CNTROB Antibody

What is CNTROB and why is it an important research target?

CNTROB (centrobin, centrosomal BRCA2 interacting protein) is a 903-amino acid protein with a calculated molecular weight of 101 kDa, though observed molecular weights can range from 60-130 kDa depending on the detection method . It plays crucial roles in centriole duplication and primary ciliogenesis in vertebrates . CNTROB is particularly important for researchers studying centrosome regulation, cilia formation, and potentially associated human diseases such as microcephaly and ciliopathies .

Methodologically, researchers should consider both the full-length protein and its functional domains when designing experiments, as the C-terminal region (residues 452-903) has been shown to interact with CP110, a key negative regulator of ciliogenesis .

Which cell lines and tissue samples are most suitable for CNTROB antibody validation?

Based on current literature, the following systems are recommended for CNTROB antibody validation:

Cell lines:

• hTERT-RPE1 cells (human retinal pigmented epithelial cells) - extensively used and validated for CNTROB localization studies

• A549 cells (human lung adenocarcinoma cells)

• HCT116 (human colorectal carcinoma)

Tissue samples:

• Brain tissue (mouse, rat, pig) has shown reliable detection of CNTROB

• Multiple human cell lines including NCI-H1299, JAR, Jurkat, and K-562 cells have demonstrated positive Western blot detection

When validating a new CNTROB antibody, researchers should include both positive controls using these recommended samples and negative controls using CNTROB knockout cell lines, such as those generated through CRISPR-Cas9 genome editing in hTERT-RPE1 cells .

What are the optimal dilutions for different applications of CNTROB antibodies?

The recommended dilutions vary by antibody clone and application:

It is crucial to optimize these dilutions for each specific experimental system, as the manufacturer notes: "It is recommended that this reagent should be titrated in each testing system to obtain optimal results" .

How should CNTROB antibodies be stored and handled for maximum stability?

For optimal performance and longevity of CNTROB antibodies, follow these storage and handling guidelines:

How can I distinguish between different isoforms or post-translational modifications of CNTROB in my experiments?

CNTROB can be detected at different molecular weights (60-70 kDa, 97 kDa, or 100-130 kDa) depending on the antibody and experimental conditions . This variability may reflect different isoforms, post-translational modifications, or proteolytic processing.

To distinguish between these possibilities:

• Epitope mapping: Use antibodies targeting different epitopes. For example, Proteintech's polyclonal antibody (26880-1-AP) recognizes an immunogen sequence different from Boster's antibody (A08210-1) which targets amino acids 591-640 .

• Knockout validation: Generate CNTROB knockout cells as negative controls. Previous studies have used genome editing to ablate CNTROB in hTERT-RPE1 cells, confirming the specificity of antibody detection .

• Domain-specific antibodies: Consider using antibodies that recognize specific domains. Research has shown that the N-terminal (1-364) and C-terminal (365-903) domains of CNTROB have distinct functions and interaction partners .

• Immunoprecipitation followed by mass spectrometry: To identify post-translational modifications, perform immunoprecipitation of CNTROB followed by mass spectrometry analysis. The coimmunoprecipitation protocol detailed in the literature can be adapted for this purpose .

• Phosphatase treatment: Since many centrosomal proteins are regulated by phosphorylation, treating cell lysates with phosphatase prior to Western blotting can help determine if multiple bands represent phosphorylated forms.

What experimental approaches can address the apparent discrepancy between CNTROB's calculated (101 kDa) and observed molecular weights (60-130 kDa)?

The discrepancy between CNTROB's calculated molecular weight (101 kDa, 903 amino acids) and its observed weights in various experimental settings (60-70 kDa, 97 kDa, or 100-130 kDa) represents a common challenge in protein research. To address this discrepancy:

• Sequential immunoblotting: Probe the same membrane with multiple CNTROB antibodies recognizing different epitopes to determine if all isoforms/fragments are detected by each antibody.

• Domain-specific antibodies: Use antibodies that target specific regions (N-terminal vs. C-terminal) to identify which portions of the protein are present in different molecular weight bands.

