GADD45B (Growth Arrest and DNA Damage Inducible Beta) is a stressresponsive gene that plays critical roles in DNA repair, cell cycle arrest, apoptosis, and neuronal survival. It is induced by various cellular stresses including oxidative stress, DNA damage, and excitotoxicity in the brain. [1]
| Gene Information | |
|---|---|
| Symbol | GADD45B |
| Full Name | Growth Arrest and DNA Damage Inducible Beta |
| Chromosome | 19p13.3 |
| NCBI Gene ID | 10988 |
| OMIM | 604411 |
| UniProt ID | Q9ULLI |
| Ensembl ID | ENSG00000099899 |
GADD45B encodes a small acidic protein (~165 amino acids) that belongs to the GADD45 family of stress-responsive proteins, which also includes GADD45A and GADD45G. These proteins are key sentinels of cellular stress and function as molecular bridges between stress signals and downstream effector pathways.
GADD45B participates in several critical cellular processes:
DNA Repair: GADD45B facilitates base excision repair (BER) and nucleotide excision repair (NER) by interacting with proliferating cell nuclear antigen (PCNA) and AP endonuclease (APE1). This function is critical for maintaining genomic integrity in post-mitotic neurons that cannot undergo cell division. [1:1]
Cell Cycle Control: GADD45B induces G2/M cell cycle arrest through p53-independent pathways, preventing DNA-damaged cells from proceeding through the cell cycle.
Stress-Activated Signaling: GADD45B interacts with key signaling molecules including p38 MAPK, JNK, and nuclear factor kappa B (NF-κB), integrating stress signals into cellular responses. [1:2]
Apoptosis Regulation: GADD45B can be pro-apoptotic or anti-apoptotic depending on context, acting as a rheostat for cell survival decisions under stress.
Synaptic Plasticity: Emerging evidence suggests GADD45B participates in activity-dependent synaptic remodeling.
GADD45B is induced in brain in response to cellular stress, ischemia, and neurodegenerative stimuli. In the brain, expression is detected in:
Expression is tightly regulated by p53 and other stress-responsive transcription factors.
GADD45B is upregulated in AD brain as a response to amyloid-beta (Aβ) toxicity. The upregulation represents a neuroprotective stress response attempting to repair Aβ-induced DNA damage and maintain neuronal survival. However, chronic elevation may contribute to neuronal dysfunction.
| Association | Mechanism |
|---|---|
| Aβ-induced stress response | DNA damage repair pathway activation |
| Neuronal apoptosis | p53-dependent pathways |
| synaptic dysfunction | Stress-activated kinase pathways |
GADD45B plays complex roles in dopaminergic neuron survival. In PD, the substantia nigra shows altered GADD45B expression in response to oxidative stress from dopamine metabolism and environmental toxins. Ravel-Godreuil et al. (2021) demonstrated that perturbed DNA methylation by GADD45b induces chromatin disorganization and dopaminergic neuron death, suggesting a dual role in both protection and pathogenesis. [2]
| Association | Mechanism |
|---|---|
| Oxidative stress response | Dopamine metabolism byproducts |
| Dopaminergic neuron death | p53-dependent apoptosis |
| Alpha-synuclein pathology | Altered stress response gene expression [3] |
GADD45B is highly induced after ischemic brain injury. Cho et al. (2019) demonstrated that Gadd45b acts as a neuroprotective effector in global ischemia-induced neuronal death, with knock-down exacerbating neuronal loss. This makes GADD45B a potential therapeutic target for stroke intervention. [1:3]
| Association | Mechanism |
|---|---|
| Ischemic preconditioning | Stress adaptation |
| Neuronal death/survival | Pro-/anti-apoptotic balance |
| Neural repair | DNA repair and neurogenesis |
GADD45B expression is altered in motor neuron disease, potentially reflecting the widespread stress response in ALS pathology.
GADD45B promotes DNA repair through:
GADD45B integrates multiple stress signals:
Recent research identified a novel pathway where GADD45B activates MKK7, which then activates JNK and p21, leading to cell cycle arrest. This pathway is relevant for understanding neurodevelopmental toxicity. [4]
GADD45B is an attractive therapeutic target because:
| Approach | Status | Notes |
|---|---|---|
| Gene therapy | Preclinical | AAV-mediated GADD45B delivery |
| Small molecule activators | Discovery | Compounds to boost GADD45B expression |
| CRISPR activation | Research | Epigenetic upregulation |
GADD45B's dual role in both protecting neurons and potentially contributing to pathology makes it a complex therapeutic target. Current strategies being explored include:
Gene Therapy Approaches: Viral vector delivery of GADD45B to enhance DNA repair capacity in neurons. AAV-based delivery systems are being optimized to target specific brain regions affected in neurodegenerative diseases.
Small Molecule Modulators: Compounds that can selectively modulate GADD45B expression or activity. These include:
Several challenges complicate therapeutic development:
GADD45B expression levels in:
could serve as biomarkers for disease progression and treatment response.
Preclinical studies in various models have shown:
The GADD45B gene (also known as MYD18) is located on chromosome 19p13.3 and consists of 4 exons. It encodes a 160-amino acid protein with a molecular weight of approximately 18 kDa.
GADD45B belongs to the GADD45 family, which shares conserved motifs involved in:
GADD45B activity is regulated by multiple post-translational modifications:
GADD45B serves as a hub for multiple stress-activated signaling pathways:
GADD45B interacts with GADD45A and GADD45G to coordinate stress responses:
The family members can compensate for each other to some degree, making single knockout mice viable.
GADD45B expression can serve as:
Currently, no clinical trials specifically target GADD45B. However, several trials targeting related pathways may affect GADD45B expression:
Cho CH, et al. (2019). Gadd45b Acts as Neuroprotective Effector in Global Ischemia-Induced Neuronal Death. J Neurosci Res. 2019. ↩︎ ↩︎ ↩︎ ↩︎
Ravel-Godreuil C, et al. (2021). Perturbed DNA methylation by Gadd45b induces chromatin disorganization, DNA strand breaks and dopaminergic neuron death. Acta Neuropathol Commun. 2021. ↩︎
Motyl J, et al. (2018). Alpha-synuclein alters differently gene expression of Sirts, PARPs and other stress response proteins. J Mol Neurosci. 2018. ↩︎
Tang H, et al. (2026). Bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate Induces Neurodevelopmental Toxicity through the Gadd45b-MKK7-p21 Pathway. Chemosphere. 2026. ↩︎