GO:0046603 negative regulation of mitotic centrosome separation: Centrosome Linker Control, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0046603 describes any process that stops, prevents, or reduces the frequency, rate or extent of centrosome separation, a critical step in mitotic spindle assembly.
• Centrosome separation is driven by linker disassembly and motor proteins; negative regulation often involves kinase signaling that stabilizes the linker or delays separation.
• Key regulators include NEK2, NEK5, BubR1, separase, and TRIM37, which modulate centrosome dynamics and mitotic fidelity [1,3,5,6,7].
• Dysregulation of this process leads to centrosome amplification, aneuploidy, and is implicated in cancers such as breast cancer and multiple myeloma [1,2].
• Experimental models include CRISPR knockout, point mutation, knock-in, and overexpression of centrosomal genes to dissect their roles in mitotic progression [5,8].
• Understanding GO:0046603 provides insights into mitotic regulation and potential therapeutic targets for taxane-resistant cancers and other proliferative disorders.
Description
The negative regulation of mitotic centrosome separation (GO:0046603) is a biological process that prevents or reduces the separation of centrosomes during mitosis. Centrosome separation is essential for bipolar spindle formation and accurate chromosome segregation, and its dysregulation can lead to aneuploidy and cancer. This process is tightly controlled by a network of kinases, phosphatases, and structural proteins that ensure timely separation. Research into GO:0046603 has revealed critical roles for NEK2, NEK5, BubR1, and separase in modulating centrosome linker dynamics and mitotic progression [3,4,5,6,7]. Understanding these mechanisms is vital for developing therapeutic strategies against cancers characterized by centrosome amplification [1,2].
negative regulation of mitotic centrosome separation At A Glance
| GO ID | GO:0046603 |
|---|---|
| GO term | negative regulation of mitotic centrosome separation |
| Ontology | biological_process |
| Synonym | down regulation of mitotic centrosome separation, down-regulation of mitotic centrosome separation, downregulation of mitotic centrosome separation, inhibition of mitotic centrosome separation |
| Major function | Prevents or delays centrosome separation during mitosis to ensure proper spindle assembly and chromosome segregation. |
| Related processes | Mitotic spindle organization, centrosome cycle, cell cycle checkpoint control. |
| Key regulators | NEK2, NEK5, BubR1, separase, TRIM37. |
| Disease relevance | Centrosome amplification, aneuploidy, breast cancer, multiple myeloma, taxane resistance. |
What Is GO:0046603?
GO:0046603, negative regulation of mitotic centrosome separation, encompasses any process that stops, prevents, or reduces the frequency, rate, or extent of centrosome separation. This regulation ensures that centrosome separation occurs at the correct time and place during mitosis, preventing premature or aberrant separation that could lead to spindle defects.
Why Is negative regulation of mitotic centrosome separation Important in Cell Biology?
Proper regulation of centrosome separation is crucial for mitotic fidelity. Negative regulation ensures that separation occurs only after key mitotic events, such as centrosome maturation and linker disassembly, are completed. Disruption of this regulation can cause premature separation, leading to multipolar spindles, aneuploidy, and cell death, or contribute to tumorigenesis through centrosome amplification [1,2]. Thus, understanding GO:0046603 offers insights into basic cell biology and cancer therapy.
• Prevents premature centrosome separation, which can cause multipolar spindles and aneuploidy.
• Regulates mitotic timing and ensures accurate chromosome segregation.
• Dysregulation is linked to centrosome amplification, a hallmark of many cancers.
• Involved in resistance to taxane-based chemotherapies.
• Provides potential targets for cancer therapy, such as NEK2 inhibitors.
• Plays a role in normal development and tissue homeostasis.
• Implicated in multiple myeloma pathogenesis.
• Modulated by signaling pathways like PLK1 and Aurora A.
• Key for understanding mitotic checkpoints and cell cycle control.
• Offers avenues for CRISPR-based functional studies.
What Happens During negative regulation of mitotic centrosome separation?
Centrosome Linker Stabilization
In simple terms: The centrosome linker is a protein bridge that holds the two centrosomes together; keeping it stable prevents them from separating too early.
During early mitosis, the centrosome linker, composed of proteins like C-Nap1 and rootletin, maintains centrosome cohesion. Negative regulation of separation involves stabilizing this linker or delaying its disassembly. NEK2 kinase phosphorylates linker proteins, promoting their disassembly, but negative regulators can counteract this by dephosphorylation or by inhibiting NEK2 activity. For example, Dishevelled is a NEK2 substrate that controls dynamics of centrosomal linker proteins, and its modulation can influence separation timing.
Inhibition of Separase Activity
In simple terms: Separase is an enzyme that cuts the linker; blocking it keeps centrosomes together.
Separase is a protease that cleaves cohesin and also plays a role in centrosome separation by cleaving linker proteins. Negative regulation can occur through inhibition of separase activity. In BCR-ABL-positive cells, imatinib increases separase proteolytic activity, suggesting that BCR-ABL signaling negatively regulates separase, thereby affecting centrosome separation. Thus, modulation of separase activity is a key mechanism in negative regulation of centrosome separation.
Kinase Signaling Pathways
In simple terms: Kinases are enzymes that add phosphate groups; some kinases act as brakes on centrosome separation.
Several kinases are involved in negatively regulating centrosome separation. BubR1 localizes to centrosomes and suppresses centrosome amplification by regulating Plk1 activity in interphase cells. NEK5, a member of the NIMA-related kinase family, regulates biological pathways and processes in breast epithelial cells, including centrosome dynamics. NEK2, on the other hand, promotes separation, so its inhibition is a form of negative regulation [4,5]. The balance between these kinases determines the timing of separation.
Role of TRIM37 in Centrosome Regulation
In simple terms: TRIM37 is a protein that helps keep centrosomes in check; when it is overactive, it can prevent proper separation.
TRIM37 is a E3 ubiquitin ligase that localizes to centrosomes and regulates their function. In 17q23-amplified breast cancer, TRIM37 overexpression drives centrosome dysfunction, including impaired separation, leading to mitotic defects. Targeting TRIM37 restores proper centrosome separation and reduces tumor growth, highlighting its role in negative regulation.
Checkpoint Control and Temporal Regulation
In simple terms: The cell has checkpoints that ensure everything is ready before centrosomes separate; negative regulation is part of this quality control.
The G2/M checkpoint and spindle assembly checkpoint (SAC) coordinate centrosome separation with other mitotic events. Negative regulation ensures that separation does not occur until chromosomes are properly aligned and the spindle is ready. BubR1, a SAC component, also localizes to centrosomes and suppresses premature separation. This integration prevents errors that could lead to aneuploidy.
Key Genes Involved in GO:0046603 negative regulation of mitotic centrosome separation
The following genes and proteins are key players in the negative regulation of mitotic centrosome separation, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| NEK2 | Kinase that promotes centrosome separation by phosphorylating linker proteins; its inhibition negatively regulates separation. | Target for overcoming taxane resistance; core regulator of mitotic fidelity. |
| NEK5 | NIMA-related kinase involved in centrosome dynamics and mitotic regulation. | Regulates pathways in breast epithelial cells; potential role in cancer. |
| BubR1 | Localizes to centrosomes and suppresses centrosome amplification via Plk1 regulation. | Key mitotic checkpoint protein; links SAC to centrosome regulation. |
| Separase | Protease that cleaves cohesin and linker proteins; its activity is modulated to delay separation. | Implicated in BCR-ABL signaling; target of imatinib. |
| TRIM37 | E3 ubiquitin ligase that regulates centrosome function; overexpression impairs separation. | Driver of centrosome dysfunction in 17q23-amplified breast cancer. |
| Plk1 | Kinase that promotes centrosome maturation and separation; BubR1 regulates its activity. | Central to mitotic progression; target for cancer therapy. |
| Dishevelled | NEK2 substrate controlling dynamics of centrosomal linker proteins. | Links Wnt signaling to centrosome regulation. |
| C-Nap1 | Centrosome linker protein; its phosphorylation by NEK2 leads to linker disassembly. | Structural component of the linker; regulates separation timing. |
| Rootletin | Centrosome linker protein; interacts with C-Nap1 to maintain cohesion. | Essential for linker integrity; regulated by NEK2. |
| Aurora A | Kinase that promotes centrosome maturation and separation. | Often overexpressed in cancers; interacts with BubR1 pathway. |
| CDK1 | Cyclin-dependent kinase that drives mitotic entry and centrosome separation. | Master regulator of mitosis; modulates NEK2 activity. |
| PP1 | Protein phosphatase that can counteract kinase activity, promoting linker stability. | Potential negative regulator of separation. |
| Mps1 | Kinase involved in SAC and centrosome duplication. | Regulates centrosome cycle; potential link to separation. |
| Sgo1 | Protects centromeric cohesion; may influence centrosome separation indirectly. | Role in mitotic fidelity. |
| Cyclin B | Regulatory subunit of CDK1; controls mitotic progression. | Modulates timing of centrosome separation. |
| APC/C | Ubiquitin ligase that targets securin for degradation, releasing separase. | Indirectly regulates separation by controlling separase activity. |
| Securin | Inhibits separase; its degradation is required for separase activation. | Regulates timing of separase-mediated events. |
| Emi1 | Inhibits APC/C, thereby preventing separase activation and separation. | Negative regulator of mitotic progression. |
How Is negative regulation of mitotic centrosome separation Regulated?
The negative regulation of mitotic centrosome separation is controlled by a balance of kinase and phosphatase activities, ubiquitin-mediated proteolysis, and checkpoint signaling. NEK2 kinase promotes separation by phosphorylating linker proteins, so its inhibition or degradation negatively regulates separation [4,5]. Conversely, phosphatases like PP1 may stabilize the linker by dephosphorylating these proteins. The spindle assembly checkpoint (SAC) delays separation until chromosomes are properly attached; BubR1, a SAC component, localizes to centrosomes and suppresses premature separation by regulating Plk1. Additionally, the APC/C-securin-separase axis controls the timing of separase activation, which cleaves linker proteins; inhibition of APC/C or securin stabilization prevents separase activation and delays separation. TRIM37, an E3 ubiquitin ligase, regulates centrosome protein stability and its overexpression impairs separation. These regulatory layers ensure that centrosome separation occurs only when appropriate.
negative regulation of mitotic centrosome separation and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TRIM37 | 17q23-amplified breast cancer; centrosome dysfunction | CRISPR knockout or overexpression in breast cancer cell lines (e.g., MCF7) |
| NEK2 | Taxane-resistant cancers; mitotic fidelity | Knockout or point mutation in cancer cell lines; xenograft models |
| BubR1 | Centrosome amplification; aneuploidy | Knockout or knockdown in HeLa or RPE1 cells |
| Separase | BCR-ABL-positive leukemia; imatinib response | Point mutation of cleavage sites; BCR-ABL cell lines |
| NEK5 | Breast epithelial cell pathways; potential cancer role | Knockout in breast epithelial cells; proteomic analysis |
Cancer and Centrosome Amplification
Dysregulation of negative regulation of centrosome separation leads to centrosome amplification, a hallmark of many cancers. In 17q23-amplified breast cancer, TRIM37 overexpression causes centrosome dysfunction and impaired separation, contributing to tumorigenesis. Targeting TRIM37 restores proper separation and reduces tumor growth, suggesting therapeutic potential. Similarly, multiple myeloma patients often exhibit centrosome amplification, which correlates with disease progression and poor prognosis.
Taxane Resistance
NEK2 and LIN9 are core regulators of mitotic fidelity, and their overexpression contributes to taxane resistance in cancers. Targeting NEK2 can overcome taxane resistance by inducing mitotic catastrophe, highlighting the importance of negative regulation of centrosome separation in chemoresistance.
Leukemia and BCR-ABL Signaling
In BCR-ABL-positive leukemias, imatinib treatment increases separase proteolytic activity, which may affect centrosome separation. This suggests that BCR-ABL signaling negatively regulates separase, and its inhibition could alter centrosome dynamics, potentially impacting disease progression.
From negative regulation of mitotic centrosome separation-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X negatively regulate centrosome separation? | CRISPR knockout of gene X in HeLa cells, followed by immunofluorescence for centrosome separation markers. |
| What is the role of a specific phosphorylation site in NEK2? | Point mutation (e.g., kinase-dead or phospho-mimetic) knock-in in cancer cell lines. |
| How does TRIM37 overexpression affect centrosome separation? | Overexpression of TRIM37 in breast cancer cell lines, assessing centrosome amplification. |
| Does BubR1 regulate Plk1 at centrosomes? | Knockout of BubR1 with rescue by wild-type or mutant BubR1. |
| Can NEK2 inhibition overcome taxane resistance? | CRISPR knockout or small molecule inhibitor in taxane-resistant cell lines. |
| What is the effect of separase cleavage-resistant mutations? | Point mutation of separase cleavage sites in BCR-ABL cells. |
How to Study the negative regulation of mitotic centrosome separation Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Immunofluorescence | Distance between centrosomes; separation status | Assessing gene knockout effects on separation. |
| Live-cell imaging | Dynamics of centrosome separation over time | Real-time analysis of separation delays. |
| Proteomics | Protein expression and phosphorylation changes | Identifying signaling pathways regulating separation. |
| CRISPR screening | Genes whose loss affects separation | Discovery of novel regulators. |
| Western blot | Protein levels and phosphorylation status | Validating kinase activity and expression. |
| Co-immunoprecipitation | Protein-protein interactions | Studying linker complex composition. |
| Flow cytometry | Cell cycle profile and aneuploidy | Assessing mitotic defects. |
| RNA-seq | Transcriptional changes | Global effects of regulators on gene expression. |
Immunofluorescence Microscopy
Immunofluorescence is a key method to visualize centrosome separation. Antibodies against centrin or pericentrin mark centrosomes, and separation is measured as the distance between the two centrosomes. This method can be used in fixed cells to assess the effects of gene knockout or overexpression on separation [1,7].
Live-Cell Imaging
Live-cell imaging with fluorescently tagged centrosomal proteins (e.g., GFP-centrin) allows real-time monitoring of centrosome separation dynamics. This technique can reveal delays or premature separation in response to genetic perturbations.
Proteomics and Phosphoproteomics
Mass spectrometry-based proteomics can identify changes in protein phosphorylation and interactions that regulate centrosome separation. For example, NEK5-regulated pathways were identified via integrated proteomic approaches in breast epithelial cells.
CRISPR Screening
Genome-wide CRISPR knockout screens can identify genes that negatively regulate centrosome separation. Cells with aberrant separation can be selected by flow cytometry or imaging, and sgRNAs enriched in those populations reveal candidate regulators [5,8].
How CRISPR Can Be Used to Study GO:0046603 negative regulation of mitotic centrosome separation
Knockout
CRISPR knockout of genes involved in negative regulation of centrosome separation, such as NEK2 or BubR1, can reveal their essential roles. For example, NEK2 knockout leads to premature centrosome separation and mitotic defects, confirming its function as a positive regulator. Knockout of TRIM37 in 17q23-amplified breast cancer cells restores proper separation, demonstrating its role in negative regulation.
Point Mutation
Point mutations can dissect specific domains or phosphorylation sites. For instance, mutating NEK2 kinase domain or its substrate-binding sites can clarify how it regulates linker proteins. Similarly, mutating separase cleavage sites can prevent linker cleavage, affecting separation.
Knock-in
Knock-in of tagged versions of centrosomal proteins (e.g., GFP-C-Nap1) allows visualization and tracking of linker dynamics. This approach can be used to study how mutations affect protein localization and separation timing.
Overexpression
Overexpression of negative regulators like TRIM37 or BubR1 can suppress centrosome separation, leading to mitotic defects. This is useful to model diseases characterized by centrosome amplification, such as breast cancer [1,7].
How EDITGENE Supports negative regulation of mitotic centrosome separation Research
Researchers studying negative regulation of mitotic centrosome separation-related genes often need to determine whether a candidate gene is causally involved in the process or is merely correlated with it. EDITGENE provides a comprehensive suite of CRISPR services to enable such functional studies.
Contact EDITGENE today to design your custom CRISPR model for negative regulation of mitotic centrosome separation research.
Frequently Asked Questions About negative regulation of mitotic centrosome separation
What is GO:0046603?
