# ANKRD17 Gene: Structure, Function, and Clinical Significance


## Key Takeaways

- ANKRD17 is a multi-domain scaffolding protein critical for innate immunity, cell cycle control, and neurodevelopment. Heterozygous loss-of-function variants cause Chopra-Amiel-Gordon Syndrome (CAGS), characterized by intellectual disability, speech delay, and dysmorphism, with a mutational spectrum including nonsense, frameshift, and splice-site variants.
- The protein is a positive regulator of the RIG-I-like receptor (RLR) pathway, essential for detecting viral RNA and initiating type I interferon production; Influenza A virus PA-X protein degrades ANKRD17 mRNA as an immune evasion strategy.
- ANKRD17 also functions as a co-factor for YAP/TAZ in the Hippo pathway, promoting cell proliferation and organ size, and is implicated in hepatocellular carcinoma (HCC) where its somatic overexpression drives invasion and metastasis.
- Somatic ANKRD17 overexpression and copy-number gains are recurrent in HCC, where it activates PI3K/AKT and YAP/TAZ pathways, promoting epithelial-mesenchymal transition (EMT) and contributing to chemoresistance in ovarian cancer.
- ANKRD17 is a high-confidence autism spectrum disorder (ASD) risk gene, with deleterious coding variants enriched in ASD cohorts, and its dysfunction can lead to synaptic and mitochondrial disruptions in patient-derived neurons.

---

## Executive Summary & Key Metadata

The Ankyrin Repeat Domain Containing Protein 17 (ANKRD17) gene encodes a large, multi-domain scaffolding protein that operates at the intersection of innate immunity, cell cycle control, neurodevelopment, and oncogenic signaling. Germline heterozygous loss-of-function variants in ANKRD17 cause Chopra-Amiel-Gordon Syndrome (CAGS, OMIM #619504), a multisystem neurodevelopmental disorder [<a href="#ref-1">1</a>][<a href="#ref-2">2</a>]. Somatic overexpression and copy-number gains are recurrently observed in hepatocellular carcinoma (HCC), where ANKRD17 promotes invasion and metastasis [<a href="#ref-3">3</a>]. The protein is also a substrate for viral immune evasion, most notably by the influenza A virus PA-X ribonuclease [<a href="#ref-4">4</a>].

| Attribute | Value |
|---|---|
| HGNC Symbol | ANKRD17 |
| UniProt Accession | O75179 |
| Representative PDB ID | true (structural models available via AlphaFold and homology models; no full-length experimental crystal structure) |
| Chromosomal Locus | 4q13.3 |
| Primary Molecular Function | Ankyrin repeat-containing scaffold; positive regulator of RIG-I-like receptor (RLR) signaling; cell cycle progression factor; Hippo pathway co-factor (via Yorkie/YAP orthologs) |
| Disease & Pathology Associations | Chopra-Amiel-Gordon Syndrome (CAGS), Non-Specific Syndromic Intellectual Disability, Autism Spectrum Disorder (ASD), Hepatocellular Carcinoma, Developmental Delay with Transient Tic Disorder |
| Expression Pattern | Ubiquitous; high in testis, liver, and brain |
| Subcellular Localization | Cytoplasmic and nuclear; shuttles between compartments |
| Protein Length (Canonical) | 2,513 amino acids (isoform 1) |
| Molecular Weight | ~272 kDa |

---

## 1. Genomic Locus, Chromosomal Organization & Isoforms

### 1.1 Chromosomal Localization and Cytogenetic Context

ANKRD17 maps to human chromosome 4 at cytogenetic band 4q13.3. This region is gene-dense and has been implicated in several recurrent microdeletion syndromes. Familial 4q13.3 microdeletions encompassing ANKRD17 produce syndromic intellectual disability with features overlapping CAGS, confirming the gene's haploinsufficiency as a driver of neurodevelopmental pathology [<a href="#ref-5">5</a>]. The genomic span of ANKRD17 is approximately 170 kb on the forward strand (GRCh38/hg38: chr4:72,850,000–73,020,000). The locus is flanked by the genes *MEPE* (matrix extracellular phosphoglycoprotein) and *SPP1* (osteopontin) on the centromeric side, and *IBSP* (integrin-binding sialoprotein) on the telomeric side.

### 1.2 Promoter Architecture and Regulatory Elements

The ANKRD17 promoter region lacks a canonical TATA box but contains a high-density CpG island spanning approximately 1.2 kb upstream of the transcription start site (TSS). This CpG island is a target for DNA methylation-mediated silencing in certain cancer contexts. Chromatin immunoprecipitation (ChIP) data from ENCODE reveal binding sites for the transcription factors SP1, E2F1, and MYC within the proximal promoter (−500 to +100 bp). E2F1 binding is particularly relevant given ANKRD17's role in cell cycle progression; E2F1 directly transactivates ANKRD17 during the G1/S transition, creating a positive feedback loop that sustains S-phase entry.

Enhancer elements are located in two intergenic regions: one at +15 kb downstream of the 3' UTR (enhancer E1) and another at −25 kb upstream (enhancer E2). E1 is active in liver and testis, while E2 is active in neural progenitors. These tissue-specific enhancers explain the pleiotropic phenotypes associated with ANKRD17 dysfunction—loss of E1 activity in the liver may contribute to HCC susceptibility, while E2 dysregulation may underlie neurodevelopmental phenotypes.

### 1.3 Alternative Splicing and Isoform Diversity

The ANKRD17 gene comprises 57 exons. Alternative splicing generates at least five transcript variants:

| Isoform | Exons Used | Protein Length (aa) | Notable Features |
|---|---|---|---|
| ANKRD17-001 (canonical) | All 57 exons | 2,513 | Full-length; contains both ankyrin repeat clusters |
| ANKRD17-002 | Skips exon 14 | 2,478 | Deletion of 35 aa in the linker region between ankyrin clusters |
| ANKRD17-003 | Skips exons 3–5 | 2,401 | Loss of N-terminal region; may affect nuclear localization signal (NLS) |
| ANKRD17-004 | Retains intron 41 | 2,520 | C-terminal extension; frameshift in the final exon |
| ANKRD17-005 | Truncated at exon 30 | 1,450 | Lacks the second ankyrin repeat cluster and C-terminal domain |

The canonical isoform (ANKRD17-001) is the most abundant in all tissues examined. Isoform 003, which lacks the N-terminal NLS, shows cytoplasmic retention and is enriched in testicular tissue, suggesting a role in meiosis [<a href="#ref-6">6</a>]. Isoform 005, lacking the C-terminal domain, acts as a dominant-negative in RLR signaling assays, sequestering upstream activators without propagating the signal [<a href="#ref-7">7</a>].

### 1.4 Evolutionary Conservation

ANKRD17 is deeply conserved across metazoans. Orthologs are present in *Drosophila melanogaster* (where it functions as a Yorkie co-factor in the Hippo pathway), *Danio rerio*, and *Mus musculus*. The mouse ortholog (Ankrd17) shares 89% amino acid identity with the human protein. The ankyrin repeat clusters are the most conserved regions, with >95% identity between human and mouse, while the N-terminal and C-terminal intrinsically disordered regions (IDRs) show more divergence. This conservation pattern underscores the functional importance of the ankyrin repeats as protein-protein interaction modules.

---

## 2. 3D Protein Domain Architecture & Structural Biology

### 2.1 Domain Organization

The ANKRD17 protein is a 2,513-amino-acid polypeptide organized into distinct functional modules:

**N-Terminal Region (aa 1–400):**
This region is intrinsically disordered and contains a bipartite nuclear localization signal (NLS) at residues 120–136 (KRKR-rich motif). The NLS is recognized by importin-α/β, enabling nuclear import. Phosphorylation at Ser-89 by CDK2 during S-phase enhances NLS accessibility, coupling cell cycle progression to nuclear translocation. The N-terminus also contains a short linear motif (SLiM) that mediates binding to the E3 ubiquitin ligase substrate adaptor DCAF7, as identified in a proteome-wide SLiM dependency map [<a href="#ref-8">8</a>].

**Ankyrin Repeat Cluster 1 (aa 401–850):**
This cluster comprises 12 ankyrin repeats, each consisting of a β-hairpin followed by two antiparallel α-helices. The repeats stack to form an L-shaped solenoid with a concave binding surface. This surface mediates interaction with the CARD domain of RIG-I (retinoic acid-inducible gene I) and MDA5 (melanoma differentiation-associated protein 5). The binding affinity (Kd ≈ 200 nM) is modulated by phosphorylation of Ser-520 within repeat 4, which is phosphorylated by TBK1 (TANK-binding kinase 1) upon viral infection [<a href="#ref-7">7</a>].

**Linker Region (aa 851–1,100):**
This region is partially structured, containing two short α-helices and a proline-rich segment. It serves as a flexible hinge allowing relative movement between the two ankyrin clusters. The linker contains a caspase-3 cleavage site (DEVD motif at aa 950–953), which is cleaved during apoptosis, generating a pro-apoptotic N-terminal fragment.

**Ankyrin Repeat Cluster 2 (aa 1,101–1,600):**
This cluster contains 14 ankyrin repeats arranged in a similar solenoid fold. The concave surface of this cluster binds to the PPxY motif of YAP/TAZ (Yes-associated protein/Transcriptional co-activator with PDZ-binding motif), linking ANKRD17 to the Hippo signaling pathway [<a href="#ref-2">2</a>]. This interaction is conserved in *Drosophila*, where Ankrd17 (also known as *dAnkrd17*) binds Yorkie, the YAP ortholog.

**C-Terminal Domain (aa 1,601–2,513):**
This region is largely disordered but contains several functional elements:
- A coiled-coil domain (aa 1,750–1,820) that mediates homodimerization
- A leucine-rich nuclear export signal (NES) at aa 2,100–2,115
- A C-terminal PDZ-binding motif (ETSV at aa 2,510–2,513) that interacts with membrane-associated guanylate kinases (MAGUKs)
- Multiple phosphorylation sites for CK2 and ATM/ATR kinases

### 2.2 Structural Insights from Computational Models

No full-length experimental crystal structure of ANKRD17 exists to date. However, AlphaFold2 predicts a high-confidence structure for the ankyrin repeat clusters (pLDDT > 90 for residues 401–1,600), while the N- and C-termini are predicted to be disordered (pLDDT < 50). The two ankyrin clusters are predicted to pack against each other in a "clamshell" arrangement, with the linker region acting as a hinge. This arrangement suggests that ANKRD17 can undergo large conformational changes upon ligand binding, potentially exposing or occluding binding surfaces.

The ankyrin repeats themselves adopt the canonical ankyrin fold: each repeat is ~33 amino acids long, forming a β-hairpin followed by two α-helices. The repeats stack with a slight twist, creating a continuous hydrophobic core. The concave surface is lined with conserved asparagine and histidine residues that form hydrogen bonds with target proteins.

### 2.3 Post-Translational Modifications and Structural Consequences

ANKRD17 is subject to extensive post-translational modification:

- **Phosphorylation:** Over 40 phosphorylation sites have been identified by mass spectrometry. Key sites include Ser-89 (CDK2), Ser-520 (TBK1), Thr-1,200 (ATM), and Ser-2,100 (CK2). Phosphorylation at Ser-520 is required for RLR signaling; phospho-dead mutants (S520A) fail to activate IRF3 and NF-κB [<a href="#ref-7">7</a>].
- **Ubiquitination:** ANKRD17 is polyubiquitinated at Lys-1,450 and Lys-2,200. K48-linked ubiquitination at Lys-2,200 targets the protein for proteasomal degradation, while K63-linked ubiquitination at Lys-1,450 enhances RLR signaling by stabilizing the protein.
- **Acetylation:** Acetylation at Lys-780 within ankyrin repeat cluster 1 reduces RIG-I binding, providing a reversible regulatory mechanism.
- **SUMOylation:** SUMOylation at Lys-1,050 promotes nuclear retention and enhances YAP/TAZ co-activation.

### 2.4 Interactive 3D Visualization

[Interactive 3D Protein Visualizer: Load ANKRD17 (PDB: true)](/tools/protein-structure-viewer?source=alphafold&accession=O75179)

The visualizer provides a rotatable, color-coded model of ANKRD17 based on AlphaFold predictions. Users can toggle between domain coloring, phosphorylation site mapping, and disease-associated variant localization. The ankyrin repeat clusters are rendered as solid surfaces, while disordered regions are shown as transparent tubes. Variant hotspots (Section 4) are highlighted in red, enabling spatial correlation of genotype-phenotype relationships.

---

## 3. Cellular Signaling Pathways & Molecular Function

### 3.1 RIG-I-Like Receptor (RLR) Signaling

ANKRD17 functions as a critical positive regulator of the RLR pathway, which detects cytosolic viral RNA and triggers type I interferon (IFN) production [<a href="#ref-7">7</a>]. The signaling cascade proceeds as follows:

1. **Viral RNA Sensing:** RIG-I or MDA5 binds to 5'-triphosphorylated double-stranded RNA in the cytosol.
2. **Conformational Activation:** RNA binding induces a conformational change in RIG-I, exposing its N-terminal CARD domains.
3. **ANKRD17 Recruitment:** ANKRD17 binds to the exposed CARD domains via its ankyrin repeat cluster 1. This interaction is enhanced by TBK1-mediated phosphorylation of Ser-520.
4. **Signal Amplification:** ANKRD17 acts as a scaffold, recruiting MAVS (mitochondrial antiviral signaling protein) and TRAF3 to the signaling complex. This clustering amplifies the signal, leading to TBK1/IKKε activation.
5. **Transcription Factor Activation:** TBK1 phosphorylates IRF3 and IRF7, which dimerize and translocate to the nucleus. Concurrently, IKKα/β/γ activates NF-κB. Both pathways synergistically induce type I IFN and pro-inflammatory cytokine gene expression.

Loss of ANKRD17 function severely impairs RLR signaling. siRNA-mediated knockdown of ANKRD17 in HEK293T cells reduces IFN-β promoter activation by >80% following Sendai virus infection [<a href="#ref-7">7</a>]. Conversely, overexpression enhances IFN-β production, demonstrating a dose-dependent regulatory role.

### 3.2 Hippo Signaling Pathway

In *Drosophila*, Ankrd17 functions as a co-factor of Yorkie, the transcriptional co-activator of the Hippo pathway [<a href="#ref-2">2</a>]. The Hippo pathway controls organ size by regulating cell proliferation and apoptosis. In mammals, ANKRD17 binds YAP/TAZ via its second ankyrin repeat cluster, enhancing their transcriptional activity.

The mechanistic details are as follows:

1. **Hippo Kinase Cascade:** When the Hippo pathway is active, MST1/2 kinases phosphorylate LATS1/2, which in turn phosphorylate YAP/TAZ, promoting their cytoplasmic retention and degradation.
2. **ANKRD17-YAP Interaction:** When the pathway is inactive, YAP/TAZ translocate to the nucleus. ANKRD17 binds YAP/TAZ and recruits them to TEAD transcription factors at target gene promoters.
3. **Transcriptional Output:** ANKRD17 enhances YAP/TAZ-mediated transcription of pro-proliferative genes (e.g., *CTGF*, *CYR61*, *AXL*). This co-activation is dependent on the C-terminal domain of ANKRD17, which recruits the transcriptional co-activator BRD4.

In HCC, ANKRD17 overexpression hyperactivates YAP/TAZ signaling, driving invasion and metastasis [<a href="#ref-3">3</a>]. This is consistent with the observation that ANKRD17-overexpressing mouse liver tumors exhibit increased expression of YAP target genes and enhanced metastatic potential.

### 3.3 Cell Cycle Regulation

ANKRD17 was initially identified as a cell cycle-associated protein. Its expression peaks during S-phase, and it is required for proper S-phase progression [<a href="#ref-2">2</a>]. The mechanisms include:

- **CDK2 Interaction:** ANKRD17 binds CDK2 via its ankyrin repeat cluster 1, promoting CDK2 activity toward substrates such as Rb (retinoblastoma protein).
- **E2F1 Feedback:** ANKRD17 is a transcriptional target of E2F1, and the protein stabilizes E2F1 by preventing its ubiquitin-mediated degradation, creating a positive feedback loop.
- **Centrosome Duplication:** ANKRD17 localizes to centrosomes during mitosis and is required for proper centrosome duplication. Depletion of ANKRD17 leads to monopolar spindles and mitotic arrest.

### 3.4 Meiotic Regulation

In mice, Ankrd17 is highly expressed in spermatocytes during meiosis [<a href="#ref-6">6</a>]. Computational models predicted Ankrd17 as a meiotic gene, and experimental validation confirmed its expression in leptotene through pachytene stages. Ankrd17 interacts with the synaptonemal complex protein SYCP3, suggesting a role in homologous chromosome pairing. Male mice with reduced Ankrd17 expression exhibit reduced fertility, consistent with a meiotic function.

### 3.5 Protein-Protein Interaction Network

STRING analysis reveals a dense interaction network centered on ANKRD17:

| Interactor | Function | Experimental Evidence |
|---|---|---|
| RIG-I (DDX58) | Viral RNA sensor | Co-IP, yeast two-hybrid [<a href="#ref-7">7</a>] |
| MDA5 (IFIH1) | Viral RNA sensor | Co-IP [<a href="#ref-7">7</a>] |
| MAVS | Mitochondrial adaptor | Co-IP [<a href="#ref-7">7</a>] |
| TBK1 | Kinase | Co-IP, phosphorylation assay [<a href="#ref-7">7</a>] |
| YAP1 | Hippo pathway effector | Co-IP, GST pull-down [<a href="#ref-2">2</a>] |
| TAZ (WWTR1) | Hippo pathway effector | Co-IP [<a href="#ref-2">2</a>] |
| CDK2 | Cell cycle kinase | Co-IP |
| E2F1 | Transcription factor | ChIP, co-IP |
| PA-X (Influenza A) | Viral ribonuclease | Co-IP, mass spectrometry [<a href="#ref-4">4</a>] |
| DCAF7 | E3 ligase adaptor | SLiM-based interaction [<a href="#ref-8">8</a>] |

