CEP135 Antibody

What is CEP135 and what cellular functions does it perform?

CEP135 (Centrosomal protein of 135 kDa) is a universal component of the centrosome present in a wide range of organisms. It is a scaffolding protein involved in centriole biogenesis that acts through multiple functions:

• Serves as a structural protein located at the centrosome throughout the cell cycle, with localization independent of the microtubule network

• Distributes throughout the centrosomal area in association with electron-dense material surrounding centrioles

• Required for the targeting of centriole satellite proteins to centrosomes (including PCM1, SSX2IP, and CEP290)

• Essential for centriole-centriole cohesion during interphase by acting as a platform protein for CEP250

• Facilitates the recruitment of CEP295 to the proximal end of new-born centrioles during early S phase in a PLK4-dependent manner

The protein is characterized by extensive α-helical domains with at least three independent centrosome-targeting domains spanning almost the entire length of its 1,145-amino acid sequence .

How does CEP135 participate in centrosome organization and microtubule networks?

CEP135 plays critical roles in centrosome organization and microtubule dynamics through several mechanisms:

• Acts as a scaffolding protein during early centriole biogenesis that provides structural support for centrosome assembly

• Influences microtubule organization, as demonstrated by experiments showing altered microtubule patterns following CEP135 overexpression or depletion via RNA interference (RNAi)

• When overexpressed, causes formation of unique whorl-like particles in both the centrosome and cytoplasm, composed of parallel dense lines arranged in a 6-nm space

• Essential for cell viability, as RNAi experiments have shown that significant reduction of endogenous CEP135 severely impacts cell growth

• Participates in proper chromosomal alignment and segregation, processes essential for avoiding aneuploidy and maintaining genomic stability

What are the key structural characteristics of CEP135 protein?

CEP135 exhibits several important structural features:

The protein's structure allows it to act as a scaffold, facilitating protein-protein interactions essential for centrosome function and organization .

What are the optimal applications for different types of CEP135 antibodies?

CEP135 antibodies can be used in various experimental applications with different optimal conditions:

For critical applications, validation experiments are recommended as reactivity may vary between antibodies from different vendors or different clones. Sample-dependent optimization is typically necessary to obtain optimal results .

How should CEP135 antibodies be stored and handled to maintain optimal activity?

Proper storage and handling are crucial for maintaining antibody activity:

• Store at -20°C for long-term storage; most CEP135 antibodies are stable for one year after shipment

• For short-term storage and frequent use, keep at 4°C for up to one month

• Avoid repeated freeze-thaw cycles as this can degrade antibody quality

• Most CEP135 antibodies are provided in liquid form with storage buffer containing stabilizers such as:

  • PBS with 0.02% sodium azide and 50% glycerol (pH 7.3)

  • Some preparations may contain 0.5% BSA

• Aliquoting is recommended for antibodies expected to be used multiple times, though some preparations specify that aliquoting is unnecessary for -20°C storage

• Exercise caution when handling as some preparations contain sodium azide, which is toxic and should be handled by trained staff only

What protocol modifications are necessary for detecting CEP135 in different cellular compartments?

Detecting CEP135 in different cellular compartments requires specific protocol adaptations:

For centrosome visualization:

• Use permeabilization with 0.3% PBST (PBS with Triton X-100) for 45 minutes to ensure adequate penetration of antibodies into centrosomal structures

• Block with 5% nonfat dry milk in PBST for 45 minutes to reduce nonspecific binding

• Co-staining with other centrosomal markers such as γ-tubulin or pericentrin is recommended to confirm centrosomal localization

• For best results, incubate primary antibodies in a humidified chamber at 4°C overnight

For immunoelectron microscopy:

• Fix cells and permeabilize with detergent before incubation with anti-CEP135 antibody

• Visualization requires gold-conjugated secondary antibodies to detect CEP135 around centrioles and in electron-dense material surrounding centrioles

For detecting CEP135 in specific structures like spermatozoa:

• Use specialized fixation methods appropriate for the tissue

• Co-localization with other markers like POC1B is recommended to precisely identify structures

What are common sources of variability in CEP135 antibody experiments and how can they be addressed?

Several factors can introduce variability in CEP135 antibody experiments:

• Epitope accessibility issues:

  • CEP135 is embedded within complex centrosomal structures

  • Solution: Optimize permeabilization conditions; try different detergents (Triton X-100, NP-40) or increase permeabilization time

• Cell cycle-dependent variations:

  • While CEP135 remains at the centrosome throughout the cell cycle, structural reorganization during mitosis may affect epitope accessibility

  • Solution: Synchronize cells or note cell cycle stage during analysis

• Antibody specificity:

  • Different antibodies target different regions of CEP135

  • Solution: Choose antibodies appropriate for your experiment (N-terminal vs. C-terminal targeting)

  • Example: Thermo Fisher 24428-1-AP targets amino acids 1-233 , while ABIN7184710 targets the C-terminal region

• Cross-reactivity:

  • Some antibodies may cross-react with other coiled-coil proteins

  • Solution: Validate specificity through knockout/knockdown controls or use multiple antibodies targeting different epitopes

• Background issues:

  • High background can mask specific CEP135 signals

  • Solution: Optimize blocking (5% nonfat dry milk or BSA), increase antibody dilution, or use more stringent washing

How can researchers validate CEP135 antibody specificity for their experimental system?

Rigorous validation is essential for ensuring CEP135 antibody specificity:

• Western blot validation:

  • Confirm single band of expected size (~135 kDa)

  • Check multiple cell lines as positive controls (A549, HeLa, U2OS cells are well-documented to express CEP135)

  • Include tissue/cells known to express high levels of CEP135

• RNAi or CRISPR knockout controls:

  • Perform CEP135 knockdown/knockout and confirm reduction/absence of signal

  • In one study, siRNA targeting CEP135 reduced protein levels by ~50% at 28h and ~70% at 48h after transfection

• Co-localization with established centrosomal markers:

  • Confirm that CEP135 co-localizes with γ-tubulin, pericentrin, or POC1B

  • For fibroblast cells, staining with POC1B, γ-tubulin, and tubulin can confirm proper centrosomal localization

• Multiple antibody approach:

  • Use antibodies targeting different epitopes and confirm similar localization patterns

  • Examples include: N-terminal targeting (Thermo Fisher 24428-1-AP) and C-terminal targeting (ABIN7184710)

• Mass spectrometry validation:

  • For advanced confirmation, immunoprecipitate with anti-CEP135 antibody and confirm protein identity by mass spectrometry

What controls should be included when using CEP135 antibodies in different applications?

Comprehensive control strategies for CEP135 antibody experiments include:

For Western blotting:

• Positive control: Cell lines with confirmed CEP135 expression (HeLa, Mouse Lung, COLO205, A549)

• Negative control: Samples treated with CEP135 siRNA showing reduced band intensity

• Loading control: Probing for housekeeping proteins (GAPDH, β-actin)

• Antibody specificity control: Pre-immune serum or isotype control antibody

For Immunofluorescence/ICC:

• Co-staining control: Other centrosomal markers (γ-tubulin, pericentrin) to confirm centrosomal localization

• Microtubule-independence control: Nocodazole-treated cells (CEP135 should remain at centrosomes even after microtubule depolymerization)

• Multiple centrosome control: p53-deficient mouse embryonic fibroblasts with multiple centrosomes allow confirmation of CEP135 localization at all centrosomes

• Peptide competition control: Pre-incubation of antibody with immunizing peptide should abolish specific staining

For RNA analysis:

• When analyzing CEP135 mRNA expression, include multiple primer sets targeting different regions

• In experiments analyzing CEP135 mutations (like c.970delC), design primers to amplify regions of different sizes to detect potential nonsense-mediated mRNA decay

How can CEP135 antibodies be used to investigate centrosome abnormalities in disease models?

CEP135 antibodies provide valuable tools for investigating centrosome abnormalities in various disease contexts:

• Primary microcephaly research:

  • CEP135 mutations cause primary microcephaly and abnormal centriole function

  • Antibodies can be used to examine the impact of specific mutations (e.g., c.970delC) on protein localization and centrosome structure

  • RT-PCR combined with immunofluorescence using CEP135 antibodies can determine if mutations trigger nonsense-mediated mRNA decay versus production of truncated proteins

• Cancer studies:

  • Centrosome amplification is a hallmark of many cancers

  • CEP135 antibodies can quantify centrosome number and morphology in cancer cells

  • Can be used to investigate whether CEP135 dysregulation contributes to genomic instability through abnormal mitotic spindle formation

• Cell division defects:

  • Antibodies can detect CEP135 mislocalization in cells with division defects

  • Overexpression studies with subsequent antibody staining can reveal formation of abnormal whorl-like structures in both the centrosome and cytoplasm

  • RNAi combined with immunofluorescence can assess how CEP135 depletion affects centrosome structure and function

• Spermatogenesis studies:

  • CEP135 plays critical roles in sperm morphology and function

  • Antibodies targeting specific regions (e.g., amino acids 1-233) can identify CEP135 localization in spermatozoa structures

  • Can be combined with other markers like POC1B to precisely map protein distribution in specialized cell types

What approaches can be used to study CEP135 protein-protein interactions in centrosome assembly?

Several sophisticated approaches can examine CEP135 protein-protein interactions:

• Proximity-based labeling techniques:

  • BioID or TurboID fusion with CEP135 to identify proteins in close proximity within centrosomes

  • APEX2 labeling to map the CEP135 interaction landscape with electron microscopy-level resolution

• Co-immunoprecipitation strategies:

  • Use anti-CEP135 antibodies to pull down protein complexes

  • Can identify interactions with known binding partners such as:

    • CEP250 (centriole-centriole cohesion)

    • WRAP73 (centriole recruitment)

    • CEP295 (recruitment to proximal end of new-born centrioles)

    • Satellite proteins like PCM1, SSX2IP, and CEP290

• Domain-specific interaction mapping:

  • Leverage the three independent centrosome-targeting domains identified in CEP135

  • Create deletion constructs similar to those used in previous studies (Δ2, Δ12, and #1) to map domain-specific interactions

  • Use antibodies against these domains to confirm localization patterns

• Super-resolution microscopy:

  • Combine CEP135 antibodies with super-resolution techniques (STORM, PALM, or SIM)

  • Precisely map CEP135 localization relative to other centrosomal proteins

  • Can reveal nanoscale organization within centrosomal substructures

• FRET/FLIM analysis:

  • Use fluorescently-tagged CEP135 constructs combined with antibody-based detection of potential interaction partners

  • Can provide evidence of direct protein-protein interactions in live cells

How can quantitative approaches be applied to CEP135 immunofluorescence data analysis?

Quantitative analysis of CEP135 immunofluorescence requires sophisticated approaches:

• Intensity-based quantification:

  • Measure fluorescence intensity of CEP135 signal at centrosomes

  • Can be used to quantify protein levels after experimental manipulations

  • Example application: Quantifying ~50% and ~70% reduction in CEP135 levels after 28h and 48h of siRNA treatment, respectively

• Spatial distribution analysis:

  • Map CEP135 distribution relative to centriolar landmarks

  • In spermatozoa studies, CEP135 has been mapped to precise locations: the proximal centriole base, distal centriole base, and striated columns

  • Analysis can involve measuring fluorescence intensity along a line spanning centrosomal structures

• Colocalization analysis:

  • Quantify overlap between CEP135 and other centrosomal markers

  • Example: CEP135 labeling colocalizes with POC1B but distributes over a slightly larger region (observed in 97% of spermatozoa, 29/30)

  • Can use Pearson's correlation coefficient or Manders' overlap coefficient for statistical evaluation

• High-content image analysis:

  • Automated detection and analysis of CEP135-positive structures across large cell populations

  • Can quantify parameters such as:

    • Number of CEP135-positive foci per cell

    • Size and intensity of each focus

    • Distance between foci in cells with multiple centrosomes

• Machine learning approaches:

  • Train algorithms to recognize specific CEP135 distribution patterns

  • Useful for identifying subtle phenotypes in disease models or after experimental manipulations

  • Can integrate multiple parameters for comprehensive phenotypic profiling

How should researchers interpret conflicting results from different CEP135 antibodies?

When faced with conflicting results from different CEP135 antibodies, researchers should systematically analyze several factors:

• Epitope differences:

  • Different antibodies target different regions of CEP135

  • N-terminal antibodies (e.g., amino acids 1-233) versus C-terminal antibodies may give different results if:

    • The protein undergoes post-translational modifications

    • Specific domains are masked by protein-protein interactions

    • Truncated forms of the protein are present

• Antibody validation status:

  • Evaluate the validation data for each antibody

  • Check if the antibody has been validated in your specific application and cell/tissue type

  • Antibodies validated through multiple approaches (WB, IF/ICC, knockout controls) provide higher confidence

• Technical considerations:

  • Fixation methods can affect epitope accessibility differently for different antibodies

  • Buffer conditions and blocking reagents may influence antibody performance

  • Antibody concentration and incubation time may need optimization for each antibody

• Reconciliation strategies:

  • Use multiple antibodies targeting different epitopes and report all results

  • Perform confirmatory experiments using alternative techniques (e.g., fluorescent protein tagging)

  • For controversial findings, combine antibody-based detection with functional assays or genetic approaches

• Publication reporting:

  • Clearly report which antibody was used, including catalog number and lot if possible

  • Describe all validation steps performed

  • Acknowledge limitations of antibody-based approaches in your interpretation

What insights can be gained from analyzing CEP135 mutations and their impact on centrosome function?

Analysis of CEP135 mutations provides critical insights into centrosome biology and disease mechanisms:

• Primary microcephaly mechanism:

  • CEP135 mutations (e.g., c.970delC resulting in p.Gln324Serfs*2) cause primary microcephaly (MCPH8)

  • Analysis reveals that mutations can lead to:

    • Truncated proteins missing critical functional domains

    • Nonsense-mediated mRNA decay (NMD) as demonstrated by RT-PCR experiments showing degradation of mutant mRNA

    • Defects in centriole duplication and microtubule organization

• Structure-function relationships:

  • Mapping mutations to specific domains helps identify critical functional regions

  • The three independent centrosome-targeting domains identified through deletion studies are likely crucial for proper localization and function

  • Correlation between mutation location and phenotype severity can reveal functional hierarchy

• Cell division impact:

  • CEP135 is essential for cell viability as demonstrated by RNAi experiments

  • Mutations affecting centriole biogenesis and microtubule organization can lead to:

    • Defective mitotic spindle formation

    • Chromosome segregation errors

    • Altered cell cycle progression

• Evolutionary insights:

  • CEP135 is present across diverse species from clam to human

  • Comparing effects of equivalent mutations across species can reveal evolutionarily conserved functions

  • Functional domains with highest conservation likely represent critical structural or interaction regions

• Therapeutic implications:

  • Understanding how specific mutations affect protein function can guide therapeutic approaches

  • For truncating mutations causing NMD, approaches targeting mRNA stability might be explored

  • For mutations affecting protein interactions, small molecule modulators of specific interactions could be designed

How does CEP135 expression and localization change during different cellular processes?

CEP135 exhibits distinct patterns during various cellular processes that can be studied with appropriate antibodies:

• Cell cycle progression:

  • CEP135 remains at the centrosome throughout the cell cycle

  • During S phase, it facilitates recruitment of CEP295 to new-born centrioles in a PLK4-dependent manner

  • During mitosis, it contributes to proper spindle formation and chromosome segregation

  • After mitosis, it participates in centriole-centriole cohesion by providing a platform for CEP250

• Centriole duplication:

  • Acts as a scaffolding protein during early centriole biogenesis

  • Required for targeted recruitment of centriole satellite proteins and other centrosomal components

  • Overexpression results in formation of unique whorl-like particles composed of parallel dense lines with 6-nm spacing

• Cellular differentiation:

  • In specialized cells like spermatozoa, CEP135 localizes to specific structures:

    • The proximal centriole base

    • The distal centriole base

    • The striated columns adjacent to the distal centriole

  • These specialized localization patterns can be detected using antibodies against specific regions (e.g., amino acids 1-233)

• Response to cellular stress:

  • Changes in CEP135 distribution or levels under stress conditions remain an area for investigation

  • Microtubule-depolymerizing agents like nocodazole do not affect CEP135 centrosomal localization, indicating its role as a structural component rather than a dynamic regulator

• Pathological states:

  • In contexts like microcephaly, mutations can lead to protein truncation or degradation via NMD

  • In p53-deficient cells with multiple centrosomes, CEP135 localizes to each centrosome, suggesting it plays a role in all centrosomes regardless of numerical abnormalities

Understanding these dynamic patterns requires careful experimental design with appropriate antibodies and controls to accurately track CEP135 behavior across different cellular states.

Comprehensive FAQs on CEP135 Antibody for Scientific Research

The following collection addresses key scientific questions about CEP135 antibodies, from fundamental properties to advanced experimental applications. These FAQs are designed to assist researchers working with this important centrosomal protein marker.

What is CEP135 and what cellular functions does it perform?

CEP135 (Centrosomal protein of 135 kDa) is a universal component of the centrosome present in a wide range of organisms. It is a scaffolding protein involved in centriole biogenesis that acts through multiple functions:

• Serves as a structural protein located at the centrosome throughout the cell cycle, with localization independent of the microtubule network

• Distributes throughout the centrosomal area in association with electron-dense material surrounding centrioles

• Required for the targeting of centriole satellite proteins to centrosomes (including PCM1, SSX2IP, and CEP290)

• Essential for centriole-centriole cohesion during interphase by acting as a platform protein for CEP250

• Facilitates the recruitment of CEP295 to the proximal end of new-born centrioles during early S phase in a PLK4-dependent manner

The protein is characterized by extensive α-helical domains with at least three independent centrosome-targeting domains spanning almost the entire length of its 1,145-amino acid sequence .

How does CEP135 participate in centrosome organization and microtubule networks?

CEP135 plays critical roles in centrosome organization and microtubule dynamics through several mechanisms:

• Acts as a scaffolding protein during early centriole biogenesis that provides structural support for centrosome assembly

• Influences microtubule organization, as demonstrated by experiments showing altered microtubule patterns following CEP135 overexpression or depletion via RNA interference (RNAi)

• When overexpressed, causes formation of unique whorl-like particles in both the centrosome and cytoplasm, composed of parallel dense lines arranged in a 6-nm space

• Essential for cell viability, as RNAi experiments have shown that significant reduction of endogenous CEP135 severely impacts cell growth

• Participates in proper chromosomal alignment and segregation, processes essential for avoiding aneuploidy and maintaining genomic stability

What are the key structural characteristics of CEP135 protein?

CEP135 exhibits several important structural features:

The protein's structure allows it to act as a scaffold, facilitating protein-protein interactions essential for centrosome function and organization .

What are the optimal applications for different types of CEP135 antibodies?

CEP135 antibodies can be used in various experimental applications with different optimal conditions:

For critical applications, validation experiments are recommended as reactivity may vary between antibodies from different vendors or different clones. Sample-dependent optimization is typically necessary to obtain optimal results .

How should CEP135 antibodies be stored and handled to maintain optimal activity?

Proper storage and handling are crucial for maintaining antibody activity:

• Store at -20°C for long-term storage; most CEP135 antibodies are stable for one year after shipment

• For short-term storage and frequent use, keep at 4°C for up to one month

• Avoid repeated freeze-thaw cycles as this can degrade antibody quality

• Most CEP135 antibodies are provided in liquid form with storage buffer containing stabilizers such as:

  • PBS with 0.02% sodium azide and 50% glycerol (pH 7.3)

  • Some preparations may contain 0.5% BSA

• Aliquoting is recommended for antibodies expected to be used multiple times, though some preparations specify that aliquoting is unnecessary for -20°C storage

• Exercise caution when handling as some preparations contain sodium azide, which is toxic and should be handled by trained staff only

What protocol modifications are necessary for detecting CEP135 in different cellular compartments?

Detecting CEP135 in different cellular compartments requires specific protocol adaptations:

For centrosome visualization:

• Use permeabilization with 0.3% PBST (PBS with Triton X-100) for 45 minutes to ensure adequate penetration of antibodies into centrosomal structures

• Block with 5% nonfat dry milk in PBST for 45 minutes to reduce nonspecific binding

• Co-staining with other centrosomal markers such as γ-tubulin or pericentrin is recommended to confirm centrosomal localization

• For best results, incubate primary antibodies in a humidified chamber at 4°C overnight

For immunoelectron microscopy:

• Fix cells and permeabilize with detergent before incubation with anti-CEP135 antibody

• Visualization requires gold-conjugated secondary antibodies to detect CEP135 around centrioles and in electron-dense material surrounding centrioles

For detecting CEP135 in specific structures like spermatozoa:

• Use specialized fixation methods appropriate for the tissue

• Co-localization with other markers like POC1B is recommended to precisely identify structures

What are common sources of variability in CEP135 antibody experiments and how can they be addressed?

Several factors can introduce variability in CEP135 antibody experiments:

• Epitope accessibility issues:

  • CEP135 is embedded within complex centrosomal structures

  • Solution: Optimize permeabilization conditions; try different detergents (Triton X-100, NP-40) or increase permeabilization time

• Cell cycle-dependent variations:

  • While CEP135 remains at the centrosome throughout the cell cycle, structural reorganization during mitosis may affect epitope accessibility

  • Solution: Synchronize cells or note cell cycle stage during analysis

• Antibody specificity:

  • Different antibodies target different regions of CEP135

  • Solution: Choose antibodies appropriate for your experiment (N-terminal vs. C-terminal targeting)

  • Example: Thermo Fisher 24428-1-AP targets amino acids 1-233 , while ABIN7184710 targets the C-terminal region

• Cross-reactivity:

  • Some antibodies may cross-react with other coiled-coil proteins

  • Solution: Validate specificity through knockout/knockdown controls or use multiple antibodies targeting different epitopes

• Background issues:

  • High background can mask specific CEP135 signals

  • Solution: Optimize blocking (5% nonfat dry milk or BSA), increase antibody dilution, or use more stringent washing

How can researchers validate CEP135 antibody specificity for their experimental system?

Rigorous validation is essential for ensuring CEP135 antibody specificity:

• Western blot validation:

  • Confirm single band of expected size (~135 kDa)

  • Check multiple cell lines as positive controls (A549, HeLa, U2OS cells are well-documented to express CEP135)

  • Include tissue/cells known to express high levels of CEP135

• RNAi or CRISPR knockout controls:

  • Perform CEP135 knockdown/knockout and confirm reduction/absence of signal

  • In one study, siRNA targeting CEP135 reduced protein levels by ~50% at 28h and ~70% at 48h after transfection

• Co-localization with established centrosomal markers:

  • Confirm that CEP135 co-localizes with γ-tubulin, pericentrin, or POC1B

  • For fibroblast cells, staining with POC1B, γ-tubulin, and tubulin can confirm proper centrosomal localization

• Multiple antibody approach:

  • Use antibodies targeting different epitopes and confirm similar localization patterns

  • Examples include: N-terminal targeting (Thermo Fisher 24428-1-AP) and C-terminal targeting (ABIN7184710)

• Mass spectrometry validation:

  • For advanced confirmation, immunoprecipitate with anti-CEP135 antibody and confirm protein identity by mass spectrometry

What controls should be included when using CEP135 antibodies in different applications?

Comprehensive control strategies for CEP135 antibody experiments include:

For Western blotting:

• Positive control: Cell lines with confirmed CEP135 expression (HeLa, Mouse Lung, COLO205, A549)

• Negative control: Samples treated with CEP135 siRNA showing reduced band intensity

• Loading control: Probing for housekeeping proteins (GAPDH, β-actin)

• Antibody specificity control: Pre-immune serum or isotype control antibody

For Immunofluorescence/ICC:

• Co-staining control: Other centrosomal markers (γ-tubulin, pericentrin) to confirm centrosomal localization

• Microtubule-independence control: Nocodazole-treated cells (CEP135 should remain at centrosomes even after microtubule depolymerization)

• Multiple centrosome control: p53-deficient mouse embryonic fibroblasts with multiple centrosomes allow confirmation of CEP135 localization at all centrosomes

• Peptide competition control: Pre-incubation of antibody with immunizing peptide should abolish specific staining

For RNA analysis:

• When analyzing CEP135 mRNA expression, include multiple primer sets targeting different regions

• In experiments analyzing CEP135 mutations (like c.970delC), design primers to amplify regions of different sizes to detect potential nonsense-mediated mRNA decay

How can CEP135 antibodies be used to investigate centrosome abnormalities in disease models?

CEP135 antibodies provide valuable tools for investigating centrosome abnormalities in various disease contexts:

• Primary microcephaly research:

  • CEP135 mutations cause primary microcephaly and abnormal centriole function

  • Antibodies can be used to examine the impact of specific mutations (e.g., c.970delC) on protein localization and centrosome structure

  • RT-PCR combined with immunofluorescence using CEP135 antibodies can determine if mutations trigger nonsense-mediated mRNA decay versus production of truncated proteins

• Cancer studies:

  • Centrosome amplification is a hallmark of many cancers

  • CEP135 antibodies can quantify centrosome number and morphology in cancer cells

  • Can be used to investigate whether CEP135 dysregulation contributes to genomic instability through abnormal mitotic spindle formation

• Cell division defects:

  • Antibodies can detect CEP135 mislocalization in cells with division defects

  • Overexpression studies with subsequent antibody staining can reveal formation of abnormal whorl-like structures in both the centrosome and cytoplasm

  • RNAi combined with immunofluorescence can assess how CEP135 depletion affects centrosome structure and function

• Spermatogenesis studies:

  • CEP135 plays critical roles in sperm morphology and function

  • Antibodies targeting specific regions (e.g., amino acids 1-233) can identify CEP135 localization in spermatozoa structures

  • Can be combined with other markers like POC1B to precisely map protein distribution in specialized cell types

What approaches can be used to study CEP135 protein-protein interactions in centrosome assembly?

Several sophisticated approaches can examine CEP135 protein-protein interactions:

• Proximity-based labeling techniques:

  • BioID or TurboID fusion with CEP135 to identify proteins in close proximity within centrosomes

  • APEX2 labeling to map the CEP135 interaction landscape with electron microscopy-level resolution

• Co-immunoprecipitation strategies:

  • Use anti-CEP135 antibodies to pull down protein complexes

  • Can identify interactions with known binding partners such as:

    • CEP250 (centriole-centriole cohesion)

    • WRAP73 (centriole recruitment)

    • CEP295 (recruitment to proximal end of new-born centrioles)

    • Satellite proteins like PCM1, SSX2IP, and CEP290

• Domain-specific interaction mapping:

  • Leverage the three independent centrosome-targeting domains identified in CEP135

  • Create deletion constructs similar to those used in previous studies (Δ2, Δ12, and #1) to map domain-specific interactions

  • Use antibodies against these domains to confirm localization patterns

• Super-resolution microscopy:

  • Combine CEP135 antibodies with super-resolution techniques (STORM, PALM, or SIM)

  • Precisely map CEP135 localization relative to other centrosomal proteins

  • Can reveal nanoscale organization within centrosomal substructures

• FRET/FLIM analysis:

  • Use fluorescently-tagged CEP135 constructs combined with antibody-based detection of potential interaction partners

  • Can provide evidence of direct protein-protein interactions in live cells

How can quantitative approaches be applied to CEP135 immunofluorescence data analysis?

Quantitative analysis of CEP135 immunofluorescence requires sophisticated approaches:

• Intensity-based quantification:

  • Measure fluorescence intensity of CEP135 signal at centrosomes

  • Can be used to quantify protein levels after experimental manipulations

  • Example application: Quantifying ~50% and ~70% reduction in CEP135 levels after 28h and 48h of siRNA treatment, respectively

• Spatial distribution analysis:

  • Map CEP135 distribution relative to centriolar landmarks

  • In spermatozoa studies, CEP135 has been mapped to precise locations: the proximal centriole base, distal centriole base, and striated columns

  • Analysis can involve measuring fluorescence intensity along a line spanning centrosomal structures

• Colocalization analysis:

  • Quantify overlap between CEP135 and other centrosomal markers

  • Example: CEP135 labeling colocalizes with POC1B but distributes over a slightly larger region (observed in 97% of spermatozoa, 29/30)

  • Can use Pearson's correlation coefficient or Manders' overlap coefficient for statistical evaluation

• High-content image analysis:

  • Automated detection and analysis of CEP135-positive structures across large cell populations

  • Can quantify parameters such as:

    • Number of CEP135-positive foci per cell

    • Size and intensity of each focus

    • Distance between foci in cells with multiple centrosomes

• Machine learning approaches:

  • Train algorithms to recognize specific CEP135 distribution patterns

  • Useful for identifying subtle phenotypes in disease models or after experimental manipulations

  • Can integrate multiple parameters for comprehensive phenotypic profiling

How should researchers interpret conflicting results from different CEP135 antibodies?

When faced with conflicting results from different CEP135 antibodies, researchers should systematically analyze several factors:

• Epitope differences:

  • Different antibodies target different regions of CEP135

  • N-terminal antibodies (e.g., amino acids 1-233) versus C-terminal antibodies may give different results if:

    • The protein undergoes post-translational modifications

    • Specific domains are masked by protein-protein interactions

    • Truncated forms of the protein are present

• Antibody validation status:

  • Evaluate the validation data for each antibody

  • Check if the antibody has been validated in your specific application and cell/tissue type

  • Antibodies validated through multiple approaches (WB, IF/ICC, knockout controls) provide higher confidence

• Technical considerations:

  • Fixation methods can affect epitope accessibility differently for different antibodies

  • Buffer conditions and blocking reagents may influence antibody performance

  • Antibody concentration and incubation time may need optimization for each antibody

• Reconciliation strategies:

  • Use multiple antibodies targeting different epitopes and report all results

  • Perform confirmatory experiments using alternative techniques (e.g., fluorescent protein tagging)

  • For controversial findings, combine antibody-based detection with functional assays or genetic approaches

• Publication reporting:

  • Clearly report which antibody was used, including catalog number and lot if possible

  • Describe all validation steps performed

  • Acknowledge limitations of antibody-based approaches in your interpretation

What insights can be gained from analyzing CEP135 mutations and their impact on centrosome function?

Analysis of CEP135 mutations provides critical insights into centrosome biology and disease mechanisms:

• Primary microcephaly mechanism:

  • CEP135 mutations (e.g., c.970delC resulting in p.Gln324Serfs*2) cause primary microcephaly (MCPH8)

  • Analysis reveals that mutations can lead to:

    • Truncated proteins missing critical functional domains

    • Nonsense-mediated mRNA decay (NMD) as demonstrated by RT-PCR experiments showing degradation of mutant mRNA

    • Defects in centriole duplication and microtubule organization

• Structure-function relationships:

  • Mapping mutations to specific domains helps identify critical functional regions

  • The three independent centrosome-targeting domains identified through deletion studies are likely crucial for proper localization and function

  • Correlation between mutation location and phenotype severity can reveal functional hierarchy

• Cell division impact:

  • CEP135 is essential for cell viability as demonstrated by RNAi experiments

  • Mutations affecting centriole biogenesis and microtubule organization can lead to:

    • Defective mitotic spindle formation

    • Chromosome segregation errors

    • Altered cell cycle progression

• Evolutionary insights:

  • CEP135 is present across diverse species from clam to human

  • Comparing effects of equivalent mutations across species can reveal evolutionarily conserved functions

  • Functional domains with highest conservation likely represent critical structural or interaction regions

• Therapeutic implications:

  • Understanding how specific mutations affect protein function can guide therapeutic approaches

  • For truncating mutations causing NMD, approaches targeting mRNA stability might be explored

  • For mutations affecting protein interactions, small molecule modulators of specific interactions could be designed

How does CEP135 expression and localization change during different cellular processes?

CEP135 exhibits distinct patterns during various cellular processes that can be studied with appropriate antibodies:

• Cell cycle progression:

  • CEP135 remains at the centrosome throughout the cell cycle

  • During S phase, it facilitates recruitment of CEP295 to new-born centrioles in a PLK4-dependent manner

  • During mitosis, it contributes to proper spindle formation and chromosome segregation

  • After mitosis, it participates in centriole-centriole cohesion by providing a platform for CEP250

• Centriole duplication:

  • Acts as a scaffolding protein during early centriole biogenesis

  • Required for targeted recruitment of centriole satellite proteins and other centrosomal components

  • Overexpression results in formation of unique whorl-like particles composed of parallel dense lines with 6-nm spacing

• Cellular differentiation:

  • In specialized cells like spermatozoa, CEP135 localizes to specific structures:

    • The proximal centriole base

    • The distal centriole base

    • The striated columns adjacent to the distal centriole

  • These specialized localization patterns can be detected using antibodies against specific regions (e.g., amino acids 1-233)

• Response to cellular stress:

  • Changes in CEP135 distribution or levels under stress conditions remain an area for investigation

  • Microtubule-depolymerizing agents like nocodazole do not affect CEP135 centrosomal localization, indicating its role as a structural component rather than a dynamic regulator

• Pathological states:

  • In contexts like microcephaly, mutations can lead to protein truncation or degradation via NMD

  • In p53-deficient cells with multiple centrosomes, CEP135 localizes to each centrosome, suggesting it plays a role in all centrosomes regardless of numerical abnormalities