cep72 Antibody

What is CEP72 and what cellular structures does it localize to?

CEP72 is a 72 kDa centrosomal protein (646 amino acids) that primarily localizes to the centrosome and centrosome-surrounding particles throughout the cell cycle . Immunofluorescence studies using anti-CEP72 antibodies show that CEP72 distribution closely resembles that of centriolar satellites, with particles that disappear after microtubule depolymerization with nocodazole, indicating that CEP72-associating particles localize in a microtubule-dependent manner . Some centrosome-surrounding CEP72 particles have also been observed in close proximity to Golgi membranes, suggesting potential interactions with Golgi-associated structures .

What are the typical applications for CEP72 antibody in research?

CEP72 antibodies are employed in multiple experimental approaches as evidenced by published applications:

These applications have been documented across human, mouse, and rat samples, with demonstrated reactivity in various cell types including HeLa, HEK-293, and testis tissue . The antibody is valuable for studying centrosome biology, centriolar satellites, and microtubule organization in both normal and pathological contexts.

How should CEP72 antibody be stored and handled to maintain its efficacy?

For optimal results with CEP72 antibody, proper storage and handling are essential:

• Store at -20°C where it remains stable for one year after shipment

• Aliquoting is unnecessary for -20°C storage (according to manufacturer specifications)

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

• Smaller (20μl) sizes may contain 0.1% BSA as a stabilizer

• Avoid repeated freeze-thaw cycles to preserve antibody integrity

• Follow manufacturer's recommendations for specific lot numbers as performance may vary slightly

What is the role of CEP72 in centrosomal protein recruitment?

CEP72 functions as a critical protein for the proper localization of several centrosomal components. Research using CEP72-specific antibodies and RNAi depletion has revealed:

CEP72 regulates the centrosomal localization of:

Importantly, CEP72 depletion does not affect pericentrin localization, indicating specificity in its recruitment functions . These findings establish CEP72 as a key protein in ensuring proper centrosomal composition and subsequent microtubule organization.

How does CEP72 interact with PCM1 and what is its role in centriolar satellites?

CEP72 has been identified as a PCM1-interacting protein that is required for recruitment of Cep290 (a ciliopathy-associated protein) to centriolar satellites . Key findings include:

• Endogenous CEP72 co-immunoprecipitates with PCM1 from hTERT-RPE1 cells, confirming their interaction in vivo

• CEP72 and PCM1 maintain colocalization even when normal distribution of centriolar satellites is disrupted by nocodazole treatment or p50 dynamitin expression

• Depletion of either CEP72 or Cep290 results in significant (p<0.001) redistribution of centriolar satellites, with increased pericentrosomal PCM1 and reduced cytoplasmic satellites

• The pattern of evolutionary conservation for CEP72 mirrors that of PCM1, supporting their functional relationship

This interaction appears crucial for proper centriolar satellite distribution and function, with implications for ciliopathy-related research.

What is the connection between CEP72 genetic variants and vincristine-induced peripheral neuropathy?

A particularly significant discovery in CEP72 research is the association between CEP72 genetic polymorphisms and susceptibility to vincristine-induced peripheral neuropathy:

• An inherited polymorphism in the promoter region of CEP72 (rs924607, T allele) increases the risk and severity of vincristine-related peripheral neuropathy

• This risk allele has a lower frequency in people of African ancestry compared to European ancestry, which correlates with the reported lower frequency of vincristine-induced neuropathy in Black patients

• The promoter SNP alters CEP72 expression (lower with the risk allele), which is presumed to increase cellular sensitivity to vincristine (a microtubule inhibitor)

• CEP72 knockdown in human iPSC neurons and ALL cells increases their sensitivity to vincristine

• This represents a pharmacodynamic mechanism for a pharmacogenomic trait, whereby lower CEP72 expression compromises microtubule formation through a mechanism distinct from vincristine's action

This discovery has clinical implications, suggesting that patients with the high-risk CEP72 genotype might benefit from adjusted vincristine dosing, a hypothesis being investigated in clinical trials .

What are the recommended protocols and dilutions for different applications of CEP72 antibody?

Based on validated experimental approaches, the following recommendations are provided for CEP72 antibody applications:

It is recommended that these dilutions be titrated in each specific testing system to obtain optimal results, as sample-dependent variations may occur . Following standardized protocols while adjusting for specific experimental conditions will enhance reproducibility and data quality.

How can researchers validate the specificity of CEP72 antibody signals?

