QCR2 Antibody

What is QCR2 and what are the optimal applications for QCR2 antibodies?

QCR2 (UQCRC2) is a core component of the mitochondrial respiratory chain complex III, formally known as ubiquinol-cytochrome c reductase core protein II. This 48 kDa protein is essential for mitochondrial function and cellular energy production.

QCR2 antibodies, such as the 14742-1-AP, can be utilized in multiple experimental applications:

For optimal results in IHC applications, antigen retrieval with TE buffer pH 9.0 is suggested, though citrate buffer pH 6.0 may serve as an alternative .

How should I validate QCR2 antibody specificity for my experimental system?

Validating antibody specificity is critical for reliable research outcomes. For QCR2 antibody validation:

• Positive Controls: Use tissues/cells known to express QCR2 (heart, brain, colon tissues)

• Knockdown/Knockout Validation: Employ siRNA knockdown or CRISPR knockout systems targeting QCR2 and verify signal reduction/elimination

• Western Blot Analysis: Confirm a single band at the expected molecular weight (48 kDa)

• Cross-Species Reactivity: The 14742-1-AP antibody shows reactivity with human, mouse, and rat samples, with cited reactivity in zebrafish and sheep

• Immunogen Analysis: Check if the immunogen sequence used to generate the antibody (UQCRC2 fusion protein Ag6432) aligns with your species of interest

Published literature has utilized QCR2 antibodies in various contexts, with 77 publications employing WB, 3 using IHC, and 3 reporting IF applications, providing additional validation support .

What are the recommended storage and handling conditions for QCR2 antibodies?

For optimal stability and performance of QCR2 antibodies:

• Store at -20°C where they remain stable for one year after shipment

• The antibody is provided in PBS with 0.02% sodium azide and 50% glycerol at pH 7.3

• Aliquoting is unnecessary for -20°C storage

• Note that small volume formats (20μl) contain 0.1% BSA

• Avoid repeated freeze-thaw cycles which can degrade antibody quality and performance

How can I investigate QCR2's role in p53 regulation using QCR2 antibodies?

Recent research has revealed that QCR2 functions as a negative regulator of p53, promoting tumorigenesis. To investigate this relationship:

• Co-immunoprecipitation (Co-IP): Use QCR2 antibodies (0.5-4.0 μg for 1.0-3.0 mg of total protein lysate) to pull down QCR2 and associated proteins, then probe for p53 and PHB (Prohibitin)

• Subcellular Localization Studies: Employ immunofluorescence with QCR2 antibodies (1:50-1:500 dilution) alongside mitochondrial markers and nuclear markers to track QCR2 localization

• Ubiquitination Assays: Following QCR2 overexpression or knockdown, immunoprecipitate p53 and probe for ubiquitin to assess QCR2's impact on p53 ubiquitination

• Downstream Pathway Analysis: After QCR2 manipulation, use antibodies against p21 and other p53 target genes to monitor pathway activation

Research has shown that QCR2 suppression inhibits cancer cell growth by activating p53 signaling and inducing p21-dependent cell cycle arrest and senescence. QCR2 directly interacts with PHB in the mitochondria and can inhibit PHB binding to p53 in the nucleus, facilitating p53 ubiquitination and degradation .

What methodological considerations are important when studying QCR2 in cancer models?

When investigating QCR2 in cancer:

• Expression Analysis: QCR2 is upregulated in multiple human tumors, including cervical cancer, lung adenocarcinoma, and breast cancer

• Functional Assays:

  • Proliferation: CCK-8 assay and EdU staining following QCR2 knockdown

  • Cell Cycle Analysis: Flow cytometry after QCR2 manipulation

  • Senescence: β-galactosidase staining following QCR2 suppression

• Protein Interaction Studies:

  • QCR2 interacts with PHB in mitochondria

  • QCR2 influences PHB-p53 interaction in the nucleus

  • Mass spectrometry following QCR2 immunoprecipitation can identify novel interacting partners

• Clinical Correlation:

  • Analyze QCR2, PHB, and p21 expression levels in patient samples

  • Increased QCR2 and decreased PHB protein levels correlate with decreased p21 expression in cervical cancer tissues

How can QCR2 antibodies be utilized in mitochondrial function studies?

