LRPPRC — Leucine-Rich Pentatricopeptide Repeat Containing

LRPPRC — Leucine-Rich Pentatricopeptide Repeat Containing

Introduction

LRPPRC — Leucine-Rich Pentatricopeptide Repeat Containing

Introduction

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">LRPPRC — Leucine-Rich Pentatricopeptide Repeat Containing</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>LRPPRC</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Leucine-Rich Pentatricopeptide Repeat Containing</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>2p21</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>90333</td>
</tr>
<tr>
<td class="label">OMIM</td>
<td>607544</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000138095</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>Q9GZL0</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>1,394 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~156 kDa</td>
</tr>
<tr>
<td class="label">Expression</td>
<td>High in tissues with high mitochondrial content: brain, heart, skeletal muscle, kidney</td>
</tr>
<tr>
<td class="label">Complex</td>
<td>Subunits Affected</td>
</tr>
<tr>
<td class="label">Complex I</td>
<td>Multiple NADH dehydrogenase subunits</td>
</tr>
<tr>
<td class="label">Complex III</td>
<td>Some cytochrome b subunits</td>
</tr>
<tr>
<td class="label">Complex IV</td>
<td>Some COX subunits</td>
</tr>
<tr>
<td class="label">Complex V</td>
<td>Minimal effect</td>
</tr>
<tr>
<td class="label">Feature</td>
<td>Details</td>
</tr>
<tr>
<td class="label">Inheritance</td>
<td>Autosomal recessive</td>
</tr>
<tr>
<td class="label">Prevalence</td>
<td>1 in 40,000 (Quebec, Canada)</td>
</tr>
<tr>
<td class="label">Ethnicity</td>
<td>Founder effect in French-Canadian population</td>
</tr>
<tr>
<td class="label">Onset</td>
<td>Infancy to early childhood</td>
</tr>
<tr>
<td class="label">Features</td>
<td>Developmental regression, lactic acidosis, neurodegeneration</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/colorectal-cancer" style="color:#ef9a9a">Colorectal Cancer</a>, <a href="/wiki/liver-cancer" style="color:#ef9a9a">Liver Cancer</a>, <a href="/wiki/parkinson" style="color:#ef9a9a">Parkinson</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">48 edges</a></td>
</tr>
</table>

LRPPRC (Leucine-Rich Pentatricopeptide Repeat Containing) is a mitochondrial RNA-binding protein that plays crucial roles in mitochondrial gene expression, mRNA stability, and translation. Originally identified through genetic studies of Leigh syndrome French-Canadian type (LSFC), LRPPRC has emerged as a critical regulator of mitochondrial function with implications for neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and related disorders [@morin2004][@ruzzenente2012].

The protein contains multiple pentatricopeptide (PPR) repeat domains that form RNA-binding scaffolds, allowing it to interact with specific mitochondrial mRNAs and regulate their processing, stability, and translation. Loss of LRPPRC function leads to impaired mitochondrial respiratory chain assembly, particularly affecting Complex I (NADH dehydrogenase), and contributes to neuronal death through energy deficiency and oxidative stress [@cuo2013][@yang2018].

Gene Information

Normal Function

LRPPRC encodes a leucine-rich pentatricopeptide repeat (PPR) protein that localizes to mitochondria and is involved in post-transcriptional regulation of mitochondrial gene expression. The protein binds to mitochondrial mRNAs and regulates their stability, processing, and translation. It plays a crucial role in maintaining proper levels of respiratory chain components [@ruzzenente2012][@cuo2013].

Structural Features

LRPPRC contains several distinctive structural elements:

The modular structure allows LRPPRC to act as a molecular adaptor, bringing together different components of the mitochondrial translation machinery and coordinating RNA processing events.

Molecular Functions

Mitochondrial mRNA Stability

LRPPRC binds to mitochondrial mRNAs and protects them from degradation:

• mRNA protection: Binds to the 3' untranslated regions of specific mRNAs
• Stability regulation: Prevents rapid decay of mitochondrial transcripts
• Processing coordination: Facilitates proper RNA processing and maturation

Translation Regulation

LRPPRC coordinates mitochondrial translation:

• Ribosome interaction: Associates with mitochondrial ribosomes
• Translation initiation: May facilitate translation initiation for specific mRNAs
• Elongation coordination: Modulates the translation elongation process

RNA Processing

The protein is involved in mitochondrial RNA processing:

• 3'-end processing: Facilitates proper 3' end formation of mitochondrial transcripts
• Polyadenylation: Interacts with the mitochondrial poly(A) tail
• RNA maturation: Coordinates the transition from precursor to mature mRNA

Mitochondrial Gene Expression

LRPPRC is essential for the expression of mitochondrial-encoded genes, particularly those encoding Complex I (NADH dehydrogenase) subunits. Loss of LRPPRC function leads to:

• Reduced stability of mitochondrial mRNAs
• Impaired synthesis of mitochondrial proteins
• Defective assembly of the respiratory chain
• Cellular energy deficiency

Complex I Specificity

LRPPRC deficiency particularly affects Complex I:

This specificity reflects the preferential binding of LRPPRC to Complex I subunit mRNAs.

Disease Associations

Leigh Syndrome French-Canadian Type (LSFC)

LRPPRC mutations cause LSFC, a severe mitochondrial disorder:

Pathogenic variants: A354V, V368I, R433C, P789L and others

Mechanism: Impaired mitochondrial mRNA processing leads to Complex I deficiency, causing energy failure especially in brain regions with high energy demands.

Mitochondrial DNA Depletion Syndrome

• Null alleles cause severe depletion
• Reduced mtDNA maintenance
• Multiple organ involvement

Neurodegeneration

LRPPRC dysfunction contributes to:

• Alzheimer's disease: Altered mitochondrial function in AD brains
• Parkinson's disease: Energy deficits in dopaminergic neurons
• Other disorders: Various neurodegenerative conditions

Cancer Metabolism

• Altered LRPPRC expression in cancer cells
• Affects mitochondrial function in tumors
• Influences tumor metabolism and growth

Cardiomyopathy

• Mitochondrial dysfunction due to LRPPRC deficiency
• Affects cardiac muscle function
• Energy deficiency in heart tissue

Expression Pattern

LRPPRC is broadly expressed with highest levels in tissues with high mitochondrial content:

• Brain: High expression in neurons, particularly vulnerable populations
• Heart: Cardiac muscle requires continuous energy production
• Skeletal muscle: High energy demands during activity
• Kidney: Metabolic activity in renal tubular cells

• Energy demand
• Mitochondrial biogenesis signals
• Cellular stress conditions

Molecular Mechanisms

Energy Failure

LRPPRC deficiency leads to ATP production failure:

• Complex I dysfunction reduces NADH oxidation
• Impaired oxidative phosphorylation
• Reduced ATP/ADP ratio
• Cellular energy crisis

Oxidative Stress

Mitochondrial dysfunction causes ROS accumulation:

• Electron leak from damaged complexes
• Lipid peroxidation
• Protein oxidation
• DNA damage

Neuronal Vulnerability

Neurons are particularly sensitive:

• High energy requirements
• Limited regenerative capacity
• Complex morphology requiring efficient transport
• Post-mitotic nature cannot dilute damage

Therapeutic Approaches

Small Molecule Therapies

• Mitochondrial CoQ10: Support electron transport
• L-carnitine: Improve fatty acid oxidation
• Riboflavin: Support Complex I function
• Alpha-lipoic acid: Antioxidant support

Gene Therapy

• AAV-mediated LRPPRC delivery: Restore function
• Gene replