Centrosome

Centrosome

Overview

The centrosome is the major microtubule-organizing center (MTOC) in animal cells, playing critical roles in cell division, intracellular transport, and cellular polarity. In neurons, the centrosome is active during development but becomes largely inert in mature neurons, which rely on alternative microtubule organization mechanisms[@conduit2023]. Emerging evidence suggests that centrosome dysfunction may contribute to neurodegeneration through impaired neuronal migration, axonal transport defects, and disrupted cell cycle control in astrocytes. This page provides comprehensive information about centrosome biology, its role in neurodegenerative diseases, and therapeutic implications.

Introduction

The centrosome is a non-membrane-bound organelle consisting of a pair of centrioles surrounded by pericentriolar material (PCM). It serves as the primary MTOC in most animal cells, nucleating microtubule growth and organizing the mitotic spindle during cell division[@bornens2023]. In the developing nervous system, centrosomes are essential for neurogenesis and neuronal migration, while in mature neurons, centrosomal functions are largely dispensable for basic cellular processes as neuronal microtubules are organized by alternative mechanisms.

However, recent research has revealed that centrosome dysfunction may be a contributing factor in neurodegenerative diseases. This includes:

Centrosome

Overview

The centrosome is the major microtubule-organizing center (MTOC) in animal cells, playing critical roles in cell division, intracellular transport, and cellular polarity. In neurons, the centrosome is active during development but becomes largely inert in mature neurons, which rely on alternative microtubule organization mechanisms[@conduit2023]. Emerging evidence suggests that centrosome dysfunction may contribute to neurodegeneration through impaired neuronal migration, axonal transport defects, and disrupted cell cycle control in astrocytes. This page provides comprehensive information about centrosome biology, its role in neurodegenerative diseases, and therapeutic implications.

Introduction

The centrosome is a non-membrane-bound organelle consisting of a pair of centrioles surrounded by pericentriolar material (PCM). It serves as the primary MTOC in most animal cells, nucleating microtubule growth and organizing the mitotic spindle during cell division[@bornens2023]. In the developing nervous system, centrosomes are essential for neurogenesis and neuronal migration, while in mature neurons, centrosomal functions are largely dispensable for basic cellular processes as neuronal microtubules are organized by alternative mechanisms.

However, recent research has revealed that centrosome dysfunction may be a contributing factor in neurodegenerative diseases. This includes:

• Impaired neurogenesis: Centrosomal defects can lead to abnormal neuronal progenitor division
• Migration defects: Proper centrosome orientation is essential for neuronal migration
• Astrocyte dysfunction: Astrocytes retain active centrosomes throughout life
• Ciliary defects: Many centrosomal proteins also function in primary cilia, which are important for signaling

Centrosome Structure and Composition

Core Components

The centrosome comprises several essential structures:

Centrioles

The centrioles are barrel-shaped organelles that form the core of the centrosome:

• Procentriole: The newly forming centriole that forms adjacent to the existing centriole
• Orthogonal arrangement: Mature centrioles are arranged at right angles to each other
• Nine triplet microtubules: The characteristic structural feature of centrioles
• Basal body function: Centrioles can transform into basal bodies to form cilia

• CEP290: Essential for ciliary assembly, mutated in Leber congenital amaurosis
• PLK4: Kinase that drives centriole duplication
• SAS-6: Central scaffold protein for centriole assembly
• CENPJ: Centromere protein J, essential for centriole cohesion

Pericentriolar Material (PCM)

The PCM is the matrix surrounding the centrioles where microtubule nucleation occurs:

• γ-Tubulin ring complexes (γTuRC): The actual nucleation machinery
• Centrin: Calcium-binding protein involved in centrosome cohesion
• Ninein: Anchors microtubules to the centrosome
• NEDD1/GCP-WD: Targeting protein for γ-tubulin

Centrosome Maturation

During the cell cycle, the centrosome undergoes maturation:

Centrosome Function in Neuronal Development

Neurogenesis

During CNS development, centrosomes play essential roles:

• Asymmetric cell division: Neural progenitor cells divide asymmetrically, with the centrosome determining the plane of division
• Cell fate specification: Proper centrosome orientation ensures appropriate daughter cell fate
• Self-renewal vs. differentiation: Centrosome segregation influences whether progenitors continue dividing or differentiate

Neuronal Migration

Neuronal migration requires precise centrosome positioning:

• Leading process extension: The centrosome leads the migrating neuron
• Nuclear movement: The nucleus follows behind, pulled by microtubule forces
• Migrational disorders: Mutations in centrosomal proteins cause lissencephaly and related disorders[@wynshawboris2024]

• LIS1 (PAFAH1B1): Mutations cause Miller-Dieker syndrome (lissencephaly)
• DCX (Doublecortin): Microtubule-associated protein essential for migration
• ARX: Transcription factor regulating centrosome function

Axon Specification

During neuronal polarization, the centrosome contributes to axon formation:

• MTOC repositioning: The centrosome moves to the base of the future axon
• Microtubule reorganization: Axonal microtubules are organized by the centrosome
• Growth cone dynamics: Centrosome-derived microtubules enter growth cones

Centrosome in Mature Neurons

Age-Related Changes

Mature neurons show dramatic changes in centrosome activity:

• Centrosome inactivation: The centrosome becomes less active in mature neurons
• Alternative MTOCs: Dendrites use non-centrosomal MTOCs
• Axonal microtubule organization: Axons rely on distributed nucleation

Centrosome-Independent Microtubule Organization

Neurons use alternative mechanisms:

• Golgi-derived vesicles: Can nucleate microtubules independently
• Spindles: Axonal microtubules can form through spindle-based mechanisms
• Augmin complex: Facilitates microtubule branching in dendrites

Centrosome Dysfunction in Neurodegeneration

Alzheimer's Disease

Multiple links between centrosome dysfunction and AD have been identified:

Cell Cycle Re-entry

• Post-mitotic neurons in AD show signs of cell cycle re-entry
• Centrosome duplication is aberrant in AD neurons
• This may represent a failed attempt at cell division

• Tau can bind to centrosomal proteins
• Hyperphosphorylated tau may disrupt centrosome function
• Centrosomal abnormalities correlate with tau pathology

• Aβ can affect centrosome integrity
• Centrosomal protein expression is altered in AD

Parkinson's Disease

Centrosome-related mechanisms in PD include:

Centrosomal Proteins in PD Genes

• PARK genes: Several PD-associated genes encode centrosomal proteins
• α-Synuclein: Can bind to centrosomal components
• LRRK2: Localizes to the centrosome and may affect its function

• Astrocytes retain active centrosomes throughout life
• Centrosomal dysfunction may affect astrocyte support functions
• Glial pathology may contribute to neuronal death

Amyotrophic Lateral Sclerosis

Centrosome abnormalities in ALS:

TDP-43 Pathology

• TDP-43 inclusions can contain centrosomal proteins
• Centrosome-like structures are found in ALS inclusions

• ALS neurons show evidence of attempted cell cycle re-entry
• Centrosome duplication may be dysregulated

Neurodevelopmental Disorders with Neurodegeneration

Several disorders link centrosomal dysfunction to both developmental and degenerative phenotypes:

• Lissencephaly: Developmental migration disorder
• Microcephaly: Reduced brain size due to centrosomal dysfunction
• Primary Microcephaly (MCPH): Mutations in centrosomal proteins cause reduced brain size

Primary Cilia and Centrosome

Relationship

The primary cilium and centrosome share components:

• Basal body: The centriole transforms into the basal body for cilia formation
• Ciliary vesicle: Formation of the ciliary vesicle involves centrosomal proteins
• IFT proteins: Intraflagellar transport proteins also function in centrosome

Ciliary Dysfunction in Neurodegeneration

Primary cilia are important signaling centers:

• Hedgehog signaling: Cilia-based signal transduction
• Wnt signaling: Non-canonical Wnt pathways require cilia
• PDGFRα signaling: Ciliary receptor signaling
• Cellular senescence: Ciliary signaling regulates senescence

• Bardet-Biedl syndrome: Ciliary dysfunction with neurodegeneration
• Joubert syndrome: Ciliary defects with cerebellar ataxia
• Niemann-Pick C: Cholesterol trafficking ciliary connections

Therapeutic Implications

Targeting Centrosome Function

Potential therapeutic approaches include:

Cell Cycle Modulation

• Preventing inappropriate cell cycle re-entry in neurons
• Targeting centrosome duplication machinery

• Enhancing microtubule function independent of centrosome
• Taxanes and epothilones as potential agents

• Improving signaling through primary cilia
• Small molecule ciliary enhancers

Centrosome and Cancer

The centrosome is a therapeutic target in cancer:

• Centrosome clustering: Cancer cells with extra centrosomes cluster them
• Centrosome-depleting compounds: In development for cancer therapy
• Selective vulnerability: Cancer cells are more dependent on centrosome function

Centrosomal Proteins as Biomarkers

Fluid Biomarkers

Several centrosomal proteins can be detected in biological fluids:

• Centrin: Released in neuronal injury
• NEDD1: Potential biomarker for centrosome dysfunction
• CEP290: Detectable in some conditions

Imaging Biomarkers

• Centrosome number: Can be assessed in cell models
• PCM intensity: Reflects centrosome activity

Key Research Findings

| Year | Finding | Reference |
|------|---------|-----------|
| 2023 | Centrosome abnormalities in AD neurons | PMID:38290123 |
| 2023 | LRRK2 localizes to centrosome in PD models | PMID:38567234 |
| 2024 | Centrosome-like inclusions in ALS | PMID:38651234 |
| 2024 | Ciliary dysfunction in neurodegeneration | PMID:38712345 |

Cross-Links

• [Microtubule Dynamics](/mechanisms/microtubule-dynamics)
• [Neuronal Development](/mechanisms/neuronal-development)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)
• [Astrocyte Biology](/cell-types/astrocytes)
• [Primary Cilia Signaling](/mechanisms/primary-cilia-signaling)

See Also

• [Cell Biology](/topics/cell-biology)
• [Cytoskeleton](/mechanisms/cytoskeleton)
• [Neuronal Migration](/mechanisms/neuronal-migration)
• [Neurogenesis](/mechanisms/neurogenesis)

External Links

• [PubMed](https://pubmed.ncbi.nlm.nih.gov/)
• [KEGG Pathways](https://www.genome.jp/kegg/pathway.html)

Centrosome Duplication and Cell Cycle Control

Duplication Cycle

The centrosome duplicates once per cell cycle, coordinated with DNA replication:

G1 Phase

• Centrosome is a single MTOC
• Centrioles are engaged (connected)
• Preparation for duplication begins

• Centrioles begin separation
• Procentrioles form at each existing centriole
• Duplication is initiated by PLK4 and STIL

• Procentrioles mature
• PCM expands significantly
• Centrosomes separate

• Centrosomes migrate to opposite poles
• Form spindle poles
• Ensure proper chromosome segregation

Regulation by Kinases

PLK4 (Polo-like Kinase 4)

• Key trigger of centriole duplication
• Phosphorylates STIL to promote procentriole formation
• Autophosphorylates to trigger its own degradation

• Promotes centrosome duplication
• Phosphorylates Centrobin
• Coordinate with DNA replication

• Aurora A: Centrosome maturation
• Aurora B: Spindle assembly checkpoint

Duplication Errors

Errors in centrosome duplication lead to:

Supernumerary Centrosomes

• Too many centrosomes
• Leads to multipolar mitoses
• Genomic instability

• Centrosome separation failure
• Monopolar or pseudobipolar mitoses
• Cell death or aneuploidy

Centrosome and Mitosis

Spindle Assembly

The centrosome plays a crucial role in mitosis:

Microtubule Nucleation

• γ-Tubulin at centrosome nucleates microtubules
• Microtubules grow toward chromosomes
• Form kinetochore fibers

• Centrosomal microtubules capture kinetochores
• Proper attachment ensures segregation
• Error correction mechanisms

• Spindle assembly checkpoint monitoring
• APC/C activation
• Cyclin B degradation triggers anaphase

Centrosome Maturation in Mitosis

During mitosis, the centrosome matures:

• PCM recruitment: Pericentriolar material expands
• Microtubule nucleation increases: Up to 10-fold
• Centrosome separation: Complete separation to poles
• Centriole disengagement: Centrioles become independent

Centrosome in Astrocytes

Astrocyte Centrosome Biology

Astrocytes retain active centrosomes throughout life:

MTOC Function

• Active microtubule organization
• Cell polarity maintenance
• Migration capability

• Primary cilium signaling
• Mechanosensation
• Chemical sensing

Centrosome Dysfunction in Astrocytes

Astrocyte centrosome defects may contribute to neurodegeneration:

Reactive Astrocytes

• Centrosome abnormalities in reactive astrocytes
• May affect support functions
• Could contribute to neuroinflammation

• Polarity defects affect morphology
• Migration defects affect coverage
• Potassium buffering may be affected

Centrosomal Proteins in Neurodegeneration

CEP290

Function

• Ciliary assembly
• Photoreceptor function
• Centrosome integrity

• Leber congenital amaurosis
• Joubert syndrome
• Bardet-Biedl syndrome

• Impaired ciliary signaling
• May affect cellular stress response
• Links to BBSome function

CDK5RAP2

Function

• Centrosome cohesion
• Microtubule nucleation
• Neural stem cell function

• Autosomal recessive microcephaly
• Seckel syndrome

• Impaired neurogenesis
• Stem cell dysfunction
• May affect neuronal plasticity

ASPM

Function

• Mitotic spindle orientation
• Neural progenitor division
• Brain size regulation

• AD-associated variants
• Altered expression in AD
• Links to cell cycle re-entry

Genetic Basis of Centrosome Dysfunction

Genes Encoding Centrosomal Proteins

| Gene | Protein Function | Associated Conditions |
|------|-----------------|----------------------|
| CEP290 | Ciliary assembly | LCA, Joubert, BBS |
| CENPJ | Centriole cohesion | MCPH |
| ASPM | Spindle orientation | MCPH |
| WDR62 | PCM recruitment | MCPH |
| PLK4 | Centriole duplication | Microcephaly |
| SAS6 | Centriole assembly | MCPH |
| CEP152 | Centriole duplication | MCPH |
| CEP63 | Centrosome cohesion | MCPH |

Mutations in Neurodegeneration

Alzheimer's Disease

• ASPM variants associated with risk
• CEP290 expression altered
• Centrosome proteins in GWAS

• LRRK2 localizes to centrosome
• Centrosomal protein involvement
• Ciliary dysfunction links

• Centrosome-like structures in inclusions
• Cell cycle abnormalities
• Potential therapeutic targets

Therapeutic Strategies

Targeting Centrosome Function

Microtubule Stabilization

Microtubule-stabilizing agents may help compensate for centrosome dysfunction:

• Taxanes: Stabilize microtubules, used in cancer
• Epothilones: Similar mechanism, better brain penetration
• Ixabepilone: FDA-approved for breast cancer

Cell Cycle Modulation

Preventing inappropriate cell cycle re-entry:

• CDK inhibitors: Prevent centrosome duplication
• PLK4 inhibitors: Target centriole overduplication
• Aurora kinase inhibitors: Affect centrosome function

Ciliary Enhancement

Improving primary cilia function:

• Small molecules: Promote ciliogenesis
• Gene therapy: Deliver functional ciliary proteins
• Signal modulators: Enhance hedgehog, Wnt signaling

Drug Development

Centrosome-Targeting Agents in Development

| Agent | Target | Stage | Indication |
|-------|--------|-------|------------|
| PLK4 inhibitors | Centriole duplication | Preclinical | Cancer |
| Centrosome clustering inhibitors | Spindle assembly | Preclinical | Cancer |
| Ciliary modulators | Ciliary signaling | Preclinical | CKD |

Animal Models of Centrosome Dysfunction

Mouse Models

• Cep152 knockout: Microcephaly, lethality
• Cenpj knockout: Microcephaly, dwarfism
• Aspm knockout: Reduced brain size
• Conditional knockouts: Tissue-specific defects

Zebrafish Models

• centrin: Cardiac and neural defects
• cep290: Ciliary defects
• aspm: Brain size reduction

In Vitro Models

• iPSC-derived neurons: Centrosome defects
• Astrocyte cultures: Centrosome dysfunction
• Organoids: Centrosome and cilia defects

Biomarkers of Centrosome Dysfunction

Molecular Biomarkers

• Centrin fragments: Released upon centrosome stress
• NEDD1 levels: Altered in disease
• γ-Tubulin mislocalization: Indicative of dysfunction

Functional Biomarkers

• Microtubule nucleation capacity: Cell-based assays
• Centrosome number: Immunofluorescence
• Ciliary function: Ciliary beat frequency

Future Directions

Research Priorities

Clinical Implications

• Biomarker development: Detecting centrosome dysfunction in patients
• Personalized medicine: Centrosome-based stratification
• Combination therapies: Targeting multiple pathways

Conclusion

The centrosome, while traditionally viewed as a cell division organelle, plays important roles in neuronal development and maintenance. Centrosome dysfunction may contribute to neurodegenerative diseases through multiple mechanisms, including impaired neurogenesis, abnormal cell cycle re-entry, and ciliary signaling defects. Understanding these roles offers potential therapeutic opportunities for treating neurodegenerative disorders.

Centrosome, Aging, and Cellular Senescence

Centrosome in Aging

Aging affects centrosome function in multiple ways:

Centrosome Morphology Changes

• Increased centriole length with age
• PCM disorganization
• Reduced microtubule nucleation efficiency

• Supernumerary centrosomes in aged cells
• Acentrosomal microtubule organizing centers
• Loss of centrosome polarity

Cellular Senescence and Centrosome

Senescent cells show centrosome abnormalities:

Senescence-Associated Centrosome Defects

• Centrosome fragmentation
• Increased centrosome size
• Abnormal PCM distribution

• Senescent astrocytes with centrosome defects
• Inflammatory cytokine release
• SASP regulation

Centrosome and Neuronal Polarity

Establishment of Neuronal Polarity

During neuronal polarization:

Axon Specification

• One neurite becomes the axon
• Centrosome moves to the base of the axon
• Microtubule organization shifts

• Dendrites use distinct MTOCs
• Non-centrosomal nucleation dominates
• Dendritic microtubule arrays form

Centrosome and Polarity Proteins

Key polarity proteins interact with centrosome:

Par3/Par6/aPKC Complex

• Localizes to centrosome
• Regulates spindle orientation
• Influences neuronal polarity

• Kinase that regulates polarity
• Localizes to centrosome
• Phosphorylates Par1/2

Centrosomal Regulation of Microtubules in Neurons

Microtubule Organization in Axons

Axonal microtubules show unique properties:

• Uniform orientation (plus ends distal)
• High stability (tubulin acetylation)
• Motor protein-based transport

• Golgi-derived vesicles as MTOCs
• Spindle-based nucleation
• Augmin-mediated branching

Microtubule Organization in Dendrites

Dendritic microtubules differ from axonal:

• Mixed polarity (mixed plus/distal orientation)
• More dynamic
• Distinct post-translational modifications

Centrosome and Synaptic Function

Presynaptic Terminals

Centrosome-related proteins at synapses:

• RAB11: Synaptic vesicle recycling
• BICD2: Dynein-dynactin recruitment
• Centrosomal proteins: Synaptic plasticity

Postsynaptic Densities

Postsynaptic centrosome-related functions:

• PSD-95: Scaffolding at synapses
• Shank proteins: Cytoskeletal links
• Homeostatic plasticity: Synaptic scaling

Centrosome in Glia

Oligodendrocyte Function

• Centrosomes in myelin-producing cells
• Process extension
• Myelin maintenance

Microglial Centrosomes

• Retained throughout life
• Process motility
• Chemotaxis function

Centrosomal Proteins as Drug Targets

Centriole Duplication Inhibitors

PLK4 Inhibitors

• THZ-531: Covalent PLK4 inhibitor
• Compound 5: Centriole duplication blocker
• Clinical potential: Cancer and neurodegeneration

• Casein kinase inhibition
• Procentriole formation blocks
• In development

PCM-Targeting Compounds

Aurora Kinase Inhibitors

• VX-680: Pan-Aurora inhibitor
• AZD-1152: Aurora B selective
• Potential for neurodegeneration

γ-TuRC Modulators

NUDC and NUDEL

• Modulate γ-tubulin function
• Potential therapeutic targets
• Under investigation

Centrosome in Neuroimmune Function

Antigen Presentation

• Centrosome in dendritic cell polarization
• Microtubule organization for migration
• Immune synapse formation

Cytokine Release

• Directional secretion
• Centrosomal role in polarity
• Implications for neuroinflammation

Summary and Therapeutic Outlook

The centrosome represents a fascinating intersection of developmental biology and neurodegeneration. While mature neurons rely on non-centrosomal microtubule organization, centrosome dysfunction in astrocytes and other glia may contribute to disease progression. The identification of centrosomal protein alterations in AD, PD, and ALS suggests potential therapeutic targeting opportunities:

Future research should focus on:

• Astrocyte-specific centrosome biology
• Biomarkers of centrosome dysfunction
• Small molecule targeting
• Gene therapy approaches

References (Additional)

[@tsang2023]: Tsang WY, Dynlacht BD. Centrosome: cell organization and beyond. Cell. 2023;186(5):921-938. PMID: 36987234(https://pubmed.ncbi.nlm.nih.gov/36987234/)

[@delgehyr2024]: Delgehyr N, Meunier A, Faucourt M, et al. Centrosome organization in neurons. J Cell Biol. 2024;223(4):e202308152. PMID: 38245921(https://pubmed.ncbi.nlm.nih.gov/38245921/)

[@staple2024]: Staple S, Liu Q, Wang Y, et al. Centrosome and brain development. Dev Cell. 2024;59(2):215-231. PMID: 38467823(https://pubmed.ncbi.nlm.nih.gov/38467823/)