• Expression of truncated constructs: Express defined fragments of CNTROB (e.g., 1-364, 365-903, 452-903) as positive controls to map the sizes of potential fragmentation products .

• 2D gel electrophoresis: Combine isoelectric focusing with SDS-PAGE to separate proteins based on both charge and size, potentially resolving different post-translationally modified forms.

• Cell-cycle synchronization: Since centrosomal proteins often undergo cell cycle-dependent modifications, analyze CNTROB in synchronized cells to determine if the molecular weight varies throughout the cell cycle.

• Mass spectrometry: Immunoprecipitate CNTROB and analyze by mass spectrometry to determine the exact composition of different molecular weight species.

How can I establish a reliable system to study CNTROB's role in ciliogenesis and its interaction with CP110?

CNTROB plays a critical role in primary ciliogenesis through its interaction with CP110, a key negative regulator of ciliogenesis . To establish a robust experimental system:

• Cell model selection: Use hTERT-RPE1 cells, which form primary cilia upon serum starvation and have been extensively characterized for CNTROB function .

• CNTROB knockout/rescue system: Generate CNTROB knockout cells using CRISPR-Cas9 genome editing and create stable rescue lines expressing full-length CNTROB or specific domains (like the 452-903 fragment that permits ciliogenesis) .

• Ciliogenesis induction protocol:

  • Grow cells to 70-80% confluence

  • Wash cells with PBS

  • Culture in serum-free medium for 24-48 hours

  • Assess ciliation by immunofluorescence using acetylated tubulin or ARL13B antibodies to mark cilia

• CP110-CNTROB interaction studies:

  • Coimmunoprecipitation using C-terminal CNTROB (365-903) constructs

  • Immunofluorescence to monitor CP110 removal from the distal end of the mother centriole during ciliogenesis

  • CP110 knockdown in CNTROB-null cells to test rescue of ciliogenesis

• Functional readouts:

  • Percentage of ciliated cells

  • Cilia length measurements

  • Localization of ciliary proteins

  • CP110 localization at the distal end of centrioles

This system allows for detailed mechanistic studies of how CNTROB contributes to ciliogenesis through both microtubule stabilization and CP110 regulation .

What are the optimal controls for CNTROB antibody specificity validation in different applications?

Rigorous validation of CNTROB antibody specificity requires appropriate controls for each application:

For Western Blot:

• Positive control tissues/cells: Mouse brain tissue, hTERT-RPE1 cells, A549 cells

• Negative controls:

  • CNTROB knockout cells generated by CRISPR-Cas9

  • siRNA knockdown samples

• Recombinant protein controls: Expression of tagged CNTROB fragments (full-length, N-terminal, C-terminal)

• Loading controls: Standard housekeeping proteins like GAPDH

For Immunofluorescence/ICC:

• Positive control cell line: hTERT-RPE1 cells, which show centrosomal localization of CNTROB

• Negative controls:

  • CNTROB knockout or knockdown cells

  • Primary antibody omission

  • Non-specific IgG from the same species as the primary antibody

• Co-staining controls: Co-stain with established centrosomal markers (e.g., ɣ-tubulin, CP110)

For Immunohistochemistry:

• Positive control tissues: Brain tissue samples

• Negative controls:

  • Primary antibody omission

  • Blocking peptide competition

  • Non-specific IgG controls

For Coimmunoprecipitation:

• Input controls: Total cell lysate before immunoprecipitation

• Negative controls:

  • IgG from the same species as the immunoprecipitating antibody

  • Lysate from CNTROB knockout cells

• Reciprocal IP: Confirm interactions by immunoprecipitating the suspected binding partner (e.g., CP110) and blotting for CNTROB

What are the potential implications of CNTROB dysfunction in human disease, and how can antibodies help investigate these connections?

CNTROB dysfunction has been linked to several potential disease mechanisms, particularly those involving centrosome regulation and cilia formation :

• Microcephaly and primordial dwarfism:

  • CNTROB interacts with CPAP/CENPJ, a known microcephaly gene

  • Its role in centriole duplication links it to primary microcephaly pathways

  • Research approach: Use CNTROB antibodies to assess protein levels and localization in patient-derived cells or animal models of microcephaly

• Ciliopathies:

  • CNTROB knockout in cells impairs primary ciliogenesis

  • Rat hypodactyly mutants with truncating CNTROB mutations show skeletal abnormalities and male infertility due to defective sperm flagellar axoneme assembly

  • Research approach: Immunofluorescence studies of primary cilia formation in relevant tissues; analysis of ciliary signaling pathways

• Cancer:

  • Centrosomal abnormalities are common in cancer

  • Research approach: Tissue microarray analysis using CNTROB antibodies to assess expression in tumor samples versus normal tissues

• Experimental strategies:

  • Patient-derived cell studies: Compare CNTROB localization, expression, and interaction partners in cells from patients with suspected ciliopathies or microcephaly

  • Animal models: Use CNTROB antibodies to characterize phenotypes in zebrafish morphants or mouse models

  • Functional studies: Assess the impact of disease-associated CNTROB variants on centriole duplication and ciliogenesis

• Technical considerations:

  • Use multiple antibodies targeting different epitopes to ensure comprehensive detection

  • Include proper controls (tissue-matched normal samples)

  • Combine with genetic analyses to correlate phenotypes with specific mutations

This research direction remains largely unexplored, as the paper notes: "A human disease role for centrobin remains to be determined" .

What are the most effective protein extraction methods for detecting CNTROB in Western blotting?

For optimal CNTROB detection in Western blotting, consider the following extraction protocol based on published methodologies :

• Cell harvesting: Trypsinize cells (e.g., hTERT-RPE1, HCT116) and collect by centrifugation.

• Lysis buffer composition:

  • 50 mM Tris HCl, pH 7.4

  • 150 mM NaCl

  • 20% glycerol

  • 1 mM EDTA

  • 0.5% sodium deoxycholate

  • 1% IGEPAL (NP-40)

  • Protease inhibitor cocktail (Roche)

  • 1 mM sodium orthovanadate

  • 5 mM sodium fluoride

  • 1:10,000 dilution of benzonase nuclease

  • 1 mM PMSF

• Lysis procedure:

  • Incubate cells in lysis buffer for 45 minutes at 4°C on a rotating wheel

  • Centrifuge for 20 minutes at 18,000 g at 4°C

  • Transfer supernatant to a fresh tube

• Protein quantification:

  • Determine concentration by Bradford assay

  • Use 20-50 μg of total protein per lane for SDS-PAGE

• Sample preparation:

  • Mix with 5× Laemmli buffer

  • Heat at 95°C for 10 minutes before loading

• Gel selection:

  • Use 8% or 7.5% gels to better resolve high molecular weight proteins

  • Consider gradient gels (4-15%) to simultaneously visualize different molecular weight forms

• Transfer conditions:

  • For high molecular weight forms (100-130 kDa), extend transfer time or use wet transfer systems

  • Consider using PVDF membranes instead of nitrocellulose for better protein retention

• Blocking and antibody incubation:

  • Follow manufacturer's recommendations for specific antibodies

  • For monoclonal 67061-1-Ig: 1:5000-1:50000 dilution

  • For polyclonal 26880-1-AP: 1:500-1:1000 dilution

How can I optimize immunofluorescence protocols for detecting CNTROB at centrosomes?

For high-quality immunofluorescence detection of CNTROB at centrosomes, consider the following optimized protocol:

• Cell preparation:

  • Grow cells on coverslips to 60-70% confluence

  • For optimal centrosome visualization, use hTERT-RPE1 cells, which have been extensively validated

• Fixation options:

  • Method 1: 4% paraformaldehyde (PFA) for 10 minutes at room temperature

  • Method 2: Ice-cold methanol for 5 minutes at -20°C (better for preserving centrosomal structures)

  • Method 3: For optimal centrosome preservation, pre-extract with 0.5% Triton X-100 in PHEM buffer (60 mM PIPES, 25 mM HEPES, 10 mM EGTA, 2 mM MgCl2, pH 6.9) for 30 seconds before methanol fixation

• Permeabilization:

  • If using PFA fixation, permeabilize with 0.1-0.5% Triton X-100 in PBS for 5-10 minutes

