DAGLB

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DAGLB

Overview

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">DAGLB</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>DAGLB</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Diacylglycerol Lipase Beta</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>7q31.1</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>27143</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000153048</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>Q8WWS3</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>672 amino acids</td>
</tr>
<tr>
<td class="label">Protein Class</td>
<td>Serine hydrolase, lipid hydrolase</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

DAGLB (Diacylglycerol Lipase Beta) encodes the enzyme diacylglycerol lipase beta (DAGL-β), which plays a critical role in the biosynthesis of the endocannabinoid [2-arachidonoylglycerol](/mechanisms/endocannabinoid-signaling) (2-AG)[@stella1997]. DAGL-β is one of two diacylglycerol lipase enzymes (along with DAGLA) responsible for converting diacylglycerol (DAG) into 2-AG, the most abundant endogenous cannabinoid in the brain[@ohno2014]. This enzymatic pathway is essential for endocannabinoid-mediated retrograde signaling at synapses throughout the central nervous system.

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DAGLB

Overview

The DAGLB gene is highly expressed in brain regions involved in learning, memory, and motor control, including the [hippocampus](/brain-regions/hippocampus), [cortex](/brain-regions/cortex), [basal ganglia](/brain-regions/basal-ganglia), and [cerebellum](/brain-regions/cerebellum)[@mechoulam2006]. Recent genetic studies have implicated DAGLB variants in neurodegenerative diseases, including Parkinson's disease and cerebellar ataxias[@keeer2019][@presburger2019].

Gene Information

Molecular Function

Enzymatic Activity

DAGL-β is a membrane-bound enzyme that catalyzes the hydrolysis of diacylglycerol to produce 2-AG[@stella1997]. The enzyme belongs to the serine hydrolase family and contains the characteristic catalytic triad (Ser-Asp-His) found in lipases. DAGL-β localizes primarily to postsynaptic neurons, where it synthesizes 2-AG in response to neuronal activity.

Key biochemical properties:

Substrate specificity: Prefers sn-1,2-diacylglycerols with arachidonoyl (20:4) fatty acid chains
Regional distribution: Highest activity in the cerebellum, hippocampus, and prefrontal cortex
Cellular localization: Enriched in postsynaptic dendritic spines
Regulation: Activity modulated by calcium influx and G-protein coupled receptor signaling

2-AG Biosynthesis Pathway

The 2-AG biosynthetic pathway involves multiple enzymatic steps:

Phospholipase A2 (PLA2): Converts membrane phospholipids to arachidonic acid

Diacylglycerol kinase (DGK): Phosphorylates DAG to phosphatidic acid (alternative pathway)

DAGL-β: Hydrolyzes DAG to produce 2-AG (primary pathway)

The produced 2-AG then acts as a retrograde messenger, traveling backward across the synapse to activate presynaptic [CB1 receptors](/proteins/cb1-receptor), modulating neurotransmitter release[@marsicano2003].

Role in Endocannabinoid Signaling

Retrograde Synaptic Transmission

DAGL-β is essential for activity-dependent retrograde signaling in the brain[@kano2009]. When postsynaptic neurons are depolarized, intracellular calcium levels rise, triggering DAGL-β to produce 2-AG. This 2-AG then diffuses backward to activate presynaptic CB1 receptors, which inhibit the release of excitatory (glutamate) or inhibitory (GABA) neurotransmitters.

This mechanism allows postsynaptic neurons to dynamically regulate their own input:

Depolarization-induced suppression of excitation (DSE): 2-AG reduces glutamate release
Depolarization-induced suppression of inhibition (DSI): 2-AG reduces GABA release
Short-term plasticity: Forms the basis of several forms of short-term synaptic plasticity

CB1 and CB2 Receptor Signaling

Once released, 2-AG activates both [CB1 receptors](/proteins/cb1-receptor) and [CB2 receptors](/proteins/cb2-receptor)[@hebert2009]:

CB1 receptors: Predominantly expressed in the central nervous system, particularly in presynaptic terminals. Activation inhibits voltage-gated calcium channels, reduces neurotransmitter release, and modulates ion channel activity.
CB2 receptors: Primarily expressed in immune cells including microglia. Activation modulates neuroinflammation and microglial activation states.

Role in Neurodegeneration

Alzheimer's Disease

Endocannabinoid signaling is profoundly altered in Alzheimer's disease (AD)[@fernandezrodriguez2022]. DAGL-β dysfunction may contribute to:

Synaptic plasticity deficits: Impaired retrograde signaling affects long-term potentiation (LTP) and memory formation
Neuroinflammation: 2-AG has immunomodulatory properties; dysregulation affects microglial activation and cytokine production
Excitotoxicity: Altered GABAergic signaling may contribute to neuronal hyperexcitability
Amyloid pathology: Endocannabinoid signaling interacts with amyloid precursor protein (APP) processing

Studies show decreased 2-AG levels in AD brains and altered CB1 receptor expression. This dysregulation may represent both a consequence of pathology and a potential therapeutic target.

Parkinson's Disease

In Parkinson's disease (PD), DAGLB genetic variants have been associated with disease risk[@keeer2019]. Endocannabinoid signaling is hyperactive in PD, particularly in the [basal ganglia](/brain-regions/basal-ganglia), contributing to:

Motor impairment: Elevated 2-AG and CB1 activation may exacerbate hypokinetic symptoms
Dopaminergic neuron vulnerability: Endocannabinoid dysregulation affects survival of dopaminergic neurons
Levodopa-induced dyskinesia: CB1 receptor overactivation is implicated in dyskinesia development

DAGL inhibitors have shown promise in preclinical PD models for reducing dyskinesia while maintaining therapeutic benefit.

Neuroinflammation

The DAGL-β/2-AG pathway plays a complex role in neuroinflammation[@blazquez2021]:

Pro-resolution signaling: 2-AG can promote anti-inflammatory microglial phenotypes
Cytokine modulation: 2-AG regulates the production of pro-inflammatory cytokines including TNF-α, IL-1β, and IL-6
Microglial activation: CB2 receptor-mediated 2-AG signaling modulates microglial migration and phagocytosis

Dysregulated 2-AG signaling may contribute to chronic neuroinflammation characteristic of neurodegenerative diseases.

Neuroprotection

Endocannabinoid signaling via 2-AG has demonstrated neuroprotective properties[@GarciaGutierrez2020]:

Oxidative stress reduction: 2-AG activation of CB2 receptors reduces ROS production
Excitotoxicity prevention: CB1 receptor activation inhibits glutamate release and associated excitotoxic damage
Autophagy modulation: 2-AG can enhance autophagic flux, promoting clearance of protein aggregates
Anti-apoptotic signaling: CB1 and CB2 activation activate pro-survival pathways including PI3K/Akt

Expression Patterns

Brain Expression

DAGLB is highly expressed in neurons throughout the brain:

Hippocampus: CA1-CA3 pyramidal neurons, dentate gyrus granule cells
Cortex: Layer V pyramidal neurons, interneurons
Cerebellum: Purkinje cells, granule cells
Basal ganglia: Medium spiny neurons in striatum, dopaminergic neurons in substantia nigra
Thalamus: Relay neurons

Cellular Localization

DAGL-β primarily localizes to:

Postsynaptic dendritic spines
Axon initial segments
Somatic and dendritic membranes
Axonal varicosities (presynaptic terminals in some brain regions)

Therapeutic Implications

DAGL Inhibitors

Small molecule DAGL inhibitors are under investigation for treating neurodegenerative diseases[@di2020]:

Tetrahydrolipstatin (THL): Pan-DAGL inhibitor with activity in vivo
DO34: Selective DAGL inhibitor with improved brain penetration
KT-109: DAGL inhibitor with anti-inflammatory properties

Potential therapeutic applications:

Neuroinflammation: Reducing pro-inflammatory cytokine production
Parkinson's disease: Modulating basal ganglia excitability
Addiction: Interrupting endocannabinoid-mediated reinforcement

DAGL Activators

Alternatively, DAGL activators could enhance 2-AG signaling:

Neuroprotection: Boosting endogenous neuroprotective signaling
Memory enhancement: Potentiating retrograde synaptic plasticity
Anti-depressive effects: Modulating emotional processing

Genetic Considerations

DAGLB mutations cause early-onset progressive cerebellar ataxia in humans[@presburger2019], demonstrating the critical role of this enzyme in motor control and cerebellar function. These findings suggest that modulating DAGL activity must be carefully balanced to avoid disrupting essential physiological functions.

Protein-Protein Interactions

Interacting Partners

DAGL-β interacts with multiple proteins that regulate its activity and localization:

CB1 Receptor: Physical association with CB1 receptors localizes DAGL-β to postsynaptic compartments
Homer Proteins: Homer1/2/3 scaffold DAGL-β at postsynaptic densities
mGluR5: Group I metabotropic glutamate receptors coordinate DAGL-β activation with synaptic activity
PLCβ: Phospholipase C β isoforms generate DAG substrate for DAGL-β
RGS Proteins: Regulators of G-protein signaling modulate DAGL-β through GAP activity

Signaling Complexes

DAGL-β forms multiprotein signaling complexes at synapses:

Retrograde signaling complex: mGluR1/5 → PLCβ → DAG → DAGL-β → 2-AG → CB1

Immunomodulatory complex: CB2 → Gi/o → DAGL-β → 2-AG → CB2 (microglia)

Metabolic complex: DAGL-β interacts with lipid metabolizing enzymes

Structural Biology

Catalytic Mechanism

DAGL-β employs a serine hydrolase catalytic mechanism:

Catalytic triad: Ser-Asp-His arrangement typical of lipases
Active site: Hydrophobic pocket accommodating DAG substrate
Regulation: Allosteric sites modulate activity in response to lipids
Post-translational modifications: Phosphorylation and lipidation affect localization

Isoforms

DAGL-β has multiple isoforms with distinct properties:

Full-length DAGL-β (672 aa): Primary isoform in brain
DAGL-α (672 aa): Alternative splice variant with different tissue distribution
Splice variants: Different N-terminal regions affect subcellular localization

Experimental Models

Animal Models

DAGL-β knockout and conditional knockout mice have been characterized:

Global KO: Severe reduction in brain 2-AG (>80%), impaired retrograde signaling
Neuron-specific KO: Disrupted DSE/DSI without motor deficits
Conditional KO: Allows spatial-temporal control of DAGL-β deletion
Knock-in: Reporter tags enable visualization of DAGL-β expression

Cell Models

In vitro systems used to study DAGL-β:

HEK293T cells: Heterologous expression for biochemical characterization
Primary neurons: Cultured neurons for synaptic studies
Microglial cultures: For neuroinflammation studies
iPSC-derived neurons: Human models for disease modeling

Disease Mechanisms

Molecular Pathways

DAGL-β dysfunction affects multiple molecular pathways:

cAMP/PKA pathway: CB1 receptor activation inhibits adenylate cyclase

MAPK pathway: Both CB1 and CB2 activate MAPK signaling

PI3K/Akt pathway: Anti-apoptotic signaling through Akt phosphorylation

mTOR pathway: 2-AG signaling affects mTORC1 activity

NF-κB pathway: CB2-mediated inflammation involves NF-κB

Cellular Effects

DAGL-β dysregulation leads to:

Synaptic dysfunction: Impaired retrograde signaling affects LTP/LTD
Neuronal death: Excitotoxicity and apoptosis through multiple pathways
Glial activation: Microglial and astrocytic responses to altered 2-AG
Metabolic disturbances: Lipid signaling affects mitochondrial function

Research Highlights

DAGL-β knockout mice show severely reduced 2-AG levels (>80% decrease) and impaired retrograde signaling
Conditional DAGL-β deletion in postsynaptic neurons disrupts DSI/DSI without affecting motor coordination
DAGL-β activity is modulated by synaptic activity and calcium-dependent phosphorylation
The enzyme shows differential sensitivity to pharmacological inhibition compared to DAGL-α
Single nucleotide polymorphisms (SNPs) in DAGLB have been associated with Parkinson's disease risk in genome-wide association studies (GWAS)

Summary

DAGLB encodes diacylglycerol lipase beta, the key enzyme responsible for synthesizing 2-AG, the predominant endocannabinoid in the brain. This enzyme is essential for activity-dependent retrograde synaptic signaling, modulating neurotransmitter release throughout the central nervous system. DAGL-β dysfunction has been implicated in Alzheimer's disease, Parkinson's disease, and cerebellar ataxias, making it a potential therapeutic target. The enzyme's role in neuroinflammation and neuroprotection provides multiple angles for intervention. Further research into DAGL-β modulation may yield treatments for neurodegenerative diseases while avoiding the adverse effects associated with direct cannabinoid receptor agonists.

DAGLB

DAGLB

Overview

DAGLB

Overview

Gene Information

Molecular Function

Enzymatic Activity

2-AG Biosynthesis Pathway

Role in Endocannabinoid Signaling

Retrograde Synaptic Transmission

CB1 and CB2 Receptor Signaling

Role in Neurodegeneration

Alzheimer's Disease

Parkinson's Disease

Neuroinflammation

Neuroprotection

Expression Patterns

Brain Expression

Cellular Localization

Therapeutic Implications

DAGL Inhibitors

DAGL Activators

Genetic Considerations

Protein-Protein Interactions

Interacting Partners

Signaling Complexes

Structural Biology

Catalytic Mechanism

Isoforms

Experimental Models

Animal Models

Cell Models

Disease Mechanisms

Molecular Pathways

Cellular Effects

Research Highlights

Summary

See Also