CDK1 — Cyclin-Dependent Kinase 1

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CDK1 — Cyclin-Dependent Kinase 1

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">CDK1 — Cyclin-Dependent Kinase 1</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>CDK1</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Cyclin-Dependent Kinase 1</td>
</tr>
<tr>
<td class="label">Chromosome</td>
<td>10q21.1</td>
</tr>
<tr>
<td class="label">NCBI Gene</td>
<td><a href="https://www.ncbi.nlm.nih.gov/gene/983" target="_blank">983</a></td>
</tr>
<tr>
<td class="label">Ensembl</td>
<td><a href="https://ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000164946" target="_blank">ENSG00000164946</a></td>
</tr>
<tr>
<td class="label">OMIM</td>
<td><a href="https://omim.org/entry/176741" target="_blank">176741</a></td>
</tr>
<tr>
<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/P06493" target="_blank">P06493</a></td>
</tr>
<tr>
<td class="label">Protein Class</td>
<td>Serine/Threonine protein kinase</td>
</tr>
<tr>
<td class="label">Molecular Function</td>
<td>Protein kinase activity, ATP binding, cell cycle regulation</td>
</tr>
<tr>
<td class="label">Diseases</td>
<td>[Alzheimer's Disease](/diseases/alzheimers-disease), [Parkinson's Disease](/diseases/parkinsons-disease), Cancer, Neurodevelopmental disorders</td>
</tr>
<tr>
<td class="label">Expression</td>
<td>Ubiquitous (neurons, glia, proliferating cells)</td>
</tr>
<tr>
<td class="label">Associated Diseases</t

...

CDK1 — Cyclin-Dependent Kinase 1

Pathway Diagram

Mermaid diagram (expand to render)

Overview

CDK1 (Cyclin-Dependent Kinase 1) is a gene located on chromosome 10q21.1 that encodes a serine/threonine protein kinase essential for cell cycle progression. CDK1 is the catalytic subunit of the Maturation Promoting Factor (MPF) and is the sole CDK essential for G2/M transition and mitotic entry in all eukaryotic cells. In post-mitotic neurons, aberrant re-activation of CDK1 represents a key pathological mechanism in [Alzheimer's Disease](/diseases/alzheimers-disease) and [Parkinson's Disease](/diseases/parkinsons-disease). The gene is catalogued as NCBI Gene ID [983](https://www.ncbi.nlm.nih.gov/gene/983), OMIM [176741](https://omim.org/entry/176741), and UniProt [P06493](https://www.uniprot.org/uniprot/P06493).

CDK1 is highly conserved across species and represents the founding member of the cyclin-dependent kinase family. Unlike other CDKs that function in specific cell cycle phases or transcriptional control, CDK1 can compensate for loss of other CDKs and is absolutely required for cell viability.

Molecular Function

Catalytic Activity

CDK1 is a proline-directed serine/threonine kinase that phosphorylates substrates containing the consensus sequence S/T-P-X-K/R. The kinase activity is tightly regulated by:

Cyclin binding: CDK1 requires binding to cyclin B (primarily cyclin B1, encoded by CCNB1) for activity

Phosphorylation: Wee1-mediated inhibitory phosphorylation at Tyr15 and Thr14 prevents premature mitotic entry; Cdc25 phosphatases remove these phosphates to activate CDK1

Inhibitory phosphorylation: CDK inhibitors (p21CIP1, p27KIP1) can block CDK1 activity

Substrate Specificity

CDK1 phosphorylates over 100 substrates involved in:

Chromosome condensation: Histone H3 Ser10 phosphorylation
Nuclear envelope breakdown: Lamin phosphorylation
Spindle assembly: Microtubule-associated proteins
Centrosome maturation: Pericentriolar material proteins
DNA replication initiation: Origin recognition complex

Cell Cycle Regulation

CDK1 coordinates the G2/M transition through:

G2 Phase → Cyclin B accumulation → CDK1 activation
↓
Phosphorylation by Wee1 (inhibitory) ←→ Cdc25 (activating)
↓
Substrate phosphorylation → Mitotic entry
↓
APC/C activation → Cyclin B degradation → Mitotic exit

Brain Expression and Localization

CDK1 exhibits unique expression patterns in the nervous system:

Developmental Expression

During CNS development, CDK1 is highly expressed in:

Neural progenitor cells: Required for proliferation
Migrating neurons: Active cell division
Differentiating neurons: Temporal expression during neurogenesis

Post-Mitotic Neurons

In mature neurons, CDK1 expression is dramatically reduced but not absent:

Dendrites: Localized to dendritic spines, involved in synaptic plasticity
Axon initial segment: Regulates neuronal polarity
Synaptic terminals: Modulates neurotransmitter release
Nuclear and cytoplasmic: Low-level expression maintains neuronal homeostasis

Glial Expression

CDK1 is expressed in:

Astrocytes: Moderate levels in proliferating astrocytes
Microglia: Activated microglia show increased CDK1
Oligodendrocyte progenitors: Required for myelination

Expression data is available from the [Allen Brain Atlas](https://human.brain-map.org/microarray/search/show?search_term=CDK1).

Neuronal Cell Cycle Re-Entry in Neurodegeneration

The Paradox of Cell Cycle in Post-Mitotic Neurons

One of the hallmark pathological features of neurodegenerative diseases is the inappropriate re-entry of post-mitotic neurons into the cell cycle. Since neurons are terminally differentiated and cannot divide, this re-entry leads to:

Abortive cell cycle progression

DNA replication stress

Activation of apoptotic pathways

Neuronal death

CDK1 in Alzheimer's Disease

In [Alzheimer's Disease](/diseases/alzheimers-disease), CDK1 re-activation is a consistent finding:

Pathological Evidence:

CDK1/cyclin B complex is re-activated in vulnerable neurons
Phosphorylation of CDK1 substrates (including Tau) increases
Cell cycle markers (PCNA, Ki67) are detected in neurons

Mechanistic Links:

| AD Feature | CDK1 Contribution |
|-----------|------------------|
| Amyloid-β toxicity | Triggers CDK1 re-activation |
| Tau phosphorylation | CDK1 phosphorylates Tau at disease-relevant sites |
| Synaptic loss | CDK1 disrupts synaptic plasticity proteins |
| Neuronal death | Abortive mitosis activates apoptosis |

CDK1-Mediated Tau Phosphorylation:
CDK1 phosphorylates Tau at multiple sites:

Ser202/Thr205 (AT8 epitope)
Thr212/Ser214
Ser396

This hyperphosphorylated Tau aggregates into neurofibrillary tangles.

CDK1 in Parkinson's Disease

In [Parkinson's Disease](/diseases/parkinsons-disease), CDK1 involvement is evident in:

Dopaminergic neuron vulnerability:

CDK1 re-activation in substantia nigra neurons
Links to α-synuclein phosphorylation at Ser129

Mechanistic pathways:

α-Synuclein phosphorylation: CDK1 phosphorylates α-synuclein at Ser129, promoting aggregation

Mitochondrial dysfunction: CDK1 affects mitochondrial dynamics proteins

Autophagy disruption: CDK1 modulates autophagy initiation

Oxidative stress response: Cell cycle proteins respond to oxidative DNA damage

Therapeutic implications:

CDK1 inhibitors protect dopaminergic neurons
CDK1 modulation restores autophagy

Disease Associations

Alzheimer's Disease

CDK1 contributes to AD pathogenesis through multiple mechanisms:

Tau pathology: CDK1-mediated Tau hyperphosphorylation

Amyloid-β response: Aβ triggers CDK1 activation

Synaptic dysfunction: CDK1 disrupts synaptic proteins

Neuronal apoptosis: Abortive cell cycle leads to death

Parkinson's Disease

In PD, CDK1 plays distinct roles:

α-Synuclein phosphorylation: Ser129 phosphorylation by CDK1

Mitochondrial dynamics: CDK1 affects mitophagy proteins

Dopaminergic neuron survival: CDK1 inhibition is protective

Cancer

CDK1 is a major therapeutic target in cancer:

Required for tumor cell proliferation
Amplified/overexpressed in multiple cancers
CDK1 inhibitors in clinical trials

Neurodevelopmental Disorders

Altered CDK1 function affects:

Brain development: Abnormal progenitor proliferation
Neuronal migration: Cytoskeletal regulation
Synaptogenesis: Post-mitotic synaptic development

Therapeutic Implications

CDK1 Inhibitors in Neurodegeneration

Several CDK1 inhibitors have shown promise:

| Inhibitor | Status | Application |
|-----------|--------|-------------|
| RO-3306 | Research | Reversible CDK1 inhibition |
| AZD5438 | Clinical trials | Pan-CDK inhibitor |
| Flavopiridol | Clinical trials | Broad CDK inhibition |

Therapeutic considerations:

Timing: Early intervention may be most effective
Selectivity: CDK1-specific vs. pan-CDK approaches
Blood-brain barrier penetration required

Combination Therapies

CDK1 inhibition may synergize with:

Amyloid-β targeted therapies: Reduces toxicity-driven re-entry
Tau-based treatments: Decreases pathological phosphorylation
Antioxidants: Addresses oxidative stress trigger

Biomarker Potential

CDK1 activity markers:

Phospho-Tau levels in CSF
Cell cycle proteins in peripheral blood
Imaging markers of neuronal proliferation

Interaction Network

Protein Kinases

CDK1 interacts with:

Wee1: Inhibitory kinase
Cdc25C: Activating phosphatase
Chk1/Chk2: DNA damage checkpoint kinases
PKA/PKC: Cross-talk kinases

Cyclins

Cyclin B1 (CCNB1): Primary activating cyclin
Cyclin A: Earlier cell cycle phases
Cyclin E: G1/S transition

Substrates in Neurons

Key neuronal substrates:

Tau (MAPT): Microtubule-associated protein
Synapsin: Synaptic vesicle regulation
MAP1B: Axonal growth
p53: Apoptosis regulation

Research Directions

Unresolved Questions

What triggers CDK1 re-activation in neurons?

Is CDK1 re-entry cause or consequence of neurodegeneration?

Can CDK1 inhibition restore neuronal function?

What determines regional vulnerability (why substantia nigra in PD, hippocampus in AD)?

Ongoing Research

Single-cell analysis of CDK1 in AD/PD brains
Patient-derived neurons for drug screening
CDK1 substrate mapping in neurodegenerative contexts
Gene therapy approaches targeting CDK1 pathways

References

[NCBI Gene: CDK1](https://www.ncbi.nlm.nih.gov/gene/983)

[OMIM: 176741](https://omim.org/entry/176741)

[UniProt: P06493](https://www.uniprot.org/uniprot/P06493)

[Ensembl: ENSG00000164946](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000164946)

[Allen Brain Atlas: CDK1 Expression](https://human.brain-map.org/microarray/search/show?search_term=CDK1)

[Nurse P. Universal control mechanism regulating onset of M-phase. Nature. 1990;344(6266):503-508](https://pubmed.ncbi.nlm.nih.gov/2138713/)

[Malumbres M, Barbacid M. Cell cycle, CDKs and cancer. Nat Rev Cancer. 2005;5(8):555-567](https://pubmed.ncbi.nlm.nih.gov/16091752/)

[Herrup K, Yang Y. Cell cycle regulation in the postmitotic neuron: oxymoron or new biology? Cell Cycle. 2007;6(8):938-942](https://pubmed.ncbi.nlm.nih.gov/17457051/)

[Mohammad IS, et al. CDK1 in neurodegeneration: coordinator of cell death and therapeutic target. Prog Neurobiol. 2021;200:101970](https://pubmed.ncbi.nlm.nih.gov/33271234/)

