EP300
EP300 encodes p300, a master transcriptional co-activator and histone acetyltransferase essential for gene expression and DNA repair. It acts as a central hub for thousands of interactions, linking metabolic signals to the epigenetic landscape and maintaining cellular youth through the stabilization of tumor suppressors like p53.
Key Takeaways
- •p300 is the "master scribe" that opens up DNA for reading.
- •It is a histone acetyltransferase (HAT) that adds acetyl marks to relax chromatin.
- •p300 is a critical cofactor for p53, enabling the response to DNA damage.
- •Age-related declines in p300 activity are linked to the global loss of epigenetic precision.
Basic Information
- Gene Symbol
- EP300
- Full Name
- E1A Binding Protein P300
- Also Known As
- p300KAT3BRSTS2
- Location
- 22q13.2
- Protein Type
- HAT / Coactivator
- Protein Family
- p300/CBP family
Related Isoforms
Key SNPs
Marker associated with variations in EP300 expression and studied in the context of neurodevelopmental and metabolic traits.
Common marker used in GWAS panels to identify the EP300 locus and its association with biological age and cognitive aging.
Overview
EP300 (E1A Binding Protein P300) encodes the protein p300, a massive and highly versatile transcriptional co-activator. Located in the cell nucleus, p300 acts as a central hub for the cell’s communication network. It does not bind to DNA directly; instead, it provides a physical platform where hundreds of different transcription factors (like p53, NF-κB, and nuclear receptors) meet to coordinate gene expression.
The primary enzymatic function of p300 is its histone acetyltransferase (HAT) activity. By attaching acetyl groups to the tails of histones, p300 neutralizes their positive charge, causing the tightly wound DNA to relax and open up. This "chromatin opening" is the prerequisite for almost all active gene expression. In the context of longevity, p300 is essential for the rapid activation of stress-response and repair genes, making it a cornerstone of cellular resilience and epigenetic maintenance.
Conceptual Model
A simplified mental model for the pathway:
p300 ensures the cell can access the "repair manuals" in its genetic library when needed.
Core Health Impacts
- • Epigenetic Maintenance: The primary enzyme responsible for the global patterns of histone acetylation required for gene access
- • DNA Damage Response: Essential cofactor for p53 and BRCA1 in the coordination of genomic repair
- • Cellular Differentiation: Master regulator of the gene programs that turn stem cells into specialized tissues
- • Immune Calibration: Coordinates the inflammatory response by serving as a hub for NF-κB and STAT signaling
- • Metabolic Flexibility: Links nutrient status to the genome by using Acetyl-CoA as the substrate for its reaction
Protein Domains
HAT Domain
The catalytic engine that transfers acetyl groups from Acetyl-CoA to histone tails.
KIX Domain
A versatile binding surface that captures transcription factors like CREB and MyoD.
Bromodomain
A specialized "reader" domain that recognizes existing acetyl marks to target p300 to active genes.
Upstream Regulators
Acetyl-CoA Activator
The definitive substrate; levels of this metabolic intermediate dictate the total "ink" available for p300.
AMPK Modulator
Energy sensor that can phosphorylate p300 to modulate its activity in response to nutrient scarcity.
SIRT1 Inhibitor
The primary antagonist; SIRT1 removes the acetyl marks that p300 adds, creating a dynamic balance.
Viral Oncoproteins Inhibitor
Proteins like Adenovirus E1A bind and hijack p300 to reprogram the cell for viral replication.
Downstream Targets
Histone Acetylation (H3K27ac) Activates
The primary biochemical output; relaxes chromatin to enable gene expression.
TP53 (p53) Activates
p300 acetylates p53 to stabilize it and increase its affinity for DNA repair genes.
MYC Activates
Recruits p300 to open up promoters for rapid cell growth and division.
GATA Factors Activates
Essential developmental transcription factors that rely on p300 for their full activity.
NF-κB Activates
Uses p300 as a platform to turn on pro-inflammatory and survival genes during injury.
Role in Aging
EP300 is a central node in the "epigenetic decay" of aging. As we age, the availability of its substrate (Acetyl-CoA) and the precision of its recruitment decline, leading to a state where the cell can no longer "unlock" the repair and maintenance genes needed for longevity.
Chromatin Stiffening
Aging involves a global loss of p300-mediated histone acetylation, making the genome less "flexible" and harder to read.
Repair Failure
Age-related declines in p300-p53 interaction reduce the body's ability to accurately fix DNA damage over time.
Metabolic Desynchrony
Changes in Acetyl-CoA levels with age directly impact p300 activity, linking dietary quality to epigenetic precision.
Inflammaging Hub
Dysregulated p300 activity in immune cells contributes to the "leaky" transcriptional control of chronic inflammation.
Stem Cell Reserve
Proper p300 function is a requirement for the maintenance and healthy differentiation of adult stem cell pools.
Longevity Modifier
Individuals with genetic variants that support robust p300 activity are being studied for their superior preservation of tissue architecture.
Disorders & Diseases
Rubinstein-Taybi Syndrome 2
Caused by germline mutations in EP300. Characterized by intellectual disability, growth delay, and distinct physical features.
Cancer (Loss of Function)
In many solid tumors, EP300 acts as a tumor suppressor; its mutation prevents the p53-mediated response to damage.
Acute Myeloid Leukemia
Chromosomal translocations involving EP300 create fusion proteins that drive uncontrolled blood cell growth.
Type 2 Diabetes
Dysregulated p300 activity in the liver contributes to the inappropriate production of glucose in insulin resistance.
Alzheimer’s Disease
Age-related loss of p300-mediated acetylation in the hippocampus is associated with synaptic failure and memory loss.
The Acetyl-CoA Bottleneck
p300 taught us that your DNA is only as "open" as your metabolism allows. Because p300 uses Acetyl-CoA as its fuel, it is the definitive link between the food you eat and the state of your chromatin. High-quality metabolic health is a prerequisite for the epigenetic youth that p300 provides.
Interventions
Supplements
May support the pool of Acetyl-CoA needed for p300 to perform its essential histone acetylation duties.
Sirtuin activator that works in a "tug-of-war" with p300 to ensure the epigenetic landscape is dynamic and clean.
The VDR pathway requires p300 as a mandatory coactivator to turn on its longevity-promoting genes.
Reported to be a natural inhibitor of p300 HAT activity, which is studied for its anti-cancer potential but may impact repair.
Lifestyle
Optimizes the Acetyl-CoA and SIRT1 balance, ensuring that p300 activity is focused on repair rather than overgrowth.
Triggers the metabolic surges that "exercise" the p300-mediated epigenetic remodeling pathways.
Ensures the steady supply of cofactors needed for the high-turnover protein environment where p300 works.
Minimizing exposure to carcinogens reduces the burden on the p300-p53 genomic maintenance machinery.
Medicines
Experimental drugs used in oncology to shut down the p300-mediated growth signals in certain lymphomas.
Modulate the balance of acetylation by increasing the "off-switch" that counteracts p300.
Compensate for low p300 activity by blocking the removal of acetyl marks, helping to "re-open" the genome.
Supports the metabolic environment (via AMPK) that regulates the efficiency of the p300 hub.
Lab Tests & Biomarkers
Epigenetic Status
Research marker that measures the global distribution of "active" DNA marks created by p300.
A biopsy test that reflects the total "openness" of the genome and the overall activity of the p300 scribe.
Genetic Screening
The definitive test for Rubinstein-Taybi Syndrome and a key component of comprehensive cancer NGS panels.
Assesses common variants linked to variations in neurodevelopmental and metabolic reserve.
Metabolic Context
An indirect measure of the substrate availability for the p300-mediated epigenetic response.
High levels can disrupt the precision of the p300hub, favoring growth over repair.
Hormonal Interactions
Estrogen Primary Co-Activator
The estrogen receptor (ER) requires p300 to unlock its target genes in bone and neural tissue.
Glucocorticoids Modulator
Stress hormones compete for p300 binding, potentially "stealing" the coactivator away from repair genes.
Thyroid Hormone (T3) Upregulator
Sets the metabolic rate of the liver and brain, impacting the turnover and activity of the p300 machinery.
Growth Hormone Synergist
Supports the systemic environment that allows for high-fidelity gene expression and organ maintenance.
Deep Dive
Network Diagrams
p300 and the Opening of the Genome
The Molecular Hub: p300 and the Scribe Team
To understand EP300 (the protein p300), one must view the cell nucleus as a massive construction project. While many genes provide the labor, p300 is the master coordinator. It is a massive protein that provides a physical meeting place for hundreds of other workers.
The Assembly Platform: p300 does not bind to DNA directly. Instead, it is a “coactivator.” It acts like a molecular magnet, pulling together diverse transcription factors like p53 (for repair), NF-κB (for immunity), and Estrogen (for growth). By bringing these workers together at the right spot on the genome, p300 ensures that the complex instructions for life are executed with perfect timing.
The Keymaker: Beyond its role as a hub, p300 has a specialized tool: its HAT domain. This domain adds “acetyl” marks to the protein spools (histones) that DNA is wrapped around. These marks act like a key, causing the spools to relax and “open up” the DNA so it can be read. Without p300 to make these keys, the genome remains locked, and the cell can no longer turn on its vital survival and repair programs.
The p53 Connection: The Handshake of Survival
The most important relationship in human cell biology is between p300 and p53, the guardian of the genome.
The Stabilization Step: When your DNA is damaged, p53 rushes to the scene. But p53 is unstable and short-lived. To work, it must find and bind to p300.
- The Handshake: p300 attaches acetyl groups to p53, which acts like a biological glue, stabilizing the protein and allowing it to stay at the DNA longer.
- The Result: This stabilized p53 can then recruit p300 to “open up” the specific repair genes needed to fix the damage. In cancers where p300 is mutated, this handshake fails—even if p53 is normal, it can no longer “open the books” to fix the cell, leading to the rapid accumulation of mutations that characterize biological aging and tumor growth.
The Metabolism-Epigenetics Link: Acetyl-CoA
A vital fact about p300 is that it is a nutrient sensor. It is the primary bridge between the food you eat and the way your genes are read.
The Ink of the Genome: To perform its job of opening up DNA, p300 requires a fuel called Acetyl-CoA. This molecule is produced during the breakdown of fats, sugars, and proteins.
- Metabolic Feedback: If your cellular energy is low, your Acetyl-CoA falls, and your p300 “scribe” runs out of ink. Your DNA remains tightly wound and difficult to read.
- Aging and Energy: This is one of the primary reasons why aging is associated with metabolic failure. As our mitochondria become less efficient, our Acetyl-CoA levels drop, and our p300 scribe stops working. Maintaining youthful metabolic flexibility—through diet and exercise—is the definitive way to ensure your p300 hub has the fuel it needs to keep your genetic library open and functional for life.
Practical Note: The Metabolic Hub
Your DNA is as open as your energy. p300 is an enzyme that uses a molecule called Acetyl-CoA as its ink. Acetyl-CoA is made from the food you eat. If your metabolism is broken (insulin resistance), your Acetyl-CoA levels are mis-timed, and your p300 cannot correctly "unlock" your DNA. High-quality metabolic health is the definitive prerequisite for the epigenetic precision that p300 provides.
The Stress Thief. In times of chronic high stress, the cortisol receptor "steals" p300 away from your repair and immunity genes. This is the molecular reason why long-term stress makes you age faster and get sick more often—your "repair scribes" are too busy responding to stress signals to maintain the rest of your genome.
Relevant Research Papers
Links go to PubMed (abstracts are public); some papers also offer free full text via PMC or the publisher.
A foundational review detailing the molecular architecture of p300 and its role as a universal hub for transcription.
Proved that p300 is the mandatory partner for p53, establishing its role as a master regulator of genomic stability.
Demonstrated that age-related declines in histone acetylation via p300 are a primary cause of cognitive failure.
Provided the first high-resolution crystal structure of the catalytic engine of p300, explaining its metabolic sensitivity.
Identified the clinical consequences of p300 deficiency in humans, defining its role in development and neural health.