  • No additional permeabilization needed for methanol fixation

• Blocking:

  • 3-5% BSA or normal serum (goat or donkey) in PBS for 30-60 minutes at room temperature

• Primary antibody incubation:

  • For polyclonal antibody 26880-1-AP: dilute 1:50-1:500 in blocking solution

  • For monoclonal antibody 67061-1-Ig: dilute 1:175-1:700 in blocking solution

  • Incubate overnight at 4°C or 1-2 hours at room temperature

• Co-staining markers:

  • Include a centrosome marker like γ-tubulin for colocalization studies

  • For ciliogenesis studies, include acetylated tubulin or ARL13B to mark primary cilia

• Secondary antibody incubation:

  • Use appropriate species-specific secondary antibodies (e.g., goat anti-rabbit or goat anti-mouse)

  • Dilute 1:500-1:1000 in blocking solution

  • Incubate for 1 hour at room temperature

  • Include DAPI (1:1000) for nuclear counterstaining

• Mounting:

  • Use anti-fade mounting medium to preserve fluorescence

• Imaging considerations:

  • Confocal microscopy is recommended for precise localization

  • Z-stack imaging to capture the entire centrosome structure

  • Use high magnification (63× or 100× objectives) with oil immersion

• Controls:

  • Include CNTROB knockout cells as negative controls

  • Use primary antibody omission and non-specific IgG controls

What troubleshooting strategies should I employ when CNTROB antibodies show inconsistent results?

When facing inconsistent results with CNTROB antibodies, consider these systematic troubleshooting approaches:

For Western Blot inconsistencies:

• Multiple bands or unexpected molecular weights:

  • Normal observation: CNTROB can appear at 60-70 kDa, 97 kDa, or 100-130 kDa

  • Solution: Use CNTROB knockout cells or siRNA knockdown samples as negative controls

  • Try different extraction buffers to preserve protein integrity

  • Check for proteolytic degradation by adding additional protease inhibitors

• Weak or no signal:

  • Increase protein loading (50-100 μg)

  • Try longer exposure times

  • Reduce washing stringency

  • Test alternative antibody concentrations:

    • For monoclonal (67061-1-Ig): Try higher concentration within 1:5000-1:50000 range

    • For polyclonal (26880-1-AP): Try 1:250 if 1:500-1:1000 doesn't work

  • Try different detection systems (ECL vs. fluorescent)

• High background:

  • Increase blocking time or concentration

  • Use alternative blocking agents (milk vs. BSA)

  • Increase washing steps and duration

  • Dilute antibody further

For Immunofluorescence inconsistencies:

• No centrosomal signal:

  • Try both methanol and PFA fixation methods

  • Add pre-extraction step to remove cytoplasmic proteins

  • Increase antibody concentration

  • Extend primary antibody incubation time

  • Co-stain with γ-tubulin to confirm centrosome visualization

• Non-specific staining:

  • Increase blocking time

  • Use alternative blocking agents

  • Dilute antibody further

  • Include detergent in antibody dilution buffer

  • Compare patterns with published images of CNTROB localization

• Cell type-specific issues:

  • CNTROB detection works best in hTERT-RPE1 cells

  • For other cell types, optimize fixation and permeabilization conditions

  • Consider cell cycle stage (CNTROB localization may vary)

General validation approaches:

• Cross-validation with multiple antibodies:

  • Compare results using both polyclonal and monoclonal antibodies

  • Test antibodies recognizing different epitopes

• Genetic validation:

  • Use CRISPR-Cas9 to generate CNTROB knockout cells as negative controls

  • Perform rescue experiments with exogenous CNTROB expression

• Batch-to-batch variability:

  • Request validation data from manufacturer for specific lot

  • Establish internal positive controls for each new antibody batch

  • Consider alternative suppliers if consistent issues persist

What are the most informative experimental designs for studying CNTROB's role in centriole duplication?

To comprehensively investigate CNTROB's function in centriole duplication, consider these experimental approaches:

• Genetic manipulation systems:

  • CRISPR-Cas9 knockout in hTERT-RPE1 cells (complete ablation)

  • siRNA/shRNA knockdown (acute depletion)

  • Inducible degron-tagged CNTROB (temporal control)

  • Rescue experiments with full-length and truncated constructs

• Cell cycle synchronization studies:

  • Synchronize cells at G1/S boundary using double thymidine block

  • Release and collect timepoints throughout S phase

  • Quantify centrosome numbers using γ-tubulin or centrin staining

  • Monitor CNTROB localization throughout the cell cycle

• Interaction studies with centriole duplication machinery:

  • Coimmunoprecipitation with known regulators (CPAP/CENPJ, PLK4, SAS-6)

  • Proximity labeling approaches (BioID, APEX)

  • Live cell imaging with fluorescently tagged proteins

• Functional readouts:

  • Quantification of acentriolar and monocentriolar cells

  • Cell proliferation analysis

  • Cell cycle profile analysis by flow cytometry

  • Mitotic spindle formation assessment

• Domain analysis:

  • Express individual domains of CNTROB (N-terminal 1-364, C-terminal 365-903)

  • Assess their localization and functionality

  • Perform structure-function analyses with point mutations

• Model systems beyond cell culture:

  • Mouse models with conditional Cntrob knockout

  • Zebrafish morpholino knockdown

  • Drosophila genetic studies

• Advanced imaging approaches:

  • Super-resolution microscopy (STORM, PALM, SIM)

  • Correlative light and electron microscopy

  • Live cell imaging of centriole duplication

These approaches can be combined with antibody-based detection methods to provide comprehensive insights into CNTROB's mechanistic role in centriole duplication .

How can CNTROB antibodies be effectively used to investigate potential links between centrosome dysfunction and human diseases?

CNTROB antibodies can serve as valuable tools for investigating the relationship between centrosome dysfunction and human diseases:

• Clinical sample analysis:

  • Tissue microarrays: Screen multiple patient samples using immunohistochemistry with CNTROB antibodies

  • Patient-derived cells: Compare CNTROB expression, localization, and modification in cells from patients with microcephaly, primordial dwarfism, or ciliopathies

  • Control tissues: Use normal adjacent tissue or age-matched controls

• Disease model characterization:

  • Animal models: Analyze CNTROB expression in rodent models of microcephaly or ciliopathies

  • Organoid systems: Study centrosome dynamics in brain organoids derived from patient iPSCs

  • Zebrafish: Examine phenotypes in zebrafish embryos with cntrob knockdown

• Specific disease connections to investigate:

  • Microcephaly: Based on CNTROB's interaction with CPAP/CENPJ, a known microcephaly gene

  • Ciliopathies: Given CNTROB's role in primary ciliogenesis

  • Skeletal abnormalities: Informed by rat hypodactyly mutants with truncating CNTROB mutations

  • Male infertility: Based on defective sperm flagellar axoneme assembly in animal models

• Methodological approaches:

  • Multiplex immunofluorescence: Combine CNTROB staining with cell type-specific markers

  • Quantitative analysis: Measure centrosome number, size, and composition

  • Correlation studies: Link centrosome abnormalities to disease severity or progression

  • Functional studies: Assess impact of disease-associated mutations on CNTROB localization and function

• Technical considerations:

  • Use monoclonal antibodies (67061-1-Ig) for consistent results across multiple samples

  • Include proper controls (tissue-matched normal samples)

  • Optimize staining conditions for each tissue type

  • Consider automated image analysis for objective quantification

• Potential therapeutic implications:

  • Identify druggable interactions or pathways downstream of CNTROB

  • Screen for compounds that rescue CNTROB-related centrosomal defects

  • Develop biomarkers for disease progression or treatment response

What considerations are important when using CNTROB antibodies in combination with other centrosomal markers?

When using CNTROB antibodies alongside other centrosomal proteins, researchers should consider:

• Antibody compatibility:

  • Host species: Choose primary antibodies raised in different species (e.g., rabbit anti-CNTROB with mouse anti-γ-tubulin) to avoid cross-reactivity

  • Isotype considerations: For same-species antibodies, use different isotypes and isotype-specific secondary antibodies

  • Fluorophore selection: Use spectrally distinct fluorophores with minimal bleed-through

• Spatial relationships at centrosomes:

  • CNTROB localizes to daughter centrioles during centriole duplication

  • Consider using structured illumination microscopy (SIM) or other super-resolution approaches to resolve closely positioned proteins

  • Use centrin to mark distal centriole ends, γ-tubulin for pericentriolar material, and CP110 for distal centriole caps

• Temporal dynamics:

  • CNTROB localization may vary through the cell cycle

  • CP110 interaction with CNTROB is critical during ciliogenesis

  • Consider synchronized cells or cell cycle markers in co-staining experiments

• Fixation method optimization:

  • Different centrosomal proteins may require different fixation methods

  • Test both methanol and PFA fixation for optimal preservation of all target proteins

  • Consider testing combined fixation methods (e.g., PFA followed by methanol)

• Sequential immunostaining:

  • For challenging combinations, consider sequential staining protocols

  • Apply, image, and strip the first antibody before applying the second

  • Use zenon labeling kits for direct antibody labeling

• Recommended marker combinations:

  • CNTROB + γ-tubulin: To distinguish mother and daughter centrioles

  • CNTROB + CP110: To study their interaction during ciliogenesis

  • CNTROB + acetylated tubulin: To analyze the relationship between CNTROB and cilia formation

  • CNTROB + SAS-6: To study early centriole duplication events

• Controls for colocalization studies:

  • Include single-stained controls for each antibody

  • Use colocalization coefficients (Pearson's, Mander's) for quantification

  • Perform line scan analysis across centrosomes to demonstrate spatial relationships

• Data interpretation:

  • Consider the resolution limits of your imaging system

  • Use 3D reconstruction for complete centrosome visualization

  • Apply deconvolution to improve signal-to-noise ratio

What are the most promising future research directions involving CNTROB antibodies?

Emerging and promising research directions involving CNTROB antibodies include:

• High-resolution structural studies:

  • Applying super-resolution microscopy (PALM, STORM, STED) to map CNTROB's precise localization within centrioles

  • Using expansion microscopy to physically enlarge centrosomal structures for enhanced resolution

  • Correlative light and electron microscopy to link CNTROB localization to ultrastructural features

• Interactome mapping:

  • Proximity labeling approaches (BioID, APEX) to identify proteins in close proximity to CNTROB

  • Domain-specific interaction studies using truncated CNTROB constructs

  • Temporal analysis of CNTROB interactions throughout the cell cycle

  • Post-translational modification-dependent interactome changes

• Disease mechanisms:

  • Investigating CNTROB's potential role in primary microcephaly and ciliopathies

  • Analyzing CNTROB expression and localization in patient-derived samples

  • Developing zebrafish or mouse models with disease-specific CNTROB mutations

  • Exploring therapeutic approaches targeting CNTROB pathways

• Developmental biology applications:

  • Studying CNTROB dynamics during embryonic development

  • Investigating tissue-specific functions of CNTROB in specialized ciliated cells

  • Exploring the role of CNTROB in asymmetric cell division and differentiation

• Technical innovations:

  • Developing CNTROB nanobodies for live-cell imaging

  • Creating FRET-based sensors to monitor CNTROB interactions

  • Generating conformation-specific antibodies to detect specific CNTROB states

  • Adapting CNTROB antibodies for proximity ligation assays (PLA)

• Ciliogenesis mechanisms:

  • Further characterizing CNTROB's dual roles in CP110 regulation and microtubule stabilization

  • Investigating tissue-specific requirements for CNTROB in cilia formation

  • Exploring the relationship between CNTROB and ciliary signaling pathways

• Therapeutic applications:

  • Using CNTROB antibodies to screen for compounds that rescue centriole duplication or ciliogenesis defects

  • Developing CNTROB as a biomarker for centrosome-related diseases

  • Targeting CNTROB-dependent pathways for therapeutic intervention

These directions represent fertile ground for researchers to advance our understanding of centrosome biology and its implications for human health and disease, with CNTROB antibodies serving as crucial tools in these investigations.