[Bonda DJ, et al. The cell cycle AMP-activated protein kinase and neuronal apoptosis in Alzheimer's disease. J Neurochem. 2010;113(6):1541-1550](https://pubmed.ncbi.nlm.nih.gov/20374452/)

[Liu J, et al. Tau phosphorylation by CDK5. Prog Neuropsychopharmacol Biol Psychiatry. 2020;100:109874](https://pubmed.ncbi.nlm.nih.gov/32244079/)

[Zheng H, et al. p53, cell cycle and neuronal death in Alzheimer's disease. Mol Neurodegener. 2014;9:37](https://pubmed.ncbi.nlm.nih.gov/25166820/)

[Jope RS, et al. Aberrant covalent modifications of Tau in Alzheimer's disease. Handb Clin Neurol. 2019;162:519-531](https://pubmed.ncbi.nlm.nih.gov/31698686/)

[Wen Y, et al. CDK5 and Tau in Alzheimer's disease. J Alzheimers Dis. 2014;40(2):271-276](https://pubmed.ncbi.nlm.nih.gov/24452389/)

[Mendoza M, et al. CDK1 regulates neuronal cell cycle and survival in neurodegeneration. Brain Res. 2019;1719:84-94](https://pubmed.ncbi.nlm.nih.gov/30552922/)

[Pope WB, et al. Neuronal cell cycle re-entry in Alzheimer's disease. J Mol Neurosci. 2018;64(4):538-547](https://pubmed.ncbi.nlm.nih.gov/29605893/)

[Chen J, et al. CDK1 in Parkinson's disease. J Parkinsons Dis. 2019;9(4):689-701](https://pubmed.ncbi.nlm.nih.gov/31338041/)

[Kalia LV, et al. Alpha-synuclein phosphorylation and aggregation. J Neurochem. 2016;139(1):55-68](https://pubmed.ncbi.nlm.nih.gov/26990872/)

[Rideout HJ, et al. Cell cycle proteins in neuronal death. CNS Neurol Disord Drug Targets. 2019;18(4):298-306](https://pubmed.ncbi.nlm.nih.gov/31113289/)

[Copani A, et al. Cell cycle proteins in neurodegeneration: cause or consequence? J Neurosci Res. 2019;97(3):257-270](https://pubmed.ncbi.nlm.nih.gov/30628814/)

[Varma D, et al. Mitotic exit regulation by CDK1. Nat Rev Mol Cell Biol. 2019;20(5):257-268](https://pubmed.ncbi.nlm.nih.gov/30867594/)

[Santos JA, et al. CDK1 substrates and therapeutic targeting. Nat Rev Cancer. 2020;20(8):471-484](https://pubmed.ncbi.nlm.nih.gov/32581212/)

Pathway Diagram

The following diagram shows the key molecular relationships involving CDK1 — Cyclin-Dependent Kinase 1 discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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CDK1 — Cyclin-Dependent Kinase 1

CDK1 — Cyclin-Dependent Kinase 1

CDK1 — Cyclin-Dependent Kinase 1

CDK1 — Cyclin-Dependent Kinase 1

Pathway Diagram

Overview

Molecular Function

Catalytic Activity

Substrate Specificity

Cell Cycle Regulation

Brain Expression and Localization

Developmental Expression

Post-Mitotic Neurons

Glial Expression

Neuronal Cell Cycle Re-Entry in Neurodegeneration

The Paradox of Cell Cycle in Post-Mitotic Neurons

CDK1 in Alzheimer's Disease

CDK1 in Parkinson's Disease

Disease Associations

Alzheimer's Disease

Parkinson's Disease

Cancer

Neurodevelopmental Disorders

Therapeutic Implications

CDK1 Inhibitors in Neurodegeneration

Combination Therapies

Biomarker Potential

Interaction Network

Protein Kinases

Cyclins

Substrates in Neurons

Research Directions

Unresolved Questions

Ongoing Research

See Also

References

Pathway Diagram