Several approaches have been documented to validate CEP72 antibody specificity:

• Reciprocal immunoprecipitation experiments showing association of endogenous CEP72 with interacting partners like Kiz

• Comparison of endogenous protein localization with exogenously expressed Myc-tagged CEP72, which should show similar localization patterns

• RNAi-mediated depletion of CEP72, which should significantly reduce antibody signal in both Western blotting and immunofluorescence

• Antibody blocking experiments using GST-CEP72 antigen, which should eliminate specific signal

• Correlation of molecular weight detection (expected 72 kDa) with detection of CEP72-GFP expressed in cells (showing appropriate size shift)

These validation approaches are critical for ensuring experimental rigor, especially when investigating novel CEP72 functions or interactions.

What controls should be included in CEP72 knockdown experiments?

When designing CEP72 knockdown experiments, several controls are essential:

In published studies, CEP72 knockdown has been used to demonstrate its role in γTuRC localization, with knockdown efficiencies verified by Western blotting showing >90% reduction in CEP72 signal .

Why might CEP72 signals be weak or absent in immunofluorescence experiments?

Several factors may contribute to weak or absent CEP72 signals in immunofluorescence:

• Microtubule integrity: CEP72 localization to centriolar satellites is microtubule-dependent, and treatment with microtubule-depolymerizing drugs like nocodazole disrupts its normal distribution pattern . Fixation methods that do not preserve microtubules may result in altered CEP72 localization.

• Cell cycle phase: While CEP72 localizes to centrosomes throughout the cell cycle, the intensity and pattern of localization may vary. Cell synchronization may be needed to observe specific patterns.

• Antibody dilution: The recommended dilution range for immunofluorescence is 1:200-1:800 . Using too dilute antibody solutions may result in weak signals.

• Fixation method: Inappropriate fixation can affect epitope accessibility. Published protocols typically use paraformaldehyde fixation for CEP72 immunostaining.

• Protein interactions: CEP72 interactions with other proteins may mask epitopes in certain cellular contexts.

How can researchers differentiate between specific and non-specific signals in Western blots using CEP72 antibody?

To distinguish specific from non-specific signals when using CEP72 antibody in Western blots:

• Verify the molecular weight: CEP72 has a calculated molecular weight of 72 kDa (646 amino acids), which should be the predominant band in Western blots .

• Use positive controls: Mouse/rat testis tissue and HEK-293 cells have been validated as positive controls for CEP72 detection .

• Include RNAi-treated samples: Samples from cells with RNAi-mediated CEP72 depletion should show significantly reduced signal at the expected molecular weight .

• Pre-absorption control: Pre-incubation of the antibody with the immunizing peptide or recombinant CEP72 protein should abolish specific signals.

• Detection of tagged CEP72: Compare with samples expressing tagged versions of CEP72 (e.g., Myc-CEP72 or CEP72-GFP), which should show bands of correspondingly higher molecular weight .

How does CEP72 expression level affect sensitivity to microtubule inhibitors?

Research into the relationship between CEP72 expression and microtubule inhibitor sensitivity has revealed important pharmacogenomic implications:

• Lower CEP72 expression (associated with the T allele at rs924607 in the promoter region) increases cellular sensitivity to vincristine, a microtubule inhibitor used in cancer chemotherapy .

• This sensitivity appears to occur through a pharmacodynamic mechanism: Since CEP72 is essential for normal microtubule formation, reduced CEP72 expression compromises microtubule formation through a mechanism distinct from vincristine's action, essentially making cells more vulnerable to the drug's effects .

• Experimental evidence includes:

  • Knockdown of CEP72 in human iPSC neurons increases their sensitivity to vincristine

  • Similar increased sensitivity is observed when CEP72 is knocked down in human ALL cells

  • Primary ALL cells from patients with the high-risk CEP72 T/T promoter genotype show greater ex vivo sensitivity to vincristine

These findings have led to the hypothesis that patients with the high-risk genotype might be successfully treated with lower vincristine dosages, as both their leukemia cells and neurons show increased sensitivity. This is currently being investigated in a prospective randomized clinical trial .

What is known about CEP72's role in regulating microtubule organization and nucleation?

CEP72 plays a crucial role in microtubule organization at the centrosome:

• In CEP72-depleted cells, microtubule re-growth from centrosomes after nocodazole washout is severely impaired (only 6.5±1.9% of cells show microtubules longer than the threshold at 5 minutes post-recovery, compared to 72.5±2.9% in control cells) .

• This impairment is associated with reduced γ-tubulin and GCP2 (γTuRC components) localization to centrosomes .

• CEP72 is also required for the centrosomal localization of CG-NAP, another protein crucial for microtubule nucleation .

• Interestingly, CG-NAP depletion does not affect γ-tubulin localization but still severely impairs microtubule nucleation, indicating that proper microtubule organization requires both the recruitment of γTuRCs and their activation/organization by factors like CG-NAP .

These findings establish CEP72 as a key protein in ensuring the microtubule-organizing activity of interphase centrosomes through its role in recruiting both γTuRCs and their regulatory factors.