QCR2 antibodies provide valuable tools for investigating mitochondrial function:

• Respiratory Complex Assembly: Use QCR2 antibodies in blue native PAGE to assess complex III assembly

• Mitochondrial Import Mechanisms: Study the efficacy of mitochondrial targeting sequences by tracking QCR2 localization with immunofluorescence

• Allotopic Expression Studies: Antibodies can confirm successful expression of nuclear-encoded QCR2 targeted to mitochondria in studies exploring mitochondrial disease therapies

Recent research has utilized QCR2's mitochondrial targeting sequence in allotopic expression systems. The QCR2 MTS has been employed in genetic engineering approaches using YeastFab assembly to build expression vectors for optimizing allotopic expression conditions .

What are the critical steps for successful Western blotting of QCR2?

For optimal Western blotting results with QCR2 antibodies:

• Sample Preparation:

  • Extract proteins using RIPA buffer supplemented with protease inhibitors

  • Load approximately 60 μg of whole cell lysate

• Gel Electrophoresis and Transfer:

  • Use 10-12% acrylamide gels for optimal separation of the 48 kDa QCR2 protein

  • Transfer to PVDF membranes at 100V for 60-90 minutes or 30V overnight at 4°C

• Antibody Incubation:

  • Primary antibody (14742-1-AP): Use at 1:2000-1:12000 dilution, incubate at 4°C overnight

  • Secondary antibody options: IRDye 800CW goat anti-rabbit IgG or HRP-conjugated goat anti-rabbit IgG

• Detection:

  • For fluorescent detection: Use Odyssey scanner (LI-COR)

  • For chemiluminescence: Use ECL detection reagents

• Troubleshooting:

  • Multiple bands: Optimize antibody dilution or consider pre-absorbing the antibody

  • Weak signal: Increase protein loading or antibody concentration

  • High background: Increase washing steps or blocking time

How can I optimize immunofluorescence staining with QCR2 antibody for subcellular localization studies?

For precise subcellular localization of QCR2:

• Fixation and Permeabilization:

  • For mitochondrial proteins, 4% paraformaldehyde fixation for 15 minutes followed by 0.2% Triton X-100 permeabilization for 10 minutes is recommended

  • Alternative: Cold methanol fixation for 5 minutes at -20°C

• Blocking and Antibody Dilution:

  • Block with 3-5% BSA in PBS for 1 hour at room temperature

  • Use QCR2 antibody at 1:50-1:500 dilution in blocking buffer

• Co-staining for Organelle Visualization:

  • For mitochondria: Use MitoTracker or antibodies against other mitochondrial markers

  • For nuclear co-localization studies: Include DAPI or Hoechst nuclear stains

• Confocal Microscopy Settings:

  • Use appropriate laser settings to minimize bleed-through

  • Consider super-resolution microscopy for detailed mitochondrial morphology

• Controls:

  • Include QCR2 knockdown cells as negative controls

  • Use cells with known QCR2 overexpression as positive controls

Validated cell lines for QCR2 immunofluorescence include HepG2 cells, which consistently show positive staining .

How should I interpret conflicting results between QCR2 protein levels and mRNA expression?

