CEP170 Antibody

What is CEP170 and why is it important in cellular research?

CEP170 (Centrosomal protein 170kDa) is a forkhead-associated (FHA) domain protein that plays a crucial role in microtubule organization and cell morphology. It primarily localizes to centrosomes during interphase and spindle microtubules during mitosis. Importantly, CEP170 serves as a specific marker for mature centrioles as it associates with subdistal appendages that are typical of the fully mature mother centriole . Research has demonstrated CEP170's interaction with Polo-like kinase 1 (Plk1), suggesting it functions as a physiological substrate of this important mitotic kinase . CEP170 is particularly valuable in research because it allows discrimination between distinct mechanisms of centriole accumulation and amplification in both normal and pathological cellular processes .

How do I select the appropriate CEP170 antibody for specific experimental applications?

Selection should be based on your specific application requirements and experimental design:

When selecting between antibodies, review validation data for your specific cellular model. For example, if studying centrosome maturation, prioritize antibodies specifically validated for subdistal appendage localization using electron microscopy techniques . For advanced applications requiring maximum specificity, consider monoclonal antibodies like AFFN-CEP170-20B9 which targets a specific 18.4 kDa protein fragment of CEP170 .

What are the optimal protocols for visualizing CEP170 in immunofluorescence studies?

For optimal CEP170 visualization in immunofluorescence studies:

• Cell Preparation:

  • Grow cells on coverslips to approximately 70% confluence

  • Fix with ice-cold methanol (-20°C) for 10 minutes, which preserves centrosomal structures better than formaldehyde fixation

  • Alternatively, use pre-extraction methods (0.5% Triton X-100 in PHEM buffer) prior to fixation to remove soluble cytoplasmic proteins

• Staining Protocol:

  • Block with 3% BSA in PBS for 30-60 minutes

  • Incubate with primary CEP170 antibody (typically at 1:50-1:500 dilution)

  • To clearly visualize centriole maturation, co-stain with γ-tubulin (centrosome marker) or centrin-2 (individual centriole marker)

  • For optimal visualization of subdistal appendages, super-resolution microscopy techniques yield superior results over standard confocal microscopy

• Result Interpretation:

  • In G1/S phase cells, expect CEP170 to associate with only one of two γ-tubulin–positive centrioles

  • In late G2 cells, CEP170 should be visible on both parental centrioles

  • Ring-shaped or three-dot patterns often indicate association with subdistal appendages

When troubleshooting, note that CEP170 staining patterns change dynamically throughout the cell cycle, which may explain variability between samples .

How can I effectively distinguish between mature and immature centrioles using CEP170 antibodies?

CEP170 serves as an excellent marker for centriole maturation, allowing researchers to effectively distinguish between mature and immature centrioles:

• Experimental Design:

  • Use dual immunostaining with CEP170 antibody and a general centriole marker (centrin-2) or centrosome marker (γ-tubulin)

  • For definitive identification of the older mother centriole, design experiments in serum-starved cells (e.g., NIH 3T3) where primary cilia form exclusively from the mature centriole

• Interpretation Guidelines:

  • Mature mother centrioles: Strong CEP170 staining, often ring-shaped or appearing as three distinct dots

  • Immature centrioles: Absence of CEP170 staining

  • During G1/S phase: Only one centriole (the older parental) shows CEP170 positivity

  • During late G2: Two centrioles typically show CEP170 staining

• Advanced Applications:

  • In cells with supernumerary centrosomes, CEP170 can help determine the mechanism of centriole amplification:

    • Normal number of CEP170-positive centrioles (1-2) with excess CEP170-negative centrioles suggests overduplication

    • Multiple CEP170-positive centrioles suggests failed cytokinesis with passage through mitosis

Research has demonstrated that this differential staining approach can be particularly valuable when investigating centrosome amplification in cancer cells or after viral oncoprotein (e.g., HPV16/E7) expression .

How can CEP170 antibodies be used to investigate the relationship between CEP170 and Plk1?

The interaction between CEP170 and Polo-like kinase 1 (Plk1) represents an important area of research that can be probed using specialized approaches with CEP170 antibodies:

• Co-immunoprecipitation Studies:

  • Immunoprecipitate CEP170 from cell lysates (particularly effective with HeLa cells) using anti-CEP170 antibodies

  • Probe western blots for co-precipitated Plk1

  • Reverse IP can validate the interaction (immunoprecipitate Plk1, probe for CEP170)

• Phosphorylation Analysis:

  • CEP170 is phosphorylated during mitosis and can be phosphorylated by Plk1 in vitro

  • Use phospho-specific antibodies after IP to detect phosphorylated CEP170

  • Perform λ-phosphatase treatment as a control to confirm phosphorylation status

  • Compare migration patterns of CEP170 in mitotic versus interphase cells on Phos-tag gels

• Localization Studies Throughout Cell Cycle:

  • Track both CEP170 and Plk1 localization throughout the cell cycle

  • Note that during mitosis, CEP170 association with centrosomes becomes more diffuse, and the protein associates with spindle microtubules near the poles

  • This dynamic localization correlates with Plk1 activity during cell cycle progression

These approaches can help elucidate the functional significance of CEP170 phosphorylation by Plk1 in centrosome maturation and microtubule organization.

What methodological approaches can be used to study the role of CEP170 in microtubule organization?

