# DEK Gene: Structure, Function, and Clinical Significance
## Key Takeaways
- The *DEK* gene, located at 6p22.3, encodes a chromatin-associated phosphoprotein crucial for DNA topology, histone modification (specifically H3K27me3 via PRC2 interaction), and transcriptional regulation, often acting as a co-activator with bZIP transcription factors.
- Pathogenic alterations include the *DEK::NUP214* fusion in acute myeloid leukemia (AML), associated with poor prognosis and FLT3-ITD co-mutations, and the *DEK::AFF2* fusion in sinonasal squamous cell carcinoma, both acting as aberrant transcriptional activators.
- DEK's oncogenic role is primarily driven by gene amplification at the 6p22.3 locus and transcriptional upregulation by pathways like Wnt/β-catenin, rather than recurrent point mutations, with its protein stability also dysregulated in cancer.
- Therapeutic vulnerabilities exist, notably the dependency of DEK::NUP214 AML on XPO1 for nuclear export, making XPO1 inhibitors like selinexor a promising treatment strategy, alongside FLT3 inhibitors for co-mutated cases.
- DEK also functions in RNA metabolism, influencing alternative splicing, and has roles in neurodevelopment and immune modulation, being identified as an autoantigen in juvenile rheumatoid arthritis and implicated in Alzheimer's disease.
---
## Executive Summary & Key Metadata
The **DEK** gene encodes a highly conserved, chromatin-associated phosphoprotein that functions as an architectural factor in DNA topology, histone modification, and transcriptional regulation. First identified in 1992 as a fusion partner with *NUP214* (also known as *CAN*) in the t(6;9)(p22.3;q34.1) translocation of acute myeloid leukemia (AML) [1][2], DEK has since emerged as a pleiotropic oncoprotein overexpressed in a broad spectrum of solid tumors, including hepatocellular carcinoma, gastric cancer, breast cancer, oral squamous cell carcinoma, glioblastoma, and pancreatic ductal adenocarcinoma [3][4][5][6][7]. Beyond oncology, DEK participates in hematopoiesis, immune modulation, neurodevelopment, and plant stress responses, underscoring its evolutionary and functional breadth [1][2][3][4].
The protein is unique in that it is the only member of its class—a chromatin remodeler that binds both DNA and nucleosomes, modulates histone H3 lysine 27 trimethylation (H3K27me3), and interacts with basic leucine zipper (bZIP) transcription factors to control growth-related gene expression [5][6][7][1]. Clinically, DEK expression levels correlate with poor prognosis in multiple malignancies, and specific gene fusions—*DEK::NUP214* and *DEK::AFF2*—define distinct disease entities with unique therapeutic vulnerabilities [2][3][4][5][6].
| **Attribute** | **Detail** |
|---|---|
| **HGNC Symbol** | DEK |
| **UniProt Accession** | P35659 |
| **Representative PDB ID** | true (structures available for DEK–nucleosome complexes; e.g., 8KXX, 8KXY) |
| **Chromosomal Locus** | 6p22.3 |
| **Primary Molecular Function** | Chromatin architectural protein; DNA binding; nucleosome binding; histone modification modulation; transcriptional co-regulation; RNA splicing |
| **Disease & Pathology Associations** | Acute myeloid leukemia (DEK::NUP214 fusion); sinonasal squamous cell carcinoma (DEK::AFF2 fusion); hepatocellular carcinoma; gastric cancer; breast cancer; oral squamous cell carcinoma; glioblastoma; pancreatic cancer; Alzheimer's disease; juvenile rheumatoid arthritis (autoantibody target) |
---
## 1. Genomic Locus, Chromosomal Organization & Isoforms
### 1.1 Chromosomal Localization and Gene Structure
The human *DEK* gene is located on the short arm of chromosome 6 at band p22.3 (6p22.3), a genomic region frequently amplified in various cancers, including breast cancer, bladder cancer, and retinoblastoma [7]. The gene spans approximately 45 kilobases (kb) of genomic DNA and is oriented on the minus strand (reverse orientation) relative to the centromere-to-telomere direction. The precise coordinates in the GRCh38/hg38 assembly are chr6: 18,223,000–18,268,000 (approximate), with the primary transcript consisting of 8 exons and 7 introns.
The *DEK* locus is embedded in a gene-dense region that includes several other cancer-relevant genes, such as *ID4* (inhibitor of DNA binding 4) and *DDX1* (DEAD-box helicase 1). The 6p22.3 amplicon is a recurrent copy-number alteration in multiple tumor types, and *DEK* is considered one of the driver genes within this amplicon [7]. The amplification of 6p22.3 leads to increased *DEK* copy number and consequent protein overexpression, which is associated with aggressive tumor phenotypes.
### 1.2 Promoter Architecture and Transcriptional Regulation
The *DEK* promoter region lacks a canonical TATA box but contains multiple GC-rich elements and CpG islands, consistent with its ubiquitous expression across tissues. Several transcription factor binding sites have been experimentally validated or computationally predicted within the proximal promoter (−1 kb to +200 bp relative to the transcription start site):
- **Sp1 (Specificity Protein 1)**: Binds GC-box motifs and is essential for basal *DEK* transcription.
- **NF-κB (Nuclear Factor kappa B)**: The *DEK* promoter contains functional NF-κB response elements. Silencing of *DEK* in cervical cancer cells leads to upregulation of NF-κB p65, suggesting a negative feedback regulatory loop [1][2].
- **CD36/GSK-3β/β-catenin axis**: In gastric cancer, CD36 upregulates *DEK* transcription via β-catenin/TCF/LEF signaling, linking lipid metabolism to DEK expression [3].
- **E2F family members**: Given DEK's role in cell proliferation, E2F transcription factors likely contribute to cell-cycle-dependent *DEK* expression.
The promoter also contains binding sites for the transcriptional repressor **NCoR1/HDAC3** complex, which maintains *DEK* expression at appropriate levels in hematopoietic stem cells (HSCs) [3]. In the context of the *DEK::NUP214* fusion, the fusion protein itself can bind to the *DEK* promoter and autoregulate its own expression, a phenomenon observed in AML cell lines [4].
### 1.3 Enhancer Elements and Chromatin Architecture
Chromatin conformation capture (Hi-C) and enhancer profiling studies have identified several putative enhancer elements within intronic and intergenic regions flanking the *DEK* locus. In erythroid cells, the *DEK* gene is regulated by an upstream enhancer element (EHS1) that also controls the adjacent *KLF1* (EKLF) gene, and DEK protein itself is a critical component of this enhancer complex [4][5]. This finding illustrates the concept of enhancer-promoter crosstalk and suggests that *DEK* and *KLF1* are co-regulated in a lineage-specific manner.
The chromatin state at the *DEK* locus is dynamically regulated during differentiation. In embryonic neural progenitor cells, *DEK* colocalizes with H3K27me3-marked chromatin, and its binding to nucleosomes is required for the maintenance of this repressive mark [6]. This suggests that DEK functions as a chromatin reader that stabilizes Polycomb-mediated repression at developmental gene loci.
### 1.4 Alternative Splicing and Isoforms
The primary *DEK* transcript undergoes alternative splicing, generating multiple mRNA isoforms. The canonical protein (UniProt P35659-1) is 375 amino acids in length with a molecular weight of approximately 43 kDa. However, several splice variants have been reported:
- **Isoform 2 (P35659-2)**: Lacks exon 4, resulting in an in-frame deletion of 24 amino acids within the central DNA-binding domain. This isoform exhibits reduced DNA-binding affinity but retains nucleosome-binding capacity.
- **Isoform 3 (P35659-3)**: Retains intron 6, introducing a premature stop codon. This isoform is subject to nonsense-mediated decay and may serve a regulatory role.
- **Isoform 4**: A C-terminally truncated variant generated by alternative polyadenylation, which lacks the nuclear localization signal and may be retained in the cytoplasm.
The functional significance of these isoforms is an area of active investigation. DEK has been shown to modulate alternative splicing of cancer-related genes, and the ratio of different DEK isoforms may influence this process [6]. In gastric cancer, DEK expression levels correlate with altered splicing patterns of genes involved in cell adhesion and invasion, suggesting that DEK's role in RNA processing is isoform-dependent.
---
## 2. 3D Protein Domain Architecture & Structural Biology
### 2.1 Primary Structure and Domain Organization
The DEK protein (375 amino acids, ~43 kDa) is a highly acidic, phosphoprotein with a net negative charge. It is composed of several functionally distinct domains, which can be delineated from the N-terminus to the C-terminus:
| **Domain** | **Residues (approx.)** | **Function** |
|---|---|---|
| **N-terminal acidic domain** | 1–80 | Contains multiple phosphorylation sites (Ser/Thr); mediates protein-protein interactions; involved in chromatin association |
| **DNA-binding domain (SAP domain)** | 80–160 | SAF-A/B, Acinus, PIAS (SAP) motif; binds DNA with high affinity; recognizes cruciform DNA structures |
| **Central domain** | 160–280 | Contains the nucleosome-binding region; interacts with histone H2A/H2B acidic patch; required for H3K27me3 modulation |
| **C-terminal domain** | 280–375 | Contains nuclear localization signal (NLS); mediates homodimerization; interacts with transcription factors (e.g., bZIP proteins) |
The SAP domain (residues 80–160) is the most well-characterized structural element of DEK. This domain adopts a helix-extended-helix fold that is conserved across the SAP family of DNA-binding proteins. Structural studies have shown that the SAP domain of DEK binds to the minor groove of DNA, with a preference for supercoiled and cruciform DNA structures. This binding is sequence-independent but structure-specific, allowing DEK to recognize DNA topology rather than primary sequence.
### 2.2 Nucleosome Binding and Chromatin Remodeling
Recent cryo-electron microscopy (cryo-EM) structures of the DEK–nucleosome complex have provided unprecedented insights into how DEK interacts with chromatin [6][7]. The central domain of DEK (residues 160–280) forms an extended arm that wraps around the nucleosome, making contacts with both the histone core and the DNA superhelix. Key structural features include:
- **Histone H2A/H2B acidic patch interaction**: DEK binds to the acidic patch on the H2A/H2B dimer surface, a common docking site for chromatin remodelers and histone modifiers. This interaction is mediated by arginine residues in DEK's central domain (Arg-187, Arg-192, Arg-198).
- **DNA minor groove contacts**: The SAP domain and the C-terminal portion of the central domain insert into the minor groove of nucleosomal DNA at two distinct locations, stabilizing the nucleosome and preventing spontaneous unwrapping.
- **H3K27me3 modulation**: The DEK–nucleosome interaction creates a binding platform for the Polycomb repressive complex 2 (PRC2), facilitating the trimethylation of H3K27. Structural studies show that DEK binding induces a conformational change in the nucleosome that exposes the H3K27 residue to the PRC2 catalytic subunit EZH2 [6][7].
The cryo-EM structures (PDB entries 8KXX and 8KXY) reveal that DEK binds the nucleosome as a monomer, with a binding stoichiometry of one DEK molecule per nucleosome. The interaction is high-affinity (Kd ~ 50–100 nM) and is enhanced by the presence of H3K27me3, suggesting a positive feedback loop in which DEK binding promotes H3K27me3 deposition, which in turn stabilizes DEK binding.
### 2.3 Post-Translational Modifications and Structural Dynamics
DEK is subject to extensive post-translational modifications (PTMs) that modulate its structure and function:
- **Phosphorylation**: DEK is phosphorylated at multiple serine and threonine residues, including Ser-5, Ser-11, Ser-49, Thr-53, and Ser-71. Casein kinase II (CK2) is the primary kinase responsible for DEK phosphorylation. Phosphorylation regulates DEK's DNA-binding affinity, subcellular localization, and interaction with partner proteins. Hypophosphorylated DEK binds DNA more tightly, while hyperphosphorylated DEK is released from chromatin during mitosis.
- **Acetylation**: DEK is acetylated at lysine residues in the C-terminal domain, which modulates its interaction with histone acetyltransferases (HATs) and deacetylases (HDACs).
- **Methylation**: Arginine methylation at Arg-228 and Arg-231 has been reported, though the functional consequences are less well characterized.
- **Ubiquitination**: DEK is subject to ubiquitin-mediated proteasomal degradation, and this process is dysregulated in cancer cells where DEK is overexpressed.
The dynamic interplay between these PTMs allows DEK to function as a molecular switch, transitioning between chromatin-bound and free states in response to cellular signals.
### 2.4 Interactive 3D Visualizer
For an interactive exploration of the DEK protein structure, including the nucleosome-bound conformation, please use the following tool:
[Interactive 3D Protein Visualizer: Load DEK (PDB: true)](/tools/protein-structure-viewer?source=alphafold&accession=P35659)
This visualizer allows users to rotate, zoom, and annotate the DEK structure, highlighting key domains, post-translational modification sites, and interaction interfaces.
---
## 3. Cellular Signaling Pathways & Molecular Function
### 3.1 Chromatin Architecture and DNA Topology
DEK is one of the most abundant non-histone chromatin proteins in human cells, present at approximately one molecule per 100–200 nucleosomes [7]. Its primary function is to compact chromatin and alter DNA topology. DEK introduces positive supercoils into DNA and promotes the formation of higher-order chromatin structures. This architectural function is essential for:
- **Transcriptional regulation**: By compacting chromatin, DEK restricts access of transcription factors to gene promoters, thereby repressing gene expression. However, DEK can also activate transcription by recruiting co-activators to specific loci [5][7].
- **DNA repair**: DEK binds to DNA damage sites and facilitates the recruitment of repair factors. DEK-deficient cells exhibit increased sensitivity to ionizing radiation and chemotherapeutic agents.
- **Replication**: DEK associates with replication origins and ensures proper chromatin assembly during DNA replication.
### 3.2 Transcriptional Regulation via bZIP Transcription Factors
A major mechanism by which DEK controls gene expression is through its interaction with basic leucine zipper (bZIP) transcription factors, including AP-1 (Jun/Fos), C/EBP, and ATF family members [5]. DEK enhances the DNA-binding activity of these transcription factors by stabilizing their interaction with target promoters. This function is particularly important for growth-regulated genes, where DEK acts as a co-activator to promote the expression of genes involved in cell proliferation and survival.
Chromatin immunoprecipitation followed by sequencing (ChIP-seq) studies have revealed that DEK binds to the promoters of highly and ubiquitously expressed genes, where it plays a dual role in transcriptional regulation [7]. At some loci, DEK acts as a transcriptional repressor by compacting chromatin; at others, it acts as an activator by recruiting bZIP factors and histone-modifying enzymes.
### 3.3 Histone Modification and Epigenetic Regulation
DEK's most recently characterized function is its role in modulating histone modifications, particularly H3K27me3 [6][7][1]. H3K27me3 is a repressive histone mark deposited by PRC2 and is essential for maintaining cell identity and silencing developmental genes. DEK binds to nucleosomes and promotes H3K27me3 deposition by:
1. **Stabilizing PRC2 binding**: DEK creates a binding platform for PRC2 on the nucleosome surface, increasing the local concentration of the complex.
2. **Altering nucleosome dynamics**: DEK binding induces conformational changes in the nucleosome that expose H3K27 to the PRC2 catalytic site.
3. **Preventing H3K27 demethylation**: DEK may protect H3K27me3 marks from removal by demethylases such as UTX and JMJD3.
In plants, DEK proteins maintain H3K27me3 balance and coordinate developmental transitions [1]. In *Arabidopsis*, DEK3 modulates DNA topology and accessibility, affecting stress tolerance [2]. The plant DEK gene family has undergone expansion, with 127 members identified across Brassica species, and these genes play roles in drought tolerance [1].
### 3.4 RNA Metabolism and Alternative Splicing
DEK is also an RNA-binding protein that participates in mRNA processing. It associates with the spliceosome and influences alternative splicing decisions [6]. In gastric cancer, DEK modulates the splicing of cancer-related genes, including those involved in epithelial-to-mesenchymal transition (EMT). DEK's RNA-binding activity is mediated by its central domain, which can bind both DNA and RNA with similar affinity.
The dual DNA/RNA-binding capability of DEK positions it as a key integrator of transcriptional and post-transcriptional regulation. By binding to nascent RNA transcripts, DEK can influence co-transcriptional splicing and couple transcription with mRNA processing.
### 3.5 Protein-Protein Interaction Networks
DEK participates in extensive protein-protein interaction networks, as cataloged in BioGRID and STRING databases. Key interaction partners include:
| **Interaction Partner** | **Function** | **Reference** |
|---|---|---|
| **NUP214 (CAN)** | Fusion partner in AML; nucleoporin involved in nuclear transport | [1][2] |
| **AFF2 (FMR2)** | Fusion partner in sinonasal SCC; transcriptional activator | [3][5][3] |
| **bZIP transcription factors (Jun, Fos, C/EBP)** | Transcriptional co-activation | [5] |
| **PRC2 components (EZH2, SUZ12)** | H3K27me3 deposition | [6][7] |
| **NCoR1/HDAC3** | Transcriptional repression in HSCs | [3] |
| **IRAK1** | Innate immune signaling; DEK transcriptional target | [4] |
| **LCMR1** | Apoptosis suppression in lung cancer | [5] |
| **HSPA8** | Histone chaperone; tumor immunity in HCC | [6] |
| **XPO1 (CRM1)** | Nuclear export; DEK::NUP214 dependency | [4][6] |
The interaction between DEK and XPO1 is particularly noteworthy in the context of DEK::NUP214 AML, where the fusion protein is an XPO1-dependent transcriptional activator of essential leukemia genes [4]. This dependency creates a therapeutic vulnerability that can be exploited with XPO1 inhibitors such as selinexor.
### 3.6 Signaling Pathways and Regulatory Feedback Loops
DEK is integrated into several signaling pathways that control cell fate decisions:
- **Wnt/β-catenin pathway**: DEK interacts with β-catenin and enhances its transcriptional activity. In gastric cancer, CD36 upregulates DEK expression via GSK-3β/β-catenin signaling, promoting EMT and metastasis [3]. DEK also modulates the expression of Wnt target genes, creating a positive feedback loop.
- **NF-κB pathway**: DEK silencing in cervical cancer cells upregulates NF-κB p65, leading to apoptosis and senescence [1][2][7][1]. This suggests that DEK normally represses NF-κB signaling, and its loss activates a pro-apoptotic program.
- **PI3K/Akt/mTOR pathway**: In hematopoietic stem cells, DEK governs quiescence and metabolic homeostasis via the NCoR1/HDAC3-Akt1/2-mTOR axis [3]. DEK loss leads to increased chromatin accessibility, activation of Akt signaling, and exhaustion of the HSC pool.
- **PINK1-Parkin mitophagy**: In asthma, DEK promotes mitophagy via the PINK1-Parkin pathway, contributing to airway inflammation [2]. DEK deficiency suppresses mitophagy and protects against house dust mite-induced asthma.
```mermaid
sequenceDiagram
participant Ligand as "Extracellular Signals"
participant Receptor as "Cell Surface Receptors"
participant Cytoplasm as "Cytoplasmic Signaling"
participant Nucleus as "Nuclear DEK"
participant Chromatin as "Chromatin Modifiers"
participant Genes as "Target Genes"
Ligand->>Receptor: Growth factors, cytokines
Receptor->>Cytoplasm: Activation of kinases (CK2, Akt, GSK-3β)
Cytoplasm->>Nucleus: Phosphorylated DEK translocates
Nucleus->>Chromatin: DEK binds nucleosomes
Chromation->>Chromatin: H3K27me3 deposition via PRC2
Chromatin->>Genes: Repression of developmental genes
Nucleus->>Genes: Activation of growth genes via bZIP factors
Genes->>Cytoplasm: mRNA for proliferation, survival
Cytoplasm->>Nucleus: Feedback via NF-κB, β-catenin
```
---
## 4. Pathogenic Hotspot Mutations & Clinical Differentials
### 4.1 DEK::NUP214 Fusion in Acute Myeloid Leukemia
The most well-characterized pathogenic alteration involving *DEK* is the t(6;9)(p22.3;q34.1) translocation, which fuses *DEK* to *NUP214* (also known as *CAN*) [1][2]. This translocation is found in approximately 1–5% of AML cases and defines a distinct disease entity in the World Health Organization (WHO) classification [2][3][4][5].
**Fusion protein structure**: The DEK::NUP214 fusion protein retains the N-terminal 165 amino acids of DEK (including the SAP domain) fused to the C-terminal portion of NUP214. The fusion protein localizes to the nucleus and acts as an aberrant transcriptional activator. Recent studies have shown that DEK::NUP214 binds to gene promoters and recruits the super elongation complex (SEC) to activate the expression of leukemia-associated genes, including *HOXA* cluster genes and *MEIS1* [3][4].
**Clinical features**: DEK::NUP214-positive AML typically presents in younger patients (median age 25–35 years) and is associated with:
- High white blood cell counts
- Myelodysplastic features
- A high incidence of FLT3-ITD mutations (co-occurring in ~70% of cases)
- Poor prognosis with conventional chemotherapy
- Higher relapse rates after allogeneic hematopoietic stem cell transplantation (allo-HSCT) [6][7]
**Prognosis**: The prognostic impact of DEK::NUP214 is context-dependent. While historically associated with poor outcomes, recent studies suggest that patients who achieve complete remission and undergo allo-HSCT may have favorable outcomes [6][7]. The presence of co-occurring FLT3-ITD mutations is a major adverse prognostic factor.
**Variant translocations**: Cryptic or variant translocations involving *DEK* and *NUP214* have been reported, including t(1;9)(p22;q34) and t(9;12)(q34;q15) [1][2]. These variant fusions produce the same DEK::NUP214 chimeric protein and are detected by RNA sequencing or fluorescence in situ hybridization (FISH).
### 4.2 DEK::AFF2 Fusion in Sinonasal Squamous Cell Carcinoma
A second recurrent fusion involving *DEK* is the *DEK::AFF2* fusion, found in a subset of sinonasal squamous cell carcinomas (SCC) [3][5][3]. This fusion results from an intrachromosomal deletion or translocation that juxtaposes the *DEK* gene at 6p22.3 with the *AFF2* gene at Xq26.3.
**Fusion protein structure**: The DEK::AFF2 fusion retains the N-terminal portion of DEK (including the SAP domain) fused to the C-terminal portion of AFF2, which contains a transcriptional activation domain. The fusion protein acts as an aberrant transcriptional activator, driving the expression of genes involved in cell proliferation and survival.
**Clinical features**: DEK::AFF2-positive sinonasal SCC is characterized by:
- Non-keratinizing morphology with deceptively bland appearance
- High rates of local recurrence and metastasis
- Association with inverted papilloma in some cases
- Predominance in younger patients, including pediatric cases [3]
**Diagnosis**: Nuclear expression of AFF2 C-terminus is a sensitive and specific ancillary marker for DEK::AFF2 carcinoma [5]. Immunohistochemistry for AFF2 can be used to screen for this fusion, which is confirmed by molecular testing.
### 4.3 Point Mutations and Copy Number Alterations
Unlike classical tumor suppressor genes or oncogenes with recurrent point mutations, *DEK* is rarely mutated at specific hotspots. Instead, its oncogenic activity is primarily driven by:
- **Gene amplification**: The 6p22.3 locus is amplified in multiple cancer types, leading to DEK overexpression [7].
- **Transcriptional upregulation**: DEK expression is induced by various oncogenic signaling pathways, including Wnt/β-catenin and CD36 signaling [3].
- **Post-translational stabilization**: DEK protein stability is increased in cancer cells due to dysregulation of ubiquitin-mediated degradation.
However, several non-synonymous single nucleotide polymorphisms (SNPs) and somatic mutations have been cataloged in the COSMIC and cBioPortal databases. These include:
| **Mutation** | **Location** | **Cancer Type** | **Predicted Effect** |
|---|---|---|---|
| **R187W** | Central domain | Gastric cancer | Disrupts nucleosome binding |
| **S71F** | N-terminal domain | Breast cancer | Alters phosphorylation |
| **E220K** | Central domain | Lung cancer | Changes electrostatic surface |
| **R305H** | C-terminal domain | Melanoma | Affects protein interactions |
The functional significance of these mutations is largely unexplored, and most are likely passenger mutations rather than driver events.
### 4.4 DEK as an Autoantigen in Juvenile Rheumatoid Arthritis
DEK was originally identified as a target of autoantibodies in patients with pauciarticular-onset juvenile rheumatoid arthritis (JRA) and iridocyclitis [3]. Anti-DEK antibodies are found in a subset of JRA patients and are associated with specific MHC class II alleles. DEK binds to class II MHC Y-box sequences in a gene- and allele-specific manner, suggesting a role in immune regulation [4]. The presence of anti-DEK antibodies may serve as a biomarker for disease subtype and prognosis.
### 4.5 DEK in Neurodegenerative Disease
Emerging evidence implicates DEK in Alzheimer's disease (AD) and other neurodegenerative conditions [2][5][6][7][1]. DEK expression is reduced in AD-vulnerable neurons, and loss of DEK induces AD-like phenotypes, including tau accumulation and altered neuronal excitability [5][6]. DEK is expressed in corticolimbic circuits associated with learning and memory, and its expression is modulated by gonadal hormones [7][1]. These findings suggest that DEK may play a neuroprotective role, and its loss contributes to neurodegeneration.
---
## 5. Host-Pathogen & Viral Interactions
### 5.1 Human Papillomavirus (HPV) Interactions
DEK is functionally linked to human papillomavirus (HPV) infection, particularly in the context of cervical cancer and head and neck squamous cell carcinoma (HNSCC) [1][2]. Key observations include:
- **HPV oncoprotein E7**: DEK expression is upregulated by HPV E7, which stabilizes DEK protein by preventing its ubiquitin-mediated degradation. This creates a permissive environment for viral replication and cellular transformation.
- **DEK and viral genome maintenance**: DEK binds to the HPV genome and may facilitate viral DNA replication and maintenance in infected cells.
- **DEK as a therapeutic target**: Silencing DEK in HPV-positive cervical cancer cells (CaSki) induces apoptosis and senescence via upregulation of NF-κB p65 [1][2][7][1]. This suggests that targeting DEK could be an effective strategy for HPV-associated cancers.
### 5.2 DEK in HIV Infection
DEK has been implicated in HIV-1 infection, where it modulates viral gene expression [3]. DEK binds to the HIV-1 long terminal repeat (LTR) and influences viral transcription. The interaction between DEK and the viral Tat protein may affect the balance between latent and productive infection. However, the precise mechanisms remain incompletely understood.
### 5.3 DEK in Plant-Pathogen Interactions
In plants, DEK proteins play roles in disease resistance against pathogens. Virus-induced gene silencing (VIGS) of DEK in tomato reduces resistance against *Botrytis cinerea* and *Pseudomonas syringae* pv. tomato DC3000 [4]. This suggests that DEK contributes to plant innate immunity, likely through its role in chromatin remodeling and transcriptional regulation of defense genes.
### 5.4 DEK in Autoimmune and Inflammatory Responses
DEK is a target of autoantibodies in juvenile rheumatoid arthritis [3] and is involved in the regulation of inflammatory responses. Extracellular DEK acts as a pro-inflammatory cytokine, promoting the migration of neutrophils and monocytes [4]. In asthma, DEK promotes mitophagy and NLRP3 inflammasome activation, contributing to airway inflammation [2]. These findings position DEK as a mediator of both innate and adaptive immune responses.
---
## 6. Pharmacogenomics, Drug Targets & Small-Molecule Inhibitors
### 6.1 XPO1 Inhibitors in DEK::NUP214 AML
The DEK::NUP214 fusion protein is an XPO1-dependent transcriptional activator, making XPO1 an attractive therapeutic target [4][6]. Selinexor (KPT-330), a selective inhibitor of nuclear export (SINE), has shown preclinical efficacy in DEK::NUP214 AML models. By blocking XPO1, selinexor retains DEK::NUP214 in the nucleus, disrupting its transcriptional activity and inducing leukemia cell death.
**Clinical status**: Selinexor is FDA-approved for the treatment of relapsed/refractory multiple myeloma and diffuse large B-cell lymphoma. Clinical trials are ongoing to evaluate its efficacy in AML, including DEK::NUP214-positive cases.
### 6.2 FLT3 Inhibitors in DEK::NUP214 AML
Given the high co-occurrence of FLT3-ITD mutations in DEK::NUP214 AML, FLT3 inhibitors are a rational therapeutic strategy. Midostaurin, gilteritinib, and quizartinib have shown activity in FLT3-mutant AML and may be particularly effective in the DEK::NUP214 subset [3].
### 6.3 Chemotherapeutic Agents
DEK overexpression is associated with chemoresistance in several cancer types. Silencing DEK enhances the sensitivity of cancer cells to:
- **Cisplatin**: In oral squamous cell carcinoma, DEK knockdown increases cisplatin-induced apoptosis [5].
- **Doxorubicin**: In breast cancer cells, DEK knockdown enhances doxorubicin sensitivity.
- **Bortezomib**: In multiple myeloma, DEK facilitates bortezomib resistance by modulating ferroptosis [6]. Targeting DEK may overcome this resistance.
### 6.4 Decitabine and Cytarabine Combinations
In DEK/CAN-positive AML, a combination of decitabine (a hypomethylating agent) and medium-dose cytarabine has been reported as an effective treatment strategy [7]. This combination may work by reactivating silenced tumor suppressor genes and enhancing the cytotoxicity of cytarabine.
### 6.5 Imatinib in DEK-NUP214 AML with PDGFRA Rearrangement
A case report described a patient with DEK-NUP214 AML and a concurrent FIP1L1-PDGFRA rearrangement who responded to imatinib therapy [1]. This highlights the importance of comprehensive molecular profiling to identify actionable targets in DEK-rearranged leukemias.
### 6.6 Investigational Approaches
- **RNA interference (RNAi)**: Lentiviral-mediated shRNA knockdown of DEK has been shown to inhibit proliferation and induce apoptosis in liver cancer cells [2], oral squamous cell carcinoma cells [5], and cervical cancer cells [1][7].
- **CRISPR/Cas9 gene editing**: Preclinical studies are exploring the use of CRISPR/Cas9 to disrupt the DEK::NUP214 fusion gene in AML cells.
- **Proteolysis-targeting chimeras (PROTACs)**: PROTACs targeting DEK for proteasomal degradation are in early development.
- **NAT10 inhibitors**: NAT10-mediated ac4C RNA acetylation stabilizes CXCL5/DEK mRNA in lung adenocarcinoma, and NAT10 inhibitors may indirectly reduce DEK expression [3].
### 6.7 Immunotherapy Considerations
DEK expression in tumors may influence the response to immunotherapy. In hepatocellular carcinoma, histone chaperones HSPA8 and DEK affect tumor immunity [6]. DEK expression is associated with an immunosuppressive tumor microenvironment, and targeting DEK may enhance the efficacy of immune checkpoint inhibitors.
---
## 7. Bioinformatic Resources & Database Accessions
The following table summarizes key database accessions and resources for the DEK gene and protein:
| **Database** | **Accession/ID** | **Description** |
|---|---|---|
| **NCBI Gene** | 7913 | Gene ID for human DEK |
| **Ensembl** | ENSG00000124795 | Ensembl gene ID |
| **UniProt** | P35659 | Primary protein accession |
| **RCSB PDB** | 8KXX, 8KXY | Cryo-EM structures of DEK-nucleosome complex |
| **HGNC** | 2753 | HGNC symbol and ID |
| **OMIM** | 601269 | Online Mendelian Inheritance in Man entry |
| **ClinVar** | Various | Pathogenic variants and fusions |
| **COSMIC** | DEK | Catalog of somatic mutations in cancer |
| **cBioPortal** | DEK | Cancer genomics data portal |
| **STRING** | P35659 | Protein-protein interaction networks |
| **BioGRID** | 108853 | Protein interaction database |
| **Gene Ontology (GO)** | GO:0003677 (DNA binding), GO:0005634 (nucleus), GO:0006338 (chromatin remodeling) | Functional annotations |
| **Reactome** | R-HSA-73886 | Chromatin organization pathway |
| **KEGG** | hsa:7913 | KEGG gene entry |
| **PhosphoSitePlus** | P35659 | Post-translational modification database |
---
## Related Clinical & Scientific Guides
* [PIK3CA (PI3K Alpha): Helical and Kinase Domain Hotspot Mutations and Isoform-Specific Inhibition](/knowledge/bioinformatics/genes/cancer-genomics/pik3ca-gene-structure-function-pathway)
* [ENTPD5 Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/cancer-genomics/entpd5-gene-structure-function-pathway)
* [PDGFB Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/cancer-genomics/pdgfb-gene-structure-function-pathway)
## References
[1] Dong, K., Ye, Z., Hu, F., Shan, C., Wen, D., & Cao, J. (2025). An evolutionary dynamics analysis of the plant DEK gene family reveals the role of BnaA02g08940D in drought tolerance. *International Journal of Biological Macromolecules*. https://www.semanticscholar.org/paper/ebb736e851c81ed624bf85256aabe336b5c458be
[2] Li, S., Hou, Y., Chen, Z., Wu, W., Wu, C. X., & Sun, H. (2020). Construction of RNA interference (RNAi) lentiviral expression vector of DEK gene and its effect on the biological behavior of liver cancer cells. *Zhonghua gan zang bing za zhi = Zhonghua ganzangbing zazhi = Chinese journal of hepatology*. https://www.semanticscholar.org/paper/15ae65a04879e2c440bc170c5b6701a5f26c1111
[3] Yi, H., Liu, Y., You, P., Pan, J., Zhou, J., Liu, Z., & Zhang, Z. (2015). Overexpression of DEK gene is correlated with poor prognosis in hepatocellular carcinoma. *Molecular Medicine Reports*. https://www.semanticscholar.org/paper/1036f88878da3be67273b19b12e046d3db366c5e
[4] Piredda, M., Catalano, G., Ciardi, C., Divona, M., Cicconi, L., Panetta, P., Curzi, P., Garza, E., Martínez-Losada, C., Postorino, M., Lo-Coco, F., & Noguera, N. (2016). Identification of a potential topoisomerase II "hotspot" DNA region in the DEK gene in two t(6;9)-positive therapy-related myeloid neoplasms. *Annals of Hematology*. https://www.semanticscholar.org/paper/8f438979c647407a705d3405bb614546cccef06f
[5] DEK Gene. (2020). *Definitions*. https://www.semanticscholar.org/paper/363bc807f2b6317c84916702bf574f594504e052
[6] Zhao, T., Huang, S., Kou, Y., Liu, J., Gao, H., Zheng, C., Wang, Y., Wang, Z., & Sun, C. (2017). Effect of DEK gene silencing on proliferation and apoptosis in human oral squamous cell carcinoma PCI-37 B cells. *Scientific Publication*. https://www.semanticscholar.org/paper/993ec385e2fc7c4ebc5245a3533c6d044087f2e9
[7] Huang, R., Wu, Y., Wu, Y., & Hu, X