PPP1R14C Antibody

What are the recommended applications for PPP1R14C antibodies?

PPP1R14C antibodies have been validated for multiple research applications, including:

• Western Blotting (WB): Primary application for detecting PPP1R14C protein expression levels

• Immunohistochemistry (IHC): For tissue localization and expression analysis

• Immunofluorescence (IF): For subcellular localization studies

• ELISA: For quantitative protein detection

• Immunocytochemistry (ICC): For cellular localization in cultured cells

Working dilutions vary by application and antibody source, but typical ranges include:

• WB: 1:500-1:2000

• IHC: 1:100-1:300

• IF: 1:200-1:1000

• ELISA: 1:20000

What is known about the molecular characteristics of PPP1R14C?

PPP1R14C has the following molecular characteristics:

• Molecular weight: Approximately 17.8 kDa

• Length: 165 amino acid residues in humans (canonical form)

• Subcellular localization: Membrane and cytoplasm

• Structure: Contains an RVXF motif (residues 20-24; RVFFQ) that mediates binding to PP1

• Key phosphorylation site: Threonine 73 (T73), which is critical for its inhibitory activity against PP1

• Superfamily: PP1 inhibitor family

• Post-translational modifications: Primarily phosphorylation

The protein contains functional domains including the PP1-binding motif and phosphorylation sites that regulate its activity as a PP1 inhibitor .

How should PPP1R14C antibodies be validated for research applications?

Comprehensive validation of PPP1R14C antibodies should follow these methodological approaches:

• Specificity verification:

  • Western blot analysis with positive controls (TNBC cell lines) and negative controls (normal breast tissue)

  • Testing on knockout/knockdown samples to confirm specificity

  • Peptide competition assays using the immunizing peptide

• Cross-reactivity assessment:

  • Testing antibody reactivity across multiple species (human, mouse, rat) to confirm cross-reactivity claims

  • Using cell lines with varying PPP1R14C expression levels

• Application-specific validation:

  • For IHC: Test on FFPE tissues with known PPP1R14C expression patterns

  • For IF: Confirm subcellular localization consistent with literature

  • For WB: Verify band size at expected molecular weight (~17.8 kDa)

Researchers should apply rigorous controls, including secondary antibody-only controls and isotype controls, to rule out non-specific binding .

What experimental conditions optimize PPP1R14C detection in Western blotting?

For optimal detection of PPP1R14C by Western blotting:

• Sample preparation:

  • Use RIPA or NP-40 buffer supplemented with protease and phosphatase inhibitors

  • Include phosphatase inhibitors if detecting phosphorylated forms

• Electrophoresis conditions:

  • Use 12-15% SDS-PAGE gels due to PPP1R14C's low molecular weight (17.8 kDa)

  • Include positive controls from TNBC cell lines (e.g., MDA-MB-231, SUM159PT)

• Transfer parameters:

  • Semi-dry or wet transfer with PVDF membrane recommended

  • Short transfer times (60-90 minutes) at lower voltage

• Blocking and antibody incubation:

  • 5% non-fat milk or BSA in TBST (5% BSA preferred when detecting phosphorylated forms)

  • Primary antibody incubation at 4°C overnight at dilutions of 1:500-1:2000

  • Wash thoroughly with TBST before secondary antibody application

Researchers should optimize conditions based on their specific antibody source and sample type.

What are the best methods for analyzing PPP1R14C expression in tumor tissues?

For analyzing PPP1R14C expression in tumor tissues, researchers should consider:

• Immunohistochemistry protocols:

  • Antigen retrieval: Citrate buffer (pH 6.0) or EDTA buffer (pH 9.0)

  • Antibody dilution: 1:100-1:300 range, optimized for each antibody

  • Detection system: ABC or polymer-based detection systems

  • Counterstaining: Hematoxylin for nuclear visualization

• Evaluation methods:

  • Staining index (SI) calculation based on staining intensity (0-3) and percentage of positive cells

  • SI ≥ 6 often used as cutoff for high PPP1R14C expression

  • Compare expression between tumor and adjacent normal tissues

• Correlation with clinicopathological parameters:

  • T stage

  • Lymph node status

  • Histological grade

  • Molecular subtypes (especially TNBC vs. non-TNBC)

In research by Zhu et al., PPP1R14C expression was evaluated using IHC in 150 breast cancer specimens (50 non-TNBCs and 100 TNBCs), showing significantly higher expression in TNBC compared to normal and non-TNBC tissues .

How does PPP1R14C function in the regulation of GSK3β signaling in cancer?

PPP1R14C regulates GSK3β through a sophisticated dual mechanism:

• Inhibition of PP1-mediated dephosphorylation:

  • PPP1R14C binds to PP1 through its RVXF motif

  • When phosphorylated at Thr73 by PRKCI, PPP1R14C becomes a potent inhibitor of PP1

  • This inhibition prevents PP1 from dephosphorylating GSK3β at Ser9

  • Increased p-GSK3β-Ser9 levels result in GSK3β inactivation

• Promotion of GSK3β protein degradation:

  • Phosphorylated PPP1R14C (p-PPP1R14C) recruits E3 ligase TRIM25

  • TRIM25 promotes ubiquitylation and degradation of non-phosphorylated GSK3β

  • This further reduces active GSK3β levels in the cell

These mechanisms form a p-PPP1R14C/PP1/p-GSK3β-Ser9 complex that maintains GSK3β in an inactive state, promoting cancer cell proliferation, invasion, and metastasis .

The pathway is supported by co-immunoprecipitation experiments demonstrating direct interactions between PPP1R14C, PP1, and GSK3β in TNBC cells .

What experimental approaches can detect PPP1R14C-PP1-GSK3β interactions?

To investigate PPP1R14C-PP1-GSK3β interactions, researchers should employ:

• Co-immunoprecipitation (Co-IP) assays:

  • Immunoprecipitate with anti-PPP1R14C antibodies and blot for PP1 and p-GSK3β-Ser9

  • Reverse Co-IP with anti-PP1 antibodies and blot for PPP1R14C and p-GSK3β-Ser9

  • Use mutant PPP1R14C constructs (RVXF deletion or T73A mutation) as negative controls

• Proximity ligation assays (PLA):

  • For detecting in situ protein-protein interactions in fixed cells/tissues

  • Use antibody pairs targeting PPP1R14C and PP1 or PPP1R14C and GSK3β

• In vitro phosphatase assays:

  • Measure PP1 activity using phosphorylated substrates in the presence/absence of PPP1R14C

  • Test effects of PPP1R14C phosphorylation status on PP1 inhibition

• GST pull-down assays:

  • Using recombinant GST-tagged PPP1R14C to identify direct binding partners

  • Compare wild-type and mutant PPP1R14C proteins

Research by Zhu et al. demonstrated that PPP1R14C forms a complex with PP1 and p-GSK3β-Ser9 in TNBC cells, and that phosphorylation at Thr73 is essential for PPP1R14C's inhibitory effect on PP1 .

What are the effects of PPP1R14C phosphorylation on its function and detection?

PPP1R14C phosphorylation, particularly at Threonine 73 (Thr73), critically affects both its function and detection:

Functional effects:

• Phosphorylation at Thr73 by PRKCI converts PPP1R14C into a potent inhibitor of PP1

• Phosphorylated PPP1R14C (p-PPP1R14C) maintains GSK3β in an inactive state by:

  • Preventing PP1-mediated dephosphorylation of p-GSK3β-Ser9

  • Recruiting E3 ligase TRIM25 to degrade non-phosphorylated GSK3β

• T73A mutation abolishes PPP1R14C's ability to inhibit PP1 and restore p-GSK3β-Ser9 levels

Detection considerations:

• For phospho-specific detection:

  • Phospho-specific antibodies against p-PPP1R14C-Thr73 are required

  • Sample preparation must include phosphatase inhibitors

  • Alkaline phosphatase treatment can serve as a negative control

• For total PPP1R14C detection:

  • Antibodies recognizing PPP1R14C regardless of phosphorylation status should be used

  • Multiple bands may appear due to post-translational modifications

Research has shown that PRKCI-mediated phosphorylation of PPP1R14C at Thr73 is essential for its oncogenic function in TNBC, making this phosphorylation site a potential therapeutic target .

How should researchers interpret PPP1R14C expression data in different breast cancer subtypes?

Interpreting PPP1R14C expression across breast cancer subtypes requires careful analysis:

What are the current limitations in PPP1R14C antibody research and how can they be addressed?

Current limitations in PPP1R14C antibody research include:

• Antibody specificity issues:

  • Limited validation across multiple techniques

  • Potential cross-reactivity with related family members (PPP1R14A, PPP1R14B, PPP1R14D)

  • Solution: Validate using knockout/knockdown controls and peptide competition assays

• Phospho-specific detection challenges:

  • Few validated phospho-specific antibodies against p-PPP1R14C-Thr73

  • Phosphorylation state may be lost during sample processing

  • Solution: Develop well-characterized phospho-specific antibodies and optimize sample preservation

• Inconsistent detection across species:

  • Variable cross-reactivity between human, mouse, and rat PPP1R14C

  • Solution: Validate species reactivity experimentally and use species-specific positive controls

• Technical challenges in low-abundance detection:

  • PPP1R14C may be expressed at low levels in some tissues

  • Solution: Employ signal amplification methods and optimize extraction protocols

• Standardization issues:

  • Varied protocols across studies limit comparability

  • Solution: Establish standardized protocols for PPP1R14C detection across applications

Researchers should address these limitations through rigorous antibody validation, including knockout controls, multiple detection methods, and careful optimization of experimental conditions.

How might PPP1R14C research inform therapeutic approaches for triple-negative breast cancer?

PPP1R14C research reveals several potential therapeutic approaches for TNBC:

• Direct targeting of PPP1R14C:

  • Inhibitors of PPP1R14C expression or function

  • CRISPR/Cas9-mediated disruption of PPP1R14C in preclinical models

  • Small molecules that prevent PPP1R14C-PP1 interaction

• Targeting PPP1R14C phosphorylation:

  • PRKCI inhibitors to prevent Thr73 phosphorylation

  • Blockade of PPP1R14C phosphorylation inhibited xenograft tumorigenesis and lung metastasis of TNBC cells

• Targeting downstream pathways:

  • GSK3β activation strategies

  • C2 ceramide (C2), a PP1 activator, reversed PPP1R14C-induced malignant phenotypes

  • Combination approaches targeting both PPP1R14C and GSK3β pathways

• Biomarker potential:

  • High PPP1R14C expression predicts poor prognosis in TNBC

  • PPP1R14C could identify aggressive TNBC subtypes requiring intensive therapy

  • PPP1R14C status might predict response to GSK3β-targeting therapies

Research by Zhu et al. demonstrated that C2 ceramide treatment reversed the malignant phenotype induced by PPP1R14C, suggesting a potential novel therapeutic strategy for TNBC . Additionally, blockade of PPP1R14C phosphorylation showed anti-cancer activity in preclinical models .

What are emerging applications of PPP1R14C antibodies in cancer research beyond breast cancer?

While PPP1R14C has been primarily studied in TNBC, emerging research suggests broader applications:

• Expanding cancer type investigations:

  • Related PP1 inhibitor PPP1R14D is implicated in lung adenocarcinoma (LUAD)

  • PPP1R14C may have roles in other cancers with dysregulated GSK3β signaling

  • Systematic screening across cancer types using tissue microarrays and PPP1R14C antibodies

• Single-cell analysis applications:

  • PPP1R14C antibodies in single-cell proteomics

  • Spatial transcriptomics combined with IHC to map PPP1R14C expression in tumor microenvironments

  • Correlation with cancer stem cell markers

• Liquid biopsy development:

  • Detection of circulating tumor cells expressing PPP1R14C

  • Correlation with metastatic potential and treatment response

• Drug screening platforms:

  • High-content screening using PPP1R14C antibodies to identify compounds that modulate its expression or activity

  • Development of reporter cell lines for PPP1R14C activity

Research on related PP1 regulatory proteins suggests PPP1R14C may have roles in multiple cancer types, warranting broader investigation beyond TNBC .

How can advanced microscopy techniques enhance PPP1R14C research using antibodies?

Advanced microscopy techniques can revolutionize PPP1R14C research through:

• Super-resolution microscopy:

  • STED, PALM, or STORM imaging to visualize PPP1R14C subcellular localization at nanoscale resolution

  • Co-localization with PP1 and GSK3β at previously undetectable resolution

  • Tracking dynamic changes in PPP1R14C distribution during cell cycle or in response to stimuli

• Live-cell imaging approaches:

  • Using fluorescently-tagged nanobodies against PPP1R14C for live-cell dynamics

  • FRET/FLIM imaging to detect PPP1R14C-PP1 interactions in real-time

  • Photoactivatable or photoconvertible fluorescent protein fusions to track protein movement

• Correlative light and electron microscopy (CLEM):

  • Precise ultrastructural localization of PPP1R14C using immunogold labeling

  • Visualization of PPP1R14C in specialized membrane domains

• Multiplexed imaging:

  • Cyclic immunofluorescence (CycIF) or CO-Detection by indEXing (CODEX) for simultaneous detection of multiple proteins in the PPP1R14C pathway

  • Mass cytometry imaging to quantify PPP1R14C and associated pathway components in tissue sections

These techniques would provide unprecedented insights into the spatial organization and dynamic regulation of PPP1R14C in cancer cells.

What methodological approaches can help resolve contradictory findings about PPP1R14C in cancer research?

To address contradictory findings about PPP1R14C in cancer research:

• Standardized reporting and methodology:

  • Detailed reporting of antibody validation methods, catalog numbers, and dilutions

  • Standardized protocols for tissue processing and staining

  • Consistent scoring systems for expression analysis

• Multi-omics integration:

  • Correlate protein expression (using antibodies) with transcriptomic data

  • Integrate phosphoproteomic data to assess functional state

  • Meta-analysis across multiple datasets with consistent methodology

• Context-specific analysis:

  • Evaluate PPP1R14C in specific molecular subtypes rather than broadly across cancer types

  • Consider tumor heterogeneity through single-cell approaches

  • Assess microenvironmental influences on PPP1R14C expression

• Functional validation:

  • Genetic manipulation (overexpression, knockdown, mutation) to confirm causality

  • Rescue experiments to verify specificity of observed phenotypes

  • In vivo validation using genetically engineered mouse models

Research should address contradictions between earlier studies suggesting PPP1R14C downregulation in breast cancer and more recent findings showing upregulation in TNBC specifically, highlighting the importance of subtype-specific analysis .