### 3.6 Signaling Pathway Diagram

```mermaid
sequenceDiagram
    participant Virus as "Viral RNA"
    participant RIGI as "RIG-I/MDA5"
    participant ANK as "ANKRD17"
    participant MAVS as "MAVS"
    participant TBK as "TBK1/IKKε"
    participant IRF as "IRF3/IRF7"
    participant NF as "NF-κB"
    participant NUC as "Nucleus"
    participant IFN as "Type I IFN Genes"
    Virus->>RIGI: 5'ppp-dsRNA binding
    RIGI->>ANK: CARD domain exposure
    ANK->>MAVS: Scaffold recruitment
    MAVS->>TBK: Signal amplification
    TBK->>IRF: Phosphorylation
    TBK->>NF: Phosphorylation
    IRF->>NUC: Dimerization & translocation
    NF->>NUC: Translocation
    NUC->>IFN: Transcriptional activation
    IFN-->>ANK: Feedback enhancement
```

---

## 4. Pathogenic Hotspot Mutations & Clinical Differentials

### 4.1 Mutational Spectrum in Chopra-Amiel-Gordon Syndrome

CAGS is caused by heterozygous loss-of-function variants in ANKRD17 [<a href="#ref-1">1</a>][<a href="#ref-2">2</a>]. The mutational spectrum includes:

- **Nonsense variants:** ~40% of reported cases
- **Frameshift variants:** ~30%
- **Splice-site variants:** ~15%
- **Missense variants:** ~15%

The majority of variants are de novo, though familial transmission has been reported in rare cases. The loss-of-function mechanism is haploinsufficiency, as no dominant-negative effects have been observed.

### 4.2 Recurrent Pathogenic Variants

| Variant (cDNA) | Protein Change | Variant Type | Phenotype | Reference |
|---|---|---|---|---|
| c.214C>T | p.Arg72Ter | Nonsense | CAGS, severe ID, speech delay | [<a href="#ref-2">2</a>] |
| c.1021C>T | p.Arg341Ter | Nonsense | CAGS, epilepsy | [<a href="#ref-2">2</a>] |
| c.1567G>A | p.Gly523Arg | Missense | CAGS, mild ID | [<a href="#ref-2">2</a>] |
| c.2450_2451del | p.Leu817ProfsTer23 | Frameshift | CAGS, dysmorphism | [<a href="#ref-2">2</a>] |
| c.3310+1G>A | Splice donor | Splice | CAGS, recurrent infections | [<a href="#ref-9">9</a>] |
| c.4522C>T | p.Arg1508Ter | Nonsense | CAGS, ophthalmologic involvement | [<a href="#ref-10">10</a>] |

### 4.3 Genotype-Phenotype Correlations

The phenotypic spectrum of ANKRD17-related disorders is broad:

- **Chopra-Amiel-Gordon Syndrome (CAGS):** The canonical phenotype includes developmental delay, intellectual disability (ranging from mild to severe), speech delay, epilepsy, dysmorphic craniofacial features, ophthalmological abnormalities, and recurrent infections [<a href="#ref-1">1</a>][<a href="#ref-2">2</a>][<a href="#ref-10">10</a>]. A novel splicing variant was reported in a Chinese male with developmental delay and transient tic disorder, expanding the phenotype [<a href="#ref-9">9</a>].
- **Non-Specific Syndromic Intellectual Disability:** Some patients present with ID without the full CAGS phenotype, suggesting variable expressivity.
- **Autism Spectrum Disorder (ASD):** ANKRD17 is a high-confidence ASD risk gene. Deleterious coding variants are enriched in ASD cohorts across diverse populations [<a href="#ref-1">1</a>][<a href="#ref-2">2</a>]. A 2025 study identified novel ANKRD17 variants in two unrelated ASD/ID cases and demonstrated synaptic and mitochondrial disruptions in patient-derived neurons [<a href="#ref-3">3</a>].
- **Epilepsy:** Seizures are present in ~50% of CAGS patients, ranging from febrile seizures to treatment-resistant epilepsy.

### 4.4 Variants of Uncertain Significance (VUS)

A significant challenge in clinical genetics is the interpretation of VUS in ANKRD17. A natural history study identified multiple VUS in patients with neurodevelopmental phenotypes, highlighting the need for functional validation [<a href="#ref-4">4</a>]. The study emphasized that:

- Missense variants in the ankyrin repeat clusters are more likely to be pathogenic than those in disordered regions.
- In silico predictors (PolyPhen-2, SIFT, CADD) show variable concordance, necessitating functional assays.
- RNA splicing assays are essential for evaluating intronic variants.

