GBA3 — Glucosidase Beta 3

GBA3 — Glucosidase Beta 3

Overview

GBA3 — Glucosidase Beta 3

Overview

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">GBA3 — Glucosidase Beta 3</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>GBA3</td>
</tr>
<tr>
<td class="label">Official Full Name</td>
<td>Glucosidase beta 3</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>4p15.2</td>
</tr>
<tr>
<td class="label">Gene ID</td>
<td>57733</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>Q9Y5K2</td>
</tr>
<tr>
<td class="label">Protein Class</td>
<td>Glycoside hydrolase, family 1</td>
</tr>
<tr>
<td class="label">Approach</td>
<td>Target</td>
</tr>
<tr>
<td class="label">Enzyme replacement</td>
<td>GBA3 activity</td>
</tr>
<tr>
<td class="label">Small molecule activators</td>
<td>Increase activity</td>
</tr>
<tr>
<td class="label">Gene therapy</td>
<td>Restore expression</td>
</tr>
<tr>
<td class="label">Substrate reduction</td>
<td>Reduce substrate burden</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/hypertension" style="color:#ef9a9a">Hypertension</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">9 edges</a></td>
</tr>
</table>

GBA3 is a human gene. This page covers the gene's normal function, disease associations, expression patterns, and key research findings relevant to neurodegeneration.

The GBA3 gene encodes a member of the glycoside hydrolase family, specifically a lysosomal glucocerebrosidase enzyme. Also known as beta-glucosidase or glucosidase beta 3, this enzyme catalyzes the hydrolysis of glycolipids and is genetically distinct from the well-known [GBA](/genes/gba) gene (glucosylceramidase). GBA3 has been implicated in Parkinson's disease risk and participates in cellular lipid metabolism.

Gene Overview

Nomenclature

• Official Name: Glucosidase beta 3
• Alternate Names: β-glucosidase, glucosylceramidase 2, CBGL1
• HGNC ID: 24523

Protein Structure

GBA3 encodes a 556-amino acid protein with:

The enzyme is a homodimer in its active form, requiring optimal pH 4.5-5.5 for activity.

Enzymatic Function

Catalytic Activity

GBA3 hydrolyzes:

• Glucosylceramide → Glucose + Ceramide
• Glucosylsphingosine (lyso-GL1) → Glucose + Sphingosine
• Other glycolipids: Various β-glucosidic bonds

Substrate Specificity

Unlike GBA (acid β-glucosidase), GBA3 shows:

• Broader substrate specificity
• Activity toward glucosylceramide and glucosylsphingosine
• Lower catalytic efficiency toward glucosylceramide
• Potential activity toward isoflavone glucosides (genistein, daidzein)

Expression Pattern

GBA3 is expressed in:

• Liver: Hepatocytes (highest expression)
• Kidney: Renal tubules
• Small Intestine: Enterocytes
• Brain: Lower expression, various regions
• Immune Cells: Monocytes, macrophages
• Placenta: Trophoblastic cells

Biological Roles

Glycolipid Metabolism

GBA3 participates in glycosphingolipid catabolism:

• Sphingolipid Turnover: Breakdown of glucosylceramide for recycling
• Ceramide Generation: Provides ceramide for signaling molecules
• Membrane Composition: Maintains proper lipid bilayer composition
• Cell Homeostasis: Prevents accumulation of glycosphingolipids

Isoflavone Metabolism

Unique to GBA3, the enzyme can hydrolyze:

• Genistein glucoside (daidzein)
• Daidzin
• Glycitin

Potential Neuroprotective Functions

In the brain, GBA3 may:

• Process glucosylceramide in neurons
• Generate ceramide for pro-survival signaling
• Interact with α-synuclein clearance pathways

Clinical Significance

Parkinson's Disease

The GBA gene is a well-established PD risk factor. GBA3 has also been studied:

Research is ongoing to determine if GBA3 variants:

• Increase susceptibility to α-synuclein pathology
• Modify disease severity
• Influence treatment response

Gaucher Disease

While GBA (not GBA3) is the primary gene causing Gaucher disease, GBA3 variants:

• May modify disease severity in GBA carriers
• Could provide compensation for GBA deficiency
• Are being studied for therapeutic potential

Other Associations

• Type 2 Diabetes: Some studies link GBA3 variants to glucose metabolism
• Liver Disease: Potential role in glycolipid metabolism in hepatocytes
• Isoflavone Response: May influence response to soy-based therapies

Interaction Network

GBA3 interacts with:

Lipid Metabolism Proteins

• GBA (glucosylceramidase) - Paralogs
• GBA2 (non-lysosomal glucosylceramidase)
• ASM (acid sphingomyelinase)
• GALC (galactocerebrosidase)

Lysosomal Proteins

• LAMP1, LAMP2 (lysosomal membrane proteins)
• CTSB, CTSD (cathepsins)
• GLA (α-galactosidase A)

Signaling Molecules

• Ceramide and its metabolites
• Sphingosine-1-phosphate
• Glucosylceramide

Genetic Variants

Known Polymorphisms

Several SNPs in GBA3 have been studied:

• rs2010963: In 5'UTR, affects expression
• rs4556890: In coding region
• rs1054892: Missense variant

Functional Variants

• rs2234246: Associated with enzyme activity
• rs3743548: In regulatory region
• Various rare variants with unknown function

Population Genetics

• Different allele frequencies across populations
• Positive selection in some East Asian populations (possibly due to isoflavone metabolism)

Research Tools

Model Systems

• Knockout mice: Gba3 knockout mice are viable
• Zebrafish models: For developmental studies
• In vitro expression: HEK293, COS cells
• Yeast models: For enzymatic studies

Biochemical Tools

• Substrates: Fluorescent glucosylceramide analogs
• Inhibitors: Specific inhibitors being developed
• Antibodies: For protein detection
• Recombinant proteins: For structural studies

Therapeutic Potential

Implications for Parkinson's Disease

Understanding GBA3 may help:

• Explain variability in GBA-associated PD
• Develop targeted therapies
• Identify biomarkers for risk stratification

Summary

GBA3 encodes a lysosomal β-glucosidase with roles in glycolipid metabolism and potential implications for Parkinson's disease. While less studied than its paralog GBA, this enzyme contributes to:

• Glucosylceramide and glucosylsphingosine catabolism
• Isoflavone metabolism (unique function)
• Cellular lipid homeostasis

See Also

• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)

External Links

• [NCBI Gene: GBA3](https://www.ncbi.nlm.nih.gov/gene/?term=GBA3)
• [GeneCards: GBA3](https://www.genecards.org/cgi-bin/carddisp.pl?gene=GBA3)
• [OMIM: GBA3](https://omim.org/search?search=GBA3)
• [Ensembl: GBA3](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=GBA3)
• [Allen Brain Atlas: GBA3](https://human.brain-map.org/microarray/search/show?search_term=GBA3)

References

Pathway Diagram

The following diagram shows the key molecular relationships involving GBA3 — Glucosidase Beta 3 discovered through SciDEX knowledge graph analysis: