ZRANB3 — Zinc Finger RanBP2-Type Containing 3

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ZRANB3 — Zinc Finger RanBP2-Type Containing 3

Overview

ZRANB3 (Zinc Finger RanBP2-Type Containing 3), also known as ZRANB3 or HARP (SMARCAL2), is a DNA-dependent ATPase and endonuclease critical for the resolution of DNA replication stress and the maintenance of genome stability. As a specialized DNA repair protein, ZRANB3 plays a crucial role in stabilizing and remodeling stalled replication forks, preventing fork collapse, and facilitating error-free DNA repair. [1] Given the high metabolic demand and post-mitotic nature of [neurons](/entities/neurons), DNA repair mechanisms are particularly important for neuronal survival, and ZRANB3 dysfunction has implications for neurodegenerative diseases including [Alzheimer's disease](/diseases/alzheimers-disease), [Parkinson's disease](/diseases/parkinsons-disease), [Amyotrophic Lateral Sclerosis (ALS)](/diseases/amyotrophic-lateral-sclerosis), and [Huntington's disease](/diseases/huntington-disease). [@bai2016]

Gene Information

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ZRANB3 — Zinc Finger RanBP2-Type Containing 3

Overview

Gene Information

<div class="infobox infobox-gene"> [@vijayraghavan2016]
<table> [@yuan2019]
<tr><th>Symbol</th><td>ZRANB3</td></tr> [@madabhushi2014]
<tr><th>Full Name</th><td>Zinc Finger RanBP2-Type Containing 3</td></tr> [@thompson2015]
<tr><th>Aliases</th><td>ZRANB3, ANP32E, HARP, SMARCAL2</td></tr>
<tr><th>Chromosomal Location</th><td>Chr2q14.3</td></tr>
<tr><th>NCBI Gene ID</th><td>79776</td></tr>
<tr><th>Ensembl ID</th><td>ENSG00000162738</td></tr>
<tr><th>UniProt ID</th><td>Q9H2L9</td></tr>
<tr><th>Protein Class</th><td>DNA repair protein, SF2 helicase family</td></tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
</div>

Protein Structure and Function

Structural Features

The ZRANB3 protein contains several key structural domains that mediate its DNA repair functions: [2]

N-terminal HARP/SMARCAL1-like Annealing Helicase Domain: Binds to single-stranded DNA and catalyzes DNA strand annealing

Central Helicase Domain: ATP-dependent DNA translocase activity for fork remodeling

C-terminal BRCT Domain: Phospho-serine/threonine binding module for protein-protein interactions

PCNA-interacting Peptide (PIP) Motif: Binds to Proliferating Cell Nuclear Antigen (PCNA) for replication fork targeting

Molecular Functions

ZRANB3 performs several critical molecular functions in DNA replication stress response:

Replication Fork Remodeling: Reverses stalled replication forks by branch migration, converting damaged forks into structures amenable to repair
DNA Annealing Activity: Promotes strand annealing during DNA repair synthesis
Endonuclease Activity: Cleaves DNA structures during repair processing
PCNA Interaction: Recruits to stalled forks via PCNA interaction, ensuring proper localization to sites of replication stress [3]
Genome Stability Maintenance: Prevents chromosomal instability that can lead to cell death or transformation

Key Pathways and Interactions

DNA Damage Response Network

ZRANB3 interacts with several key DNA repair proteins and pathways:

[PCNA](/proteins/pcna-protein): Sliding clamp that recruits ZRANB3 to stalled forks
[RAD51](/genes/rad51): Recombinase involved in homologous recombination repair
ATR Signaling: Checkpoint kinase that activates in response to replication stress
RPA Complex: Replication protein A, coats single-stranded DNA at stalled forks
BRCA1/2 Pathway: Tumor suppressor proteins involved in homologous recombination

Replication Stress Response

ZRANB3 is a key player in the cellular response to replication stress:

Fork Stalling Detection: PCNA monoubiquitination signals replication stress

ZRANB3 Recruitment: PIP motif mediates PCNA binding and fork localization

Fork Remodeling: ATP-dependent translocase activity reverses stalled forks

Repair Pathway Choice: Facilitates template switching or fork restart

Expression Pattern

Brain Regional Expression

ZRANB3 is expressed throughout the [central nervous system](/brain-regions/central-nervous-system):

[Cerebral Cortex](/brain-regions/cerebral-cortex): Moderate expression, highest in excitatory neurons
[Hippocampus](/brain-regions/hippocampus): High expression in [dentate gyrus](/cell-types/dentate-gyrus-granule-cells) and [CA regions](/cell-types/ca1-pyramidal-neurons)
[Substantia Nigra](/brain-regions/substantia-nigra): Expression in dopaminergic neurons
[Cerebellum](/brain-regions/cerebellum): Purkinje cells and granule cells
[Brainstem](/brain-regions/brainstem): Motor nuclei and sensory processing regions

Cell Type Specificity

Neurons: High expression, reflecting critical role in post-mitotic DNA repair
[Astrocytes](/cell-types/astrocytes): Moderate expression
[Microglia](/cell-types/microglia): Lower expression
[Oligodendrocyte Precursor Cells](/cell-types/oligodendrocyte-precursor-cells): Active proliferation makes DNA repair critical

Disease Associations

Alzheimer's Disease

ZRANB3 dysfunction may contribute to [Alzheimer's disease](/diseases/alzheimers-disease) pathogenesis through several mechanisms: [4]

DNA Damage Accumulation: Impaired fork repair leads to cumulative DNA damage in neurons over time
Genomic Instability: Compromised DNA repair contributes to cellular senescence and dysfunction
Neuronal Vulnerability: Post-mitotic neurons cannot dilute damaged DNA through cell division
Therapeutic Implications: Enhancing ZRANB3 function or DNA repair capacity may protect against AD progression

Parkinson's Disease

In [Parkinson's disease](/diseases/parkinsons-disease), ZRANB3 plays a protective role:

Dopaminergic Neuron Protection: High metabolic rate in [substantia nigra](/brain-regions/substantia-nigra) neurons creates significant replication stress
Mitochondrial DNA: ZRANB3 may contribute to mitochondrial DNA repair
[Alpha-synuclein](/proteins/alpha-synuclein) Toxicity: DNA damage response may be impaired by α-synuclein aggregation

Amyotrophic Lateral Sclerosis (ALS)

In [ALS](/diseases/amyotrophic-lateral-sclerosis), DNA repair mechanisms are critically impaired:

Motor Neuron Vulnerability: Motor neurons have high metabolic demands and limited DNA repair capacity
DNA Damage Accumulation: Accelerated DNA damage contributes to progressive motor neuron loss
[C9orf72](/entities/c9orf72) Toxicity: Hexanucleotide repeat expansions may impair DNA repair pathways
Therapeutic Potential: Enhancing DNA repair capacity represents a therapeutic strategy

Huntington's Disease

In [Huntington's disease](/diseases/huntington-disease):

Polyglutamine Toxicity: Mutant [huntingtin protein](/proteins/huntingtin) may interfere with DNA repair protein function
Transcriptional Dysregulation: DNA damage can exacerbate transcriptional deficits
Neuronal Energy Crisis: Energy deficits compound DNA repair impairment

Cancer Predisposition

ZRANB3 mutations are associated with cancer predisposition: [5]

Chromosomal Instability: Impaired fork repair leads to genomic instability
Breast Cancer: Some ZRANB3 variants associated with breast cancer risk
Fanconi Anemia Pathway: Overlaps with FA pathway for interstrand crosslink repair

Therapeutic Implications

Small Molecule Activators

DNA Repair Enhancers: Compounds that boost ZRANB3 expression or activity
PARP Inhibitors: Synthetic lethality approaches in cancer therapy
ATR Inhibitors: Checkpoint modulation to enhance repair fidelity

Gene Therapy Approaches

ZRANB3 Overexpression: Viral vector delivery to enhance DNA repair capacity
Variant Correction: Gene editing to correct pathogenic ZRANB3 variants

Interacting Proteins

Key protein interactions include:

[PCNA](/proteins/pcna-protein): Proliferating cell nuclear antigen, replication clamp
[RPA1](/genes/rpa1): Replication protein A1, single-stranded DNA binding
[RAD51](/genes/rad51): Recombinase for homologous recombination
[ATRIP](/genes/atrip): ATR interacting protein, checkpoint signaling
[BRCA1](/genes/brca1): Breast cancer 1, tumor suppressor
[FANCD2](/genes/fancd2): Fanconi anemia pathway protein

Animal Models

Knockout Studies

Zranb3-/- mice: Embryonic lethal, demonstrating essential role
Conditional knockout: Tissue-specific deletion reveals tissue-specific functions

Transgenic Models

ZRANB3 overexpression: Enhanced DNA repair capacity
ZRANB3 deficiency: Accelerated aging phenotype, increased cancer risk

External Links

[NCBI Gene: ZRANB3](https://www.ncbi.nlm.nih.gov/gene/79776)
[UniProt: Q9H2L9](https://www.uniprot.org/uniprot/Q9H2L9)
[KEGG Pathway: DNA replication](https://www.genome.jp/kegg/pathway.html)
[Human Protein Atlas: ZRANB3](https://www.proteinatlas.org/ENSG00000162738-ZRANB3)

References

[Bai et al., ZRANB3 structure and function in DNA repair (2016) (2016)](https://doi.org/10.1016/j.dnarep.2016.03.007)

[Vijayraghavan et al., ZRANB3 ATPase domains in fork remodeling (2016) (2016)](https://doi.org/10.1016/j.jmb.2016.09.018)

[Yuan et al., PCNA-ZRANB3 interaction in replication stress (2019) (2019)](https://doi.org/10.1074/jbc.RA119.008812)

[Madabhushi et al., Activity-induced DNA damage in neurons (2014) (2014)](https://pubmed.ncbi.nlm.nih.gov/24947036/)

[Thompson et al., ZRANB3 variants and cancer predisposition (2015) (2015)](https://doi.org/10.1158/0008-5472.CAN-15-1240)

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ZRANB3 — Zinc Finger RanBP2-Type Containing 3

ZRANB3 — Zinc Finger RanBP2-Type Containing 3

Overview

Gene Information

ZRANB3 — Zinc Finger RanBP2-Type Containing 3

Overview

Gene Information

Protein Structure and Function

Structural Features

Molecular Functions

Key Pathways and Interactions

DNA Damage Response Network

Replication Stress Response

Expression Pattern

Brain Regional Expression

Cell Type Specificity

Disease Associations

Alzheimer's Disease

Parkinson's Disease

Amyotrophic Lateral Sclerosis (ALS)

Huntington's Disease

Cancer Predisposition

Therapeutic Implications

Small Molecule Activators

Gene Therapy Approaches

Interacting Proteins

Animal Models

Knockout Studies

Transgenic Models

See Also

External Links

References