GO:0046603 is the Gene Ontology term for negative regulation of mitotic centrosome separation, describing any process that prevents or reduces the separation of centrosomes during mitosis.
What genes are involved in negative regulation of mitotic centrosome separation?
Key genes include NEK2, NEK5, BubR1, separase, and TRIM37, which modulate centrosome linker dynamics and mitotic progression [1,3,4,5,6,7].
Why is negative regulation of centrosome separation important?
It ensures proper timing of centrosome separation, preventing aneuploidy and maintaining genomic stability; dysregulation is linked to cancer [1,2].
How is centrosome separation negatively regulated?
Through kinase signaling (e.g., BubR1, NEK5), protease inhibition (separase), and ubiquitin-mediated processes (TRIM37) that stabilize the centrosome linker or delay its disassembly [1,3,4,6,7].
What diseases are associated with defects in this process?
Centrosome amplification and aneuploidy are associated with breast cancer, multiple myeloma, and taxane-resistant cancers [1,2,5].
What methods are used to study negative regulation of mitotic centrosome separation?
Immunofluorescence, live-cell imaging, proteomics, and CRISPR screening are commonly used to assess centrosome separation and identify regulators [1,4,5,6].
How can CRISPR help study GO:0046603?
CRISPR knockout, point mutation, knock-in, and overexpression enable functional dissection of genes involved in centrosome separation [1,3,4,5,7].
What is the role of NEK2 in centrosome separation?
NEK2 kinase promotes centrosome separation by phosphorylating linker proteins; its inhibition negatively regulates separation and can overcome taxane resistance [4,5].
How does TRIM37 affect centrosome separation?
TRIM37 overexpression impairs centrosome separation, leading to centrosome dysfunction in 17q23-amplified breast cancer; targeting TRIM37 restores separation.
What is the link between BubR1 and centrosome separation?
BubR1 localizes to centrosomes and suppresses centrosome amplification by regulating Plk1 activity, thus negatively regulating separation.
Conclusion
The negative regulation of mitotic centrosome separation (GO:0046603) is a critical process for mitotic fidelity, ensuring that centrosomes separate only when appropriate. Dysregulation leads to centrosome amplification and aneuploidy, contributing to cancer and chemoresistance. Key regulators such as NEK2, BubR1, separase, and TRIM37 offer promising therapeutic targets. Continued research using CRISPR and advanced imaging will further elucidate the mechanisms and enable the development of targeted therapies.
References
- 1. Yeow ZY et al.. 2020. Targeting TRIM37-driven centrosome dysfunction in 17q23-amplified breast cancer.. Nature 585(7825):447-452 PMID: 32908313
- 2. Dementyeva E et al.. 2013. Clinical implication of centrosome amplification and expression of centrosomal functional genes in multiple myeloma.. J Transl Med 11:77 PMID: 23522059
- 3. Haaß W et al.. 2012. The proteolytic activity of separase in BCR-ABL-positive cells is increased by imatinib.. PLoS One 7(8):e42863 PMID: 22870341
- 4. Cervenka I et al.. 2016. Dishevelled is a NEK2 kinase substrate controlling dynamics of centrosomal linker proteins.. Proc Natl Acad Sci U S A 113(33):9304-9 PMID: 27486244
- 5. Roberts MS et al.. 2020. LIN9 and NEK2 Are Core Regulators of Mitotic Fidelity That Can Be Therapeutically Targeted to Overcome Taxane Resistance.. Cancer Res 80(8):1693-1706 PMID: 32054769
- 6. de Castro Ferezin C et al.. 2022. Identification of biological pathways and processes regulated by NEK5 in breast epithelial cells via an integrated proteomic approach.. Cell Commun Signal 20(1):197 PMID: 36550548
- 7. Izumi H et al.. 2009. BubR1 localizes to centrosomes and suppresses centrosome amplification via regulating Plk1 activity in interphase cells.. Oncogene 28(31):2806-20 PMID: 19503101
- 8. Tsai YC et al.. 2009. A G-quadruplex stabilizer induces M-phase cell cycle arrest.. J Biol Chem 284(34):22535-43 PMID: 19531483