To investigate CEP170's role in microtubule organization, researchers can employ several methodological approaches:

• Overexpression and Depletion Studies:

  • Both overexpression and siRNA-mediated depletion of CEP170 affect microtubule organization and cell morphology

  • Transfect cells with CEP170 expression constructs or siRNA

  • Analyze changes in microtubule patterns using tubulin antibodies

  • Quantify alterations in cell morphology, particularly focusing on cell shape and size

• Nocodazole-Recovery Assays:

  • Treat cells with nocodazole to depolymerize microtubules

  • Wash out the drug and analyze microtubule regrowth patterns

  • Compare recovery in CEP170-depleted versus control cells

  • This approach helps determine CEP170's role in microtubule nucleation and organization

• Live-Cell Imaging Techniques:

  • Express fluorescently tagged CEP170 in live cells

  • Use time-lapse microscopy to monitor dynamics of CEP170 in relation to microtubule organization

  • Particularly useful for studying CEP170's role during mitotic progression

  • Can be combined with fluorescently labeled tubulin to simultaneously visualize microtubules

These methodological approaches can reveal CEP170's specific contributions to microtubule-dependent processes throughout the cell cycle.

What are the critical storage and handling requirements for maintaining CEP170 antibody efficacy?

Proper storage and handling of CEP170 antibodies is crucial for maintaining their efficacy and ensuring reproducible experimental results:

For optimal results:

• Centrifuge briefly before opening the vial to collect all liquid at the bottom

• When using small volumes, consider diluting a portion of the antibody in fresh buffer rather than using directly from the stock

• Document the number of freeze-thaw cycles and storage duration in laboratory records for troubleshooting purposes

• Note that 20μl-sized preparations often contain 0.1% BSA as additional stabilizer

What are common pitfalls when working with CEP170 antibodies and how can they be avoided?

Researchers working with CEP170 antibodies may encounter several common pitfalls:

• Variable Staining Patterns:

  • Problem: CEP170 shows dynamic cell cycle-dependent localization patterns that can be misinterpreted

  • Solution: Always synchronize cells or use cell cycle markers (e.g., PCNA for S phase) in co-staining experiments

  • Include positive controls with known CEP170 localization patterns (e.g., HeLa cells)

• Cross-Reactivity Issues:

  • Problem: Some CEP170 antibodies may cross-react with related centrosomal proteins

  • Solution: Validate antibody specificity using siRNA-mediated depletion of CEP170

  • Consider using peptide competition assays where the immunizing peptide blocks specific binding

  • When possible, confirm results with a second antibody raised against a different epitope

• Detection of Multiple Bands in Western Blot:

  • Problem: CEP170 has a calculated molecular weight of 165 kDa but is typically observed at 170-190 kDa

  • Solution: This discrepancy is normal and likely due to post-translational modifications

  • Note that phosphorylation states, particularly during mitosis, can further affect migration patterns

  • Always run appropriate positive controls (e.g., HeLa or MCF-7 cell lysates)

• Insufficient Antigen Exposure:

  • Problem: Limited accessibility of CEP170 epitopes, particularly at centrosomes

  • Solution: Optimize fixation methods; methanol fixation often works better than formaldehyde for centrosomal proteins

  • Consider pre-extraction treatments to remove cytoplasmic proteins before fixation

  • Extend primary antibody incubation times (overnight at 4°C) for better penetration

Proper experimental design with appropriate controls and optimization of protocols for specific applications will significantly improve results when working with CEP170 antibodies.

How can CEP170 antibodies be utilized to investigate centrosome abnormalities in cancer?

CEP170 antibodies offer unique opportunities for investigating centrosome abnormalities in cancer through several methodological approaches:

• Distinguishing Mechanisms of Centrosome Amplification:

  • CEP170 can discriminate between overduplication and aborted cell division mechanisms

  • In HPV16/E7-expressing cells, CEP170 staining reveals a normal number of mature centrioles (1-2) but an increased number of immature centrioles

  • This pattern differs from failed cytokinesis, where multiple mature (CEP170-positive) centrioles accumulate

  • Such distinction is critical for understanding the specific molecular pathways driving genomic instability in different cancer types

• Correlative Analysis with Cancer Progression:

  • Design tissue microarray studies using CEP170 antibodies alongside other centrosomal markers

  • Quantify the frequency of cells with abnormal CEP170 patterns across cancer stages

  • Correlate findings with clinical outcomes and genetic alterations

  • This approach can reveal whether specific centrosome maturation defects correlate with disease progression

• Drug Response Evaluation:

  • Use CEP170 antibodies to monitor centrosome integrity after treatment with drugs targeting cell cycle regulators

  • Evaluate whether drugs affecting Plk1 (which interacts with CEP170) influence centrosome maturation

  • Develop high-content screening approaches using CEP170 immunofluorescence to identify compounds that normalize centrosome abnormalities

These applications provide mechanistic insights into how centrosome abnormalities arise in cancer and may potentially identify new therapeutic targets or biomarkers.

What are the current methodological challenges in studying CEP170 post-translational modifications?

Studying CEP170 post-translational modifications presents several methodological challenges that researchers should consider:

Addressing these challenges requires integrated approaches combining biochemical, cell biological, and advanced microscopy techniques to fully understand how post-translational modifications regulate CEP170 function.