When facing discrepancies between QCR2 protein and mRNA levels:

• Post-translational Modifications: Investigate potential ubiquitination, phosphorylation, or other modifications affecting protein stability

• Protein-Protein Interactions: Consider whether PHB or other interacting partners influence QCR2 stability or detection

• Methodological Approach:

  • For protein analysis: Use Western blotting with 14742-1-AP antibody at 1:2000-1:12000 dilution

  • For mRNA analysis: Extract total RNA using TRIzol reagent and perform RT-qPCR with appropriate primers

• Transcriptional vs. Post-transcriptional Regulation:

  • Analyze microarray data to identify potential regulatory mechanisms

  • Consider RNA-binding proteins or miRNAs that might influence QCR2 mRNA stability

• Cell Type Specificity:

  • Different tissues may exhibit varying relationships between QCR2 mRNA and protein levels

  • Compare results across different cell types when possible

What considerations are important when analyzing QCR2's dual role in mitochondrial function and p53 regulation?

To properly interpret QCR2's dual functionality:

• Compartment-Specific Analysis:

  • Use subcellular fractionation to separate mitochondrial and nuclear pools of QCR2

  • Perform immunoprecipitation experiments in each fraction to identify compartment-specific interacting partners

• Temporal Dynamics:

  • Consider timing of QCR2 translocation between compartments

  • Use time-course experiments following cellular stress to track QCR2 localization changes

• Functional Separation:

  • Design experiments to distinguish between respiratory chain functions and p53 regulatory roles

  • Use respiratory chain inhibitors to differentiate direct and indirect effects on p53 pathway

• Mutation Analysis:

  • Consider engineered QCR2 variants that selectively disrupt either mitochondrial function or p53 interaction

  • Use the QCR2-PHB interaction interface as a target for such mutations

• Integrated Analysis:

  • Correlate mitochondrial respiratory function with p53 activity following QCR2 manipulation

  • Consider whether metabolic changes resulting from altered QCR2 function indirectly affect p53

What are emerging applications of QCR2 antibodies in therapeutic target validation?

QCR2 represents a promising therapeutic target given its role in tumorigenesis and p53 regulation:

• Target Validation:

  • QCR2 antibodies can help validate the efficacy of small molecule inhibitors targeting QCR2

  • Use in immunoprecipitation (0.5-4.0 μg for 1.0-3.0 mg of protein) to confirm target engagement

• Biomarker Development:

  • QCR2 overexpression correlates with tumorigenesis in multiple cancers

  • QCR2/PHB/p53 axis provides potential prognostic indicators

• Precision Medicine Applications:

  • QCR2 antibodies can help stratify patient samples based on expression levels

  • May identify patients likely to respond to therapies targeting mitochondrial function

• Combination Therapy Assessment:

  • Evaluate the effects of combining QCR2-targeting approaches with conventional cancer therapies

  • Monitor changes in QCR2 expression and localization following treatment

Current evidence highlights QCR2 as a negative regulator of p53, suggesting its potential as an anti-cancer target. Further exploration of the QCR2-PHB-p53 regulatory network may yield novel therapeutic approaches for cancers expressing wild-type p53 .

How might QCR2 antibodies contribute to understanding mitochondrial disease mechanisms?

QCR2 antibodies offer valuable tools for investigating mitochondrial diseases:

• Respiratory Chain Defects:

  • Use QCR2 antibodies to assess complex III assembly and function in patient samples

  • Correlate QCR2 expression with clinical phenotypes in mitochondrial myopathies

• Allotopic Expression Studies:

  • QCR2 antibodies can verify successful mitochondrial targeting in gene therapy approaches

  • Monitor expression and integration of nuclear-encoded mitochondrial proteins

• Mitochondrial-Nuclear Communication:

  • Investigate QCR2's role in retrograde signaling from mitochondria to nucleus

  • Track QCR2 involvement in stress responses and mitochondrial quality control

• Therapeutic Development:

  • Evaluate QCR2 as a target for improving mitochondrial function in disease states

  • Monitor therapeutic efficacy through changes in QCR2 expression and localization

Recent engineering biology approaches using QCR2's mitochondrial targeting sequence demonstrate the potential for optimizing allotopic expression of mitochondrial proteins, which could prove valuable for developing therapies for mitochondrial diseases .