as proliferation rates, cell cycle distribution, or chromosome segregation errors.

• Validation methodology: Implement a multi-tier validation strategy where hits from primary screens are confirmed by secondary assays using PPP1R2 (Ab-44) Antibody in lower-throughput but higher-precision techniques like Western blotting.

These approaches can identify novel modulators of the PP1:PPP1R2 axis that might have therapeutic potential, particularly in proliferative disorders where phosphatase dysregulation plays a causative role.

What are the considerations for using PPP1R2 (Ab-44) Antibody in combination with super-resolution microscopy to visualize PP1 holoenzyme dynamics?

Super-resolution microscopy combined with PPP1R2 (Ab-44) Antibody immunofluorescence can provide unprecedented insights into holoenzyme spatial organization:

• Sample preparation optimization: For techniques like STORM or PALM, optimize fixation protocols (typically 4% paraformaldehyde for 10 minutes at room temperature followed by 0.1% Triton X-100 permeabilization) to maintain epitope accessibility while preserving spatial organization.

• Multi-color labeling strategy: Design co-localization experiments using PPP1R2 (Ab-44) Antibody with complementary antibodies against PP1 catalytic subunit and substrate proteins, using spectrally distinct fluorophores compatible with the super-resolution system.

• Validation controls: Include antibody specificity controls through siRNA knockdown of PPP1R2 to confirm signal specificity at nanoscale resolution.

• Dynamic analysis: Combine with live-cell imaging approaches by developing knock-in cell lines expressing fluorescent-tagged proteins that preserve epitope recognition by PPP1R2 (Ab-44) Antibody in fixed timepoints.

• Quantitative analysis pipeline: Establish computational workflows to quantify spatial relationships between PPP1R2, PP1, and substrates at nanometer resolution, including measurements of clustering, inter-molecular distances, and co-localization coefficients.

These advanced imaging approaches can reveal how PPP1R2-containing holoenzymes assemble and disassemble dynamically throughout the cell cycle, particularly during mitosis when PPP1R2-RepoMan interactions play critical roles in chromosome segregation through regulation of H3T3 phosphorylation .

How might PPP1R2 (Ab-44) Antibody contribute to understanding the role of PPP1R2 in disease contexts beyond cancer?

While PPP1R2's role in proliferation has implications for cancer research, its function extends to other disease contexts that can be investigated using the PPP1R2 (Ab-44) Antibody:

• Neurodegenerative disorders: Given PP1's role in tau phosphorylation, use the antibody to examine PPP1R2 expression and localization in Alzheimer's disease models and patient samples.

• Metabolic diseases: Investigate how PPP1R2 regulates eIF2α phosphorylation through the GCN2/eIF2β complex in models of diabetes and obesity, where translational control is dysregulated.

• Cardiac pathologies: Study PPP1R2 expression and phosphorylation status in heart failure models, where phosphatase activity critically regulates calcium handling and contractility.

• Inflammatory conditions: Examine how PPP1R2-mediated PP1 regulation affects NF-κB signaling pathways in chronic inflammatory diseases through regulation of IκB phosphorylation.

• Biomarker development: Explore the potential of PPP1R2 protein levels or phosphorylation status (detected using PPP1R2 (Ab-44) Antibody in combination with phospho-specific antibodies) as diagnostic or prognostic biomarkers in various pathological conditions.

These investigations could reveal new therapeutic targets within the PPP1R2-PP1 regulatory axis across diverse disease states.

What experimental approaches can integrate PPP1R2 (Ab-44) Antibody with emerging technologies for spatial proteomics?

Emerging spatial proteomics technologies can be integrated with PPP1R2 (Ab-44) Antibody to provide unprecedented insights:

• Mass cytometry (CyTOF): Conjugate PPP1R2 (Ab-44) Antibody with rare earth metals for high-dimensional analysis of PPP1R2 expression across heterogeneous cell populations alongside dozens of other proteins.

• Spatial transcriptomics correlation: Combine immunofluorescence using PPP1R2 (Ab-44) Antibody with in situ RNA sequencing to correlate protein localization with transcriptional profiles at single-cell resolution.

• Proximity-dependent labeling: Use PPP1R2 (Ab-44) Antibody to validate results from BioID or APEX2 proximity labeling experiments where PPP1R2 is used as the bait protein to map its protein interaction neighborhood.

• Single-cell proteomics: Develop protocols for using PPP1R2 (Ab-44) Antibody in single-cell Western blot or single-cell proteomics workflows to examine cell-to-cell variability in PPP1R2 expression and modification states.

• Cryo-electron tomography correlation: Combine immunogold labeling using PPP1R2 (Ab-44) Antibody with cryo-electron tomography to visualize PPP1R2-containing complexes in their native cellular context at near-atomic resolution.

These cutting-edge approaches would significantly advance our understanding of how PPP1R2 functions within its spatial and temporal contexts in cells.