HMGCR Protein — HMG-CoA Reductase

HMGCR Protein — HMG-CoA Reductase

Overview

Pathway Diagram

```mermaid
flowchart TD
HMGCR["HMGCR<br/>HMG-CoA Reductase<br/>Rate-limiting enzyme"]

Cholesterol["Cholesterol<br/>Biosynthesis<br/>Pathway"]
Statins["Statin Therapy<br/>HMGCR Inhibition"]

APP["APP<br/>Amyloid Precursor<br/>Protein"]
PSEN1["PSEN1<br/>Presenilin-1<br/>gamma-secretase component"]
MAPT["MAPT<br/>Tau Protein<br/>Microtubule binding"]

Inflammation["Neuroinflammation<br/>IL1B-mediated<br/>responses"]
IL1B["IL1B<br/>Interleukin-1beta<br/>Pro-inflammatory"]

Apoptosis["Apoptosis<br/>Pathway<br/>Cell death"]
PARP1["PARP1<br/>DNA repair<br/>enzyme"]
DAPK1["DAPK1<br/>Death-associated<br/>protein kinase"]

Alzheimer["Alzheimer's<br/>Disease"]
ALS["ALS<br/>Motor neuron<br/>degeneration"]
Dementia["Dementia<br/>Cognitive decline"]
Depression["Depression<br/>Mood disorder"]

HMGCR -->|"regulates"| Cholesterol
HMGCR -->|"interacts_with"| APP
HMGCR -->|"interacts_with"| PSEN1
HMGCR -->|"interacts_with"| MAPT
HMGCR -->|"inhibits"| Inflammation
HMGCR -->|"interacts_with"| IL1B
HMGCR -->|"modulates"| Apoptosis
HMGCR -->|"interacts_with"| PARP1
HMGCR -->|"interacts_with"| DAPK1

Statins -->|"inhibits"| HMGCR

APP -->|"contributes_to"| Alzheimer
PSEN1 -->|"contributes_to"| Alzheimer
MAPT -->|"contributes_to"| Alzheimer

HMGCR -->|"associated_with"| Alzheimer
HMGCR -->|"associated_with"| ALS
HMGCR -->|"therapeutic_target"| Dementia
HMGCR -->|"asso

HMGCR Protein — HMG-CoA Reductase

Overview

Pathway Diagram

Hmgcr Protein — Hmg Coa Reductase plays an important role in the study of neurodegenerative diseases. This page provides comprehensive information about this topic, including its mechanisms, significance in disease processes, and therapeutic implications.

Introduction

Hmgcr Protein — Hmg Coa Reductase is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes. [@carter2007]

HMG-CoA reductase (HMGCR) is the rate-limiting enzyme in the mevalonate pathway for cholesterol biosynthesis. It catalyzes the conversion of HMG-CoA to mevalonate. While extensively studied for its role in cardiovascular disease and as the target of statins, HMGCR also plays important roles in [brain cholesterol metabolism](/entities/brain-cholesterol-metabolism). In [neurons](/entities/neurons), cholesterol is essential for synaptic vesicle formation, neurotransmitter release, and membrane rafts that host signaling proteins.

Protein Overview

<div class="infobox infobox-protein">
<table>
<tr><th colspan="2" style="background:#f0f0f0;">HMGCR</th></tr>
<tr><td><b>Protein Name</b></td><td>HMG-CoA Reductase</td></tr>
<tr><td><b>Gene</b></td><td>[HMGCR](/genes/hmgcr)</td></tr>
<tr><td><b>UniProt ID</b></td><td>[P04035](https://www.uniprot.org/uniprotkb/P04035/entry)</td></tr>
<tr><td><b>PDB IDs</b></td><td>1HMG, 2RBC</td></tr>
<tr><td><b>Molecular Weight</b></td><td>97 kDa</td></tr>
<tr><td><b>Subcellular Location</b></td><td>Endoplasmic Reticulum membrane</td></tr>
<tr><td><b>Protein Family</b></td><td>HMG-CoA reductase family</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/ad" style="color:#ef9a9a">AD</a>, <a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">ALZHEIMER</a>, <a href="/wiki/alzheimer's-disease" style="color:#ef9a9a">ALZHEIMER'S DISEASE</a>, <a href="/wiki/ami" style="color:#ef9a9a">AMI</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">315 edges</a></td>
</tr>
</table>
</div>

Structure

CYP46A1 Structure

• Contains the conserved P450 heme-binding domain
• N-terminal transmembrane anchor for ER localization
• Substrate access channel for cholesterol

HMGCR Structure

• N-terminal transmembrane domain (8 transmembrane helices)
• C-terminal catalytic domain facing the cytosol
• Sterol-sensing domain for regulation

SREBF2 Structure

• N-terminal transcription activation domain
• Basic-helix-loop-helix (bHLH) DNA-binding domain
• Two transmembrane helices anchor to ER
• Sterol-sensing domain

Normal Function

Cholesterol Metabolism

HMGCR is central to maintaining cholesterol homeostasis:

CYP46A1:

• Converts cholesterol to 24(S)-hydroxycholesterol
• Enables cholesterol efflux across [BBB](/entities/blood-brain-barrier)
• Regulated by LXR nuclear receptors

• Rate-limiting step in cholesterol synthesis
• Feedback inhibition by cholesterol
• Target of statin medications

• Master regulator of cholesterol genes
• Activates LDLR, HMGCR, and other genes
• Regulated by cellular cholesterol levels

Role in Alzheimer's Disease

Cholesterol-Aβ Relationship

Elevated brain cholesterol is associated with increased [Aβ](/proteins/amyloid-beta) production:

• Cholesterol-rich lipid rafts host [APP](/entities/app-protein) processing enzymes
• Altered membrane fluidity affects secretase activity
• Cholesterol depletion reduces Aβ generation

Therapeutic Implications

| Target | Approach | Status |
|--------|----------|--------|
| CYP46A1 | Activation | Preclinical |
| HMGCR | Statins | Clinical trials |
| SREBP-2 | Modulation | Research |

See Also

• [Proteins/Hmgcr-Protein](/proteins/hmgcr-protein) — This page

Overview

Hmgcr Protein — Hmg Coa Reductase plays an important role in the study of neurodegenerative diseases. This page provides comprehensive information about this topic, including its mechanisms, significance in disease processes, and therapeutic implications.

Background

The study of Hmgcr Protein — Hmg Coa Reductase has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.

External Links

• [PubMed](https://pubmed.ncbi.nlm.nih.gov/) - Biomedical literature
• [Alzheimer's Disease Neuroimaging Initiative](https://adni.loni.usc.edu/) - Research data
• [Allen Brain Atlas](https://brain-map.org/) - Brain gene expression data

Cross-References

• CYP46A1 Gene - Encoding gene
• HMGCR Gene - Encoding gene
• SREBF2 Gene - Encoding gene
• Cholesterol Metabolism in AD
• APOE Gene - Apolipoprotein E

References