GTF2H3 Protein

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GTF2H3 Protein

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GTF2H3 Protein

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">GTF2H3 Protein</th>
</tr>
<tr>
<td class="label">Protein Name</td>
<td>General Transcription Factor IIH Subunit 3 (GTF2H3)</td>
</tr>
<tr>
<td class="label">Gene</td>
<td>[GTF2H3](/genes/gtf2h3)</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td>[Q13888](https://www.uniprot.org/uniprot/Q13888)</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~66 kDa (573 amino acids)</td>
</tr>
<tr>
<td class="label">Subcellular Localization</td>
<td>Nucleus (nuclear speckles, nucleoplasm)</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>TFIIH complex</td>
</tr>
<tr>
<td class="label">Aliases</td>
<td>TFIIH subunit p34, TFB3, CAK subunit</td>
</tr>
<tr>
<td class="label">Expression</td>
<td>Ubiquitous; highest in brain, liver, kidney</td>
</tr>
<tr>
<td class="label">Year</td>
<td>Finding</td>
</tr>
<tr>
<td class="label">2004</td>
<td>Crystal structure of TFIIH core complex</td>
</tr>
<tr>
<td class="label">2006</td>
<td>GTF2H3 role in transcription-repair coupling</td>
</tr>
<tr>
<td class="label">2011</td>
<td>NER defects in neurodegeneration</td>
</tr>
<tr>
<td class="label">2013</td>
<td>Cockayne syndrome RNA polymerase II</td>
</tr>
<tr>
<td class="label">2014</td>
<td>Activity-induced DNA breaks in neurons</td>
</tr>
<tr>
<td class="label">2015</td>
<td>Pol II transcription and DNA repair coupling</td>
</tr>
<tr>
<td class="label">2017</td>
<td>XPG and transcription stress</td>
</tr>
<tr>
<td class="label">2018</td>
<td>DNA damage and aging in the brain</td>
</tr>
<tr>
<td class="label">2019</td>
<td>DNA damage response in Alzheimer's disease</td>
</tr>
<tr>
<td class="label">2019</td>
<td>DNA repair gene expression in PD brain</td>
</tr>
<tr>
<td class="label">2019</td>
<td>TFIIH and neuronal differentiation</td>
</tr>
<tr>
<td class="label">2019</td>
<td>Oxidative stress and transcription in neurons</td>
</tr>
<tr>
<td class="label">2020</td>
<td>TFIIH phosphorylation in neuronal survival</td>
</tr>
<tr>
<td class="label">2024</td>
<td>TFIIH mutations in neurodegeneration</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

:: infobox .infobox-protein
::

Overview

General Transcription Factor IIH Subunit 3 (GTF2H3) is a core component of the TFIIH transcription factor complex, which is essential for RNA polymerase II (Pol II) transcription initiation and nucleotide excision repair (NER). GTF2H3 plays critical roles in maintaining genomic integrity in [neurons](/cell-types/neurons) and has been implicated in the pathogenesis of neurodegenerative diseases including [Alzheimer's disease](/diseases/alzheimers-disease), [Parkinson's disease](/diseases/parkinsons-disease), and [amyotrophic lateral sclerosis](/diseases/amyotrophic-lateral-sclerosis) [@ecoffet2024].

The TFIIH complex is a multifunctional protein complex consisting of multiple subunits that coordinate transcriptional regulation and DNA repair. GTF2H3 (also known as p34) contributes to the structural integrity and functional regulation of this complex [@schaerer2006]. Given the post-mitotic nature of neurons and their high metabolic activity, proper TFIIH function is critical for neuronal survival and stress resistance [@madabhushi2014].

Structure and Biochemistry

Protein Architecture

GTF2H3 is a 573-amino acid protein with a molecular weight of approximately 66 kDa. The protein adopts a fold that integrates into the TFIIH core, serving as a scaffold for the complex. Key structural features include:

N-terminal Domain: Interacts with the [XPB](/proteins/xpb-protein) subunit (ERCC3), establishing one of the primary interfaces within the TFIIH core
Central Scaffold Region: Binds [XPD](/proteins/xpd-protein) (ERCC2) and contributes to the structural integrity of the TFIIH ring
C-terminal Region: Involved in CAK submodule recruitment and regulatory interactions

The crystal structure of the TFIIH core revealed that GTF2H3 adopts an extended, elongated conformation that spans the central cavity of the complex, making contacts with multiple subunits simultaneously. This scaffolding role explains why GTF2H3 is essential for TFIIH stability—depletion or mutation of GTF2H3 leads to rapid degradation of the entire complex [@tfiih2004].

TFIIH Complex Organization

The TFIIH complex can be divided into two functional modules:

Core complex: Contains XPB, XPD, GTF2H3 (p34), GTF2H2 (p44), GTF2H5, and p52 - responsible for transcription initiation and NER

Kinase module: Contains CDK7, cyclin H, and MAT1 - responsible for Pol II CTD phosphorylation

GTF2H3 serves as a critical scaffold that stabilizes the core complex and facilitates proper positioning of the XPB and XPD helicases [@weinberg2015]. The integrity of this scaffold is essential for both transcriptional activation and NER efficiency.

Normal Physiological Function

Transcriptional Regulation

GTF2H3 is essential for RNA polymerase II transcription initiation. The TFIIH complex, including GTF2H3, is recruited to promoter regions by general transcription factors (TFIID, TFIIA, TFIIB) and facilitates promoter DNA unwinding through the XPB helicase activity [@tfiih2004]. GTF2H3 contributes to:

Promoter clearance: Stabilizing the open complex formation
Transcription elongation: Supporting efficient Pol II passage through gene bodies
Transcriptional coupling: Connecting transcription with RNA processing

Within the TFIIH complex, GTF2H3 participates in the transcription initiation process through:

Promoter Recognition: TFIIH is recruited to promoter regions by TFIID and other general transcription factors

DNA Unwinding: The XPB subunit of TFIIH has ATP-dependent helicase activity that unwinds the DNA duplex at the transcription start site, creating an open bubble

Promoter Clearance: Following initial transcript synthesis, TFIIH releases from the promoter to allow productive elongation

The CAK submodule (CDK7, Cyclin H, and MAT1) phosphorylates the RNA polymerase II C-terminal domain (CTD) at Ser5, marking the transition from initiation to elongation.

Nucleotide Excision Repair

GTF2H3 plays a central role in NER, the primary pathway for removing bulky DNA adducts including UV-induced pyrimidine dimers [@lehmann2011]. The NER pathway involves:

Damage recognition by XPC-RAD23B

TFIIH recruitment (including GTF2H3)

DNA unwinding by XPB/XPD helicases

Damage verification by XPA

Dual incision by XPG and XPF-ERCC1

DNA ligation

GTF2H3 is essential for TFIIH recruitment to damage sites and for maintaining the stability of the NER complex [@gtfh2006].

Expression in the Brain

In the central nervous system, GTF2H3 is expressed at high levels in:

Neurons: Particularly in hippocampal CA1 and cortical layer 5 pyramidal neurons
Glial Cells: Astrocytes and oligodendrocytes show moderate expression
Neural Progenitors: Required for proper neuronal differentiation

The high neuronal expression reflects the constant transcriptional demand of neurons and their need for DNA repair capacity.

Neuronal Specific Functions

In neurons, TFIIH and GTF2H3 have specialized functions due to the unique challenges of post-mitotic cells:

Activity-induced gene expression: Neuronal activity triggers rapid gene expression programs requiring TFIIH function
DNA repair capacity: Neurons accumulate DNA damage over time and rely on NER [@madabhushi2014]
Transcriptional stress response: TFIIH helps neurons respond to oxidative and metabolic stress [@hou2019]

Role in Neurodegenerative Diseases

Alzheimer's Disease

GTF2H3 dysfunction may contribute to multiple aspects of AD pathogenesis:

Transcriptional dysregulation: AD brains show widespread transcriptional alterations, including downregulation of synaptic genes and mitochondrial function genes. GTF2H3 impairment could contribute to this "transcriptional aging" phenotype by compromising the precision of RNA polymerase II initiation.

DNA repair deficiency: Neurons in AD exhibit accumulated DNA damage, including oxidative lesions and telomere attrition. Impaired NER due to GTF2H3 dysfunction would compound this deficit [@kats2019].

Tau pathology: TFIIH subunits interact with tau; pathological tau may disrupt transcription regulation.

Amyloid-β effects: Amyloid-β oligomers can induce oxidative stress and DNA damage in neurons. An intact GTF2H3-mediated NER pathway is essential for coping with this damage.

DNA damage accumulation is a hallmark of AD brains, and GTF2H3-mediated NER is critical for maintaining genomic integrity [@jiang2019].

Research has shown that Cockayne syndrome (CS) cells, which have TFIIH mutations, exhibit phenotypes reminiscent of neuronal aging, including accumulation of DNA damage, mitochondrial dysfunction, and transcriptional repression—processes central to AD pathogenesis [@egf2013].

Parkinson's Disease

In PD, GTF2H3 may contribute through several mechanisms:

Mitochondrial dysfunction: PD neurons face increased oxidative stress; DNA damage accumulates

α-Synuclein transcription regulation: The SNCA gene encoding alpha-synuclein is under complex transcriptional control. TFIIH is required for proper SNCA expression regulation, and altered TFIIH function could contribute to dysregulated alpha-synuclein expression.

Oxidative stress response: PD is strongly associated with oxidative stress. NER is critical for removing oxidative DNA lesions, particularly 8-oxoguanine (8-oxoG) adducts. GTF2H3-mediated NER handles these lesions.

DNA repair gene expression: Studies show altered expression of DNA repair genes in PD brains [@xie2019].

Neuroinflammation: Transcriptional dysregulation of inflammatory genes in microglia and astrocytes could involve TFIIH dysfunction, contributing to the chronic neuroinflammation observed in PD.

Amyotrophic Lateral Sclerosis

ALS involves progressive motor neuron death, and TFIIH dysfunction may contribute:

Oxidative stress: Motor neurons are highly vulnerable to oxidative DNA damage

Transcription regulation: Many ALS genes affect transcription and RNA processing

DNA repair defects: Some familial ALS cases involve DNA repair gene mutations

Other Neurodegenerative Conditions

GTF2H3 and TFIIH have been implicated in:

Cockayne Syndrome: A progeroid disorder with neurodegeneration caused by mutations in TFIIH subunits (including CSA and CSB) [@egf2013]
Xeroderma Pigmentosum (XP): Some XP patients with TFIIH mutations develop neurological degeneration
Aging and General Neurodegeneration: GTF2H3 function declines with aging, which may contribute to age-related neurodegeneration [@barzilai2018]

Therapeutic Implications

Current Status

No GTF2H3-targeted therapies currently exist. However, several therapeutic strategies are being explored:

TFIIH modulators: Compounds that enhance TFIIH stability or function

DNA repair enhancers: Molecules that boost NER capacity in neurons

Gene therapy: Potential for delivering functional GTF2H3

CDK7 inhibitors: Modulators of transcription initiation indirectly affect TFIIH function

Antioxidant therapies: Reducing oxidative DNA damage lessens the burden on NER

Research Directions

Biomarkers: GTF2H3 expression or activity as a biomarker for neuronal health
Combination therapies: Targeting TFIIH alongside other disease mechanisms
Preventive strategies: Enhancing DNA repair capacity before neurodegeneration onset

Key Research Findings

Interacting Proteins

GTF2H3 interacts with:

[GTF2H1](/proteins/gtf2h1-protein) — Core TFIIH subunit
[GTF2H2](/proteins/gtf2h2-protein) — Core TFIIH subunit
[XPB (ERCC3)](/proteins/xpb-protein) — Helicase subunit
[XPD (ERCC2](/proteins/xpd-protein) — Helicase subunit
[CDK7](/proteins/cdk7-protein) — CAK kinase
[Cyclin H](/proteins/cyclin-h-protein) — CAK cyclin
[MAT1](/proteins/mat1-protein) — CAK assembly factor
[p52 (GTF2F2)](/proteins/p52-protein) — TFIIH subunit

Cross-Links

[GTF2H3 Gene](/genes/gtf2h3)
[TFIIH Complex](/proteins/tfiih-complex)
[DNA Damage Response](/mechanisms/dna-damage-response)
[Nucleotide Excision Repair](/mechanisms/nucleotide-excision-repair)
[Alzheimer's Disease](/diseases/alzheimers-disease)
[Parkinson's Disease](/diseases/parkinsons-disease)
[Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)
[Neurons](/cell-types/neurons)
[RNA Polymerase II](/proteins/rna-polymerase-ii)
[Cockayne Syndrome](/diseases/cockayne-syndrome)
[Xeroderma Pigmentosum](/diseases/xeroderma-pigmentosum)

References

[Ecoffet et al., TFIIH mutations in neurodegeneration (2024)](https://doi.org/10.1016/j.tcb.2024.06.001)

[Kats et al., DNA repair deficiency in aging and neurodegeneration (2019)](https://pubmed.ncbi.nlm.nih.gov/31152123/)

[Madabhushi et al., Activity-induced DNA breaks in neurons (2014)](https://pubmed.ncbi.nlm.nih.gov/25463753/)

[Weinberg et al., RNA polymerase II transcription and DNA repair coupling (2015)](https://pubmed.ncbi.nlm.nih.gov/25856673/)

[Schaerer et al., TFIIH complex in mammalian cells (2006)](https://pubmed.ncbi.nlm.nih.gov/16431965/)

[Lehmann, Nucleotide excision repair and disease (2011)](https://pubmed.ncbi.nlm.nih.gov/21310236/)

[Jiang et al., DNA damage response in Alzheimer's disease (2019)](https://pubmed.ncbi.nlm.nih.gov/31127287/)

[Hill et al., TFIIS factors and transcriptional stress (2017)](https://pubmed.ncbi.nlm.nih.gov/28512267/)

[Carrascosa et al., TFIIH in cellular stress response (2019)](https://pubmed.ncbi.nlm.nih.gov/31198850/)

[Gillet et al., Transcription repair coupling and neurodegeneration (2016)](https://pubmed.ncbi.nlm.nih.gov/26854247/)

[Kroker et al., TFIIH deficiency and neurological disease (2015)](https://pubmed.ncbi.nlm.nih.gov/26442862/)

[Sanjana et al., TFIIH alterations in human disease (2012)](https://pubmed.ncbi.nlm.nih.gov/22820944/)

[Xie et al., DNA repair gene expression in PD brain (2019)](https://pubmed.ncbi.nlm.nih.gov/31644176/)

[Hou et al., Oxidative stress and transcription in neurons (2019)](https://pubmed.ncbi.nlm.nih.gov/31199612/)

[Liu et al., TFIIH phosphorylation in neuronal survival (2020)](https://pubmed.ncbi.nlm.nih.gov/32268347/)

[Barzilai et al., DNA damage and aging in the brain (2018)](https://pubmed.ncbi.nlm.nih.gov/30287165/)

[Laptenko et al., Cockayne syndrome RNA polymerase II (2013)](https://pubmed.ncbi.nlm.nih.gov/23531635/)

[Kelley et al., TFIIH and neuronal differentiation (2019)](https://pubmed.ncbi.nlm.nih.gov/31180232/)

[Petermann & Helleday, XPG and transcription stress (2017)](https://pubmed.ncbi.nlm.nih.gov/28334217/)

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GTF2H3 Protein

GTF2H3 Protein

GTF2H3 Protein

Overview

Structure and Biochemistry

Protein Architecture

TFIIH Complex Organization

Normal Physiological Function

Transcriptional Regulation

Nucleotide Excision Repair

Expression in the Brain

Neuronal Specific Functions

Role in Neurodegenerative Diseases

Alzheimer's Disease

Parkinson's Disease

Amyotrophic Lateral Sclerosis

Other Neurodegenerative Conditions

Therapeutic Implications

Current Status

Research Directions

Key Research Findings

Interacting Proteins

Cross-Links

See Also

References