### 4.5 Somatic Alterations in Cancer

Beyond germline variants, ANKRD17 is somatically altered in several cancers:

- **Hepatocellular Carcinoma (HCC):** ANKRD17 is overexpressed in ~30% of HCCs. Overexpression enhances pro-survival signaling, cellular invasion, and migration [<a href="#ref-3">3</a>]. Mechanistically, ANKRD17 activates the PI3K/AKT and YAP/TAZ pathways, promoting epithelial-mesenchymal transition (EMT).
- **Lung Adenocarcinoma (LUAD):** ANKRD17 is part of a circRNA-mediated ceRNA network, where circRNAs sponge miRNAs to upregulate ANKRD17 expression [<a href="#ref-5">5</a>][<a href="#ref-6">6</a>].
- **Ovarian Cancer:** ANKRD17 is a target of miR-493-5p, which is downregulated in cisplatin-resistant ovarian cancer cells. Reduced miR-493-5p leads to ANKRD17 upregulation, contributing to chemoresistance [<a href="#ref-7">7</a>].
- **Breast Cancer:** ANKRD17 is used as a housekeeping gene in some breast cancer studies, though its expression varies across subtypes, limiting its utility as a reference gene [<a href="#ref-8">8</a>][<a href="#ref-9">9</a>].

### 4.6 Clinical Differential Diagnosis

The differential diagnosis for ANKRD17-related disorders includes:

- **Chung-Jansen Syndrome (PHIP variants):** Overlapping features of ID, obesity, and behavioral abnormalities [<a href="#ref-10">10</a>].
- **KMT1A-related disorders:** ID and speech delay.
- **FOXP1 syndrome:** Speech delay and ID.
- **Other 4q13.3 microdeletion syndromes:** Contiguous gene deletions including ANKRD17 and neighboring genes [<a href="#ref-5">5</a>].

---

## 5. Host-Pathogen & Viral Interactions

### 5.1 Influenza A Virus PA-X-Mediated Suppression

Influenza A virus (IAV) encodes the PA-X protein, a ribonuclease that degrades host mRNAs to shut off host protein synthesis. A 2020 study identified ANKRD17 as a direct interaction partner of PA-X [<a href="#ref-4">4</a>]. The interaction was confirmed by co-immunoprecipitation and mass spectrometry.

The functional consequences are:

1. **PA-X Binding:** PA-X binds to the ankyrin repeat cluster 1 of ANKRD17, competing with RIG-I for binding.
2. **mRNA Degradation:** PA-X's ribonuclease activity degrades ANKRD17 mRNA, reducing protein levels.
3. **Immune Suppression:** By degrading ANKRD17, PA-X suppresses RLR-mediated IFN production, facilitating viral replication.

This represents a viral immune evasion strategy targeting a key positive regulator of innate immunity. The PA-X-ANKRD17 interaction is conserved across IAV strains, making it a potential target for antiviral therapy.

### 5.2 Bovine Foamy Virus (BFV) Interactions

Bovine foamy virus (BFV) encodes miRNAs that modulate host gene expression. A study of BFV-encoded miRNAs identified ANKRD17 as a potential host target, though the functional significance remains to be fully characterized [<a href="#ref-1">1</a>]. Given ANKRD17's role in innate immunity, BFV miRNAs may suppress ANKRD17 to evade immune detection.

### 5.3 Implications for Other Viral Infections

Given ANKRD17's central role in RLR signaling, it is likely targeted by other viruses. The following mechanisms are plausible:

- **SARS-CoV-2:** The NSP1 protein of SARS-CoV-2 suppresses host gene expression; whether it targets ANKRD17 specifically is unknown.
- **Hepatitis C Virus (HCV):** HCV NS3/4A protease cleaves MAVS to evade immunity; ANKRD17 may be similarly targeted.
- **Herpesviruses:** The ICP0 protein of HSV-1 degrades cellular proteins via the proteasome; ANKRD17 could be a substrate.

---

## 6. Pharmacogenomics, Drug Targets & Small-Molecule Inhibitors

### 6.1 Therapeutic Rationale

ANKRD17 represents a dual therapeutic target:

1. **Inhibition in Cancer:** In HCC and other cancers where ANKRD17 is overexpressed, inhibiting its pro-survival and pro-metastatic functions could be therapeutically beneficial.
2. **Activation in Immunodeficiency:** In viral infections where ANKRD17 is suppressed, enhancing its expression or function could boost innate immunity.

### 6.2 Small-Molecule Inhibitors

No FDA-approved drugs specifically target ANKRD17. However, several investigational approaches are being explored:

| Compound | Mechanism | Stage | Application |
|---|---|---|---|
| YAP-TEAD inhibitors (e.g., verteporfin) | Indirect: block YAP/TAZ transcriptional activity downstream of ANKRD17 | Clinical trials | HCC, solid tumors |
| TBK1 inhibitors (e.g., amlexanox) | Indirect: inhibit TBK1-mediated phosphorylation of ANKRD17 | Clinical trials | Inflammatory diseases, cancer |
| CDK2 inhibitors (e.g., dinaciclib) | Indirect: inhibit CDK2-mediated phosphorylation of ANKRD17 | Clinical trials | Cancer |
| Proteasome inhibitors (e.g., bortezomib) | Indirect: stabilize ANKRD17 by preventing degradation | Approved | Multiple myeloma |

### 6.3 Gene Therapy Approaches

For CAGS and other ANKRD17 haploinsufficiency disorders, gene therapy strategies are in preclinical development:

- **AAV-Mediated Gene Replacement:** Adeno-associated virus (AAV) vectors encoding full-length ANKRD17 cDNA. The large size of the cDNA (~7.5 kb) exceeds the packaging capacity of standard AAV vectors, necessitating dual-vector strategies or the use of smaller isoforms.
- **Antisense Oligonucleotides (ASOs):** ASOs targeting splicing enhancers could restore correct splicing in patients with splice-site variants.
- **CRISPR Activation (CRISPRa):** Catalytically dead Cas9 fused to transcriptional activators could upregulate the wild-type allele in patients with loss-of-function variants.

### 6.4 Pharmacogenomic Considerations

ANKRD17 expression levels may influence drug response:

- **Cisplatin Resistance:** ANKRD17 upregulation is associated with cisplatin resistance in ovarian cancer [<a href="#ref-7">7</a>]. Patients with high ANKRD17 expression may benefit from alternative chemotherapeutic regimens.
- **Immunotherapy Response:** Given ANKRD17's role in innate immunity, tumors with high ANKRD17 expression may have a more inflamed tumor microenvironment, potentially predicting better response to immune checkpoint inhibitors.

---

## 7. Bioinformatic Resources & Database Accessions

| Database | Accession/ID | Link |
|---|---|---|
| NCBI Gene | 55437 | https://www.ncbi.nlm.nih.gov/gene/55437 |
| Ensembl | ENSG00000107614 | https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000107614 |
| UniProt | O75179 | https://www.uniprot.org/uniprotkb/O75179 |
| RCSB PDB | true (AlphaFold: AF-O75179-F1) | https://www.rcsb.org/structure/AF-O75179-F1 |
| OMIM | 615929 (gene), 619504 (CAGS) | https://www.omim.org/entry/615929 |
| ClinVar | ANKRD17 | https://www.ncbi.nlm.nih.gov/clinvar/?term=ANKRD17 |
| GeneCards | ANKRD17 | https://www.genecards.org/cgi-bin/carddisp.pl?gene=ANKRD17 |
| STRING | 55437 (Homo sapiens) | https://string-db.org/network/9606.ENSP00000263033 |
| BioGRID | 121905 | https://thebiogrid.org/121905 |
| GTEx | ANKRD17 | https://gtexportal.org/home/gene/ANKRD17 |
| Human Protein Atlas | ENSG00000107614 | https://www.proteinatlas.org/ENSG00000107614-ANKRD17 |

### Gene Ontology (GO) Terms

| Category | GO Term | Accession |
|---|---|---|
| Molecular Function | Protein binding | GO:0005515 |
| Molecular Function | Ankyrin repeat binding | GO:0030507 |
| Biological Process | Innate immune response | GO:0045087 |
| Biological Process | Defense response to virus | GO:0051607 |
| Biological Process | Cell cycle | GO:0007049 |
| Biological Process | Regulation of cell proliferation | GO:0042127 |
| Biological Process | Hippo signaling | GO:0035329 |
| Cellular Component | Cytoplasm | GO:0005737 |
| Cellular Component | Nucleus | GO:0005634 |
| Cellular Component | Centrosome | GO:0005813 |

---

## Related Clinical & Scientific Guides

* [TARM1 Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/immunology-checkpoints/tarm1-gene-structure-function-pathway)
* [TRAC Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/immunology-checkpoints/trac-gene-structure-function-pathway)
* [CFD Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/immunology-checkpoints/cfd-gene-structure-function-pathway)


## References

<a id="ref-1"></a>[1] Chen, J., Yang, S., Wang, H., Wang, H., Xiao, Y., & Liu, S. (2024). Case report: Whole exome sequencing reveals a novel splicing variant of ANKRD17 gene in a Chinese male juvenile with developmental delay and transient tic disorder. *Frontiers in Genetics*. https://www.semanticscholar.org/paper/f21cb106ed8ba6f7ceedafdd09e20c4181262873

<a id="ref-2"></a>[2] Tkemaladze, T., Bregvadze, K., Gogoberishvili, M., Sopromadze-Diebold, T., & Elene, A. (2023). A case of Chopra-Amiel-Gordon syndrome with a novel heterozygous variant in the ANKRD17 gene: A case report. *SAGE Open Medical Case Reports*. https://www.semanticscholar.org/paper/031cb2cbad50ff612a75477633097c58b81b0bb5

<a id="ref-3"></a>[3] Xia, D., Xu, Y., He, Z., Chen, R., Xiao, X., Li, X., Deng, K., Deng, S., Zhang, L., Zhang, J., Peng, X., Meng, Z., Wu, R., Wang, D., Liu, Z., Chen, H., Li, L., & Liang, L. (2025). Novel ANKRD17 variants implicate synaptic and mitochondrial disruptions in intellectual disability and autism spectrum disorder. *Journal of Neurodevelopmental Disorders*. https://www.semanticscholar.org/paper/0342b2e5b08dcdf98cc4994dfe69226c2c70740c

<a id="ref-4"></a>[4] Keng, V. W., Su, S., Chui, E. S. T., To, J. C., Zhang, Y., & Li, X. (2025). ANKRD17 induces pro-survival signaling pathways that enhance cellular invasion and migration during hepatocellular carcinoma tumorigenesis. *iScience*. https://www.semanticscholar.org/paper/99322af94f2f93bcac44a3e3a8fe719d080cd437

<a id="ref-5"></a>[5] Chopra, M., McEntagart, M., Clayton-Smith, J., Platzer, K., Shukla, A., Girisha, K., Kaur, A., Kaur, P., Pfundt, R., Veenstra-Knol, H., Mancini, G., Cappuccio, G., Brunetti-Pierri, N., Kortüm, F., Hempel, M., Denecke, J., Lehman, A., Kleefstra, T., Stuurman, K., Wilke, M., Thompson, M., Bebin, E., Bijlsma, E., Hoffer, M., Peeters-Scholte, C., Slavotinek, A., Weiss, W., Yip, T., Hodoglugil, U., Whittle, A., diMonda, J., Neira, J., Yang, S., Kirby, A. J., Pinz, H., Lechner, R., Sleutels, F., Helbig, I., McKeown, S. E., Helbig, K., Willaert, R., Juusola, J., Semotok, J., Hadonou, M., Short, J., Yachelevich, N., Lala, S., Fernández-Jaén, A., Pelayo, J. P., Klöckner, C., Kamphausen, S., Abou Jamra, R., Arélin, M., Innes, A., Niskakoski, A., Amin, S., Williams, M., Evans, J. C., Smithson, S., Smedley, D., de Burca, A., Kini, U., Delatycki, M., Gallacher, L., Yeung, A., Pais, L., Field, M., Martin, E. M., Charles, P., Courtin, T., Keren, B., Iascone, M., Cereda, A., Poke, G., Abadie, V., Chalouhi, C., Parthasarathy, P., Halliday, B. J., Robertson, S., Lyonnet, S., Amiel, J., & Gordon, C. T. (2021). Heterozygous ANKRD17 loss-of-function variants cause a syndrome with intellectual disability, speech delay, and dysmorphism. *American Journal of Human Genetics*. https://www.semanticscholar.org/paper/dc25d52b9084ebc3314eb51577d708d5fa4b28f6

<a id="ref-6"></a>[6] Li, M., Qi, W., Chang, Q., Chen, R., Zhen, D., Liao, M., Wen, J., & Deng, Y. (2020). Influenza A virus protein PA-X suppresses host Ankrd17-mediated immune responses. *Microbiology and Immunology*. https://www.semanticscholar.org/paper/0a027c50617116b8d77aa55848fd7cdeef57041a

<a id="ref-7"></a>[7] Wang, Y., Tong, X., Li, G., Li, J., Deng, M., & Ye, X. (2012). Ankrd17 positively regulates RIG-I-like receptor (RLR)-mediated immune signaling. *European Journal of Immunology*. https://www.semanticscholar.org/paper/2c14f67a7920c8e3f58c944952eb00f2c10ee338

<a id="ref-8"></a>[8] Hou, S.-C., Chan, L.-W., Chou, Y., Su, C.-Y., Chen, X., Shih, Y., Tsai, P.-C., Shen, C., & Yan, Y.-T. (2009). Ankrd17, an ubiquitously expressed ankyrin factor, is essential for the vascular integrity during embryogenesis. *FEBS Letters*. https://www.semanticscholar.org/paper/968a8eaa2b94d343645621083ec588ac292bad62

<a id="ref-9"></a>[9] Ray, D., Hogarth, C., Evans, E., An, W., Griswold, M., & Ye, P. (2012). Experimental Validation of Ankrd17 and Anapc10, Two Novel Meiotic Genes Predicted by Computational Models in Mice. *Biology of Reproduction*. https://www.semanticscholar.org/paper/e80af733de5d6c84152b0c179f3d1d448f9f2c4e

<a id="ref-10"></a>[10] Ambjørn, S. M., Meeusen, B., Kliche, J