CDK12 (Cyclin-Dependent Kinase 12) is a cyclin-dependent kinase that associates with cyclin K and phosphorylates the C-terminal domain of RNA polymerase II. CDK12 is essential for proper transcription of long genes, particularly those involved in neuronal function and DNA damage response. It has been implicated in neurodegenerative diseases and cancer.
| Symbol | CDK12 |
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| Full Name | Cyclin-Dependent Kinase 12 |
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| Chromosomal Location | 17q12 |
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| NCBI Gene ID | [51755](https://www.ncbi.nlm.nih.gov/gene/51755) |
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| OMIM | [616622](https://www.omim.org/entry/616622) |
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| Ensembl ID | ENSG00000167258 |
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| UniProt ID | [Q9NYV4](https://www.uniprot.org/uniprot/Q9NYV4) |
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| Associated Diseases | [Alzheimer's Disease](/diseases/alzheimers-disease), [Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis), [Cancer](/diseases/cancer) |
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CDK12 is a serine/threonine kinase that forms a complex with cyclin K to phosphorylate the C-terminal domain (CTD) of RNA polymerase II. This is crucial for proper transcription elongation and RNA processing.
- Kinase Domain: C-terminal serine/threonine kinase domain
- Cyclin-Binding Region: N-terminal region for cyclin K interaction
- RS-Rich Region: Arginine-serine rich region involved in RNA processing
- Transcription Elongation: Promotes transcription through RNA Pol II pause sites
- RNA Processing: Coordinates co-transcriptional splicing and polyadenylation
- DNA Damage Response: Essential for transcription of DNA repair genes
- Neuroprotection: Maintains expression of neuronal survival genes
- Synaptic Function: Regulates genes important for synaptic plasticity
CDK12 has emerged as a significant player in ALS pathogenesis:
Long gene expression requirement:
- Motor neurons have exceptionally high requirements for long gene expression
- CDK12 is essential for maintaining expression of genes >100 kb
- Loss of CDK12 function leads to specific vulnerability of motor neurons
TDP-43 pathology interaction:
- TDP-43 proteinopathy, the hallmark of ALS, affects CDK12 regulation
- Disruption of this interaction leads to transcriptional dysregulation
- CDK12 dysfunction exacerbates TDP-43 pathology
DNA damage vulnerability:
- Motor neurons are particularly vulnerable to DNA damage
- CDK12-regulated genes include critical DNA repair factors
- Loss of CDK12 function impairs DNA repair capacity
CDK12 dysfunction contributes to Alzheimer's disease through multiple mechanisms:
Transcriptional dysregulation:
- CDK12 expression and activity altered in AD brain
- Impaired transcription of synaptic plasticity genes
- Dysregulation of neuronal survival pathways
Long gene vulnerability:
- Genes involved in synaptic function are preferentially affected
- Synaptic proteins with long transcripts show reduced expression
- Contributes to synaptic dysfunction in AD
CDK12 is a critical regulator of the DNA damage response:
Transcription of repair genes:
- Essential for expression of BRCA1, BRCA2, and other DNA repair factors
- Maintains genome stability in post-mitotic neurons
- Loss of CDK12 leads to accumulation of DNA lesions
CDK12 controls transcription through:
- Promoter-proximal pausing release
- Co-transcriptional RNA processing
- Chromatin regulation via the super elongation complex
- Transcriptional Dysregulation: CDK12 dysfunction may contribute to AD-related gene expression changes
- DNA Repair: Impaired DNA repair due to CDK12 deficiency may increase neuronal vulnerability
- Reference: Cheng et al., Nat. Neurosci. (2012)
- Oncogenic Role: CDK12 is frequently amplified or mutated in cancers
- Promotes Tumor Growth: Drives expression of growth-promoting genes
- Reference: Joshi et al., Cancer Cell (2013)
- Cerebral Cortex: High expression in pyramidal neurons
- Hippocampus: Expressed in all CA regions
- Motor Cortex: High expression in upper motor neurons
- Spinal Cord: Present in motor neurons
- Cerebellum: Moderate expression
- Nuclear: Primarily nuclear localization
- Nucleoplasmic: Distributed throughout nucleus
- Chromatin-Bound: Associates with chromatin during transcription
| Variant |
Function |
Disease Association |
| G1065E |
Missense |
Cancer somatic mutation |
| R1021H |
Missense |
Possible altered activity |
| G879S |
Polymorphism |
None confirmed |
- CDK12 Inhibitors: Being developed for cancer therapy (e.g., THZ531)
- Selectivity Challenge: Inhibitors may affect normal transcription
- Reference: Kwiatkowski et al., Nature (2014)
- Chemical Inhibitors: THZ531, SR-4835
- CRISPR/Cas9: Gene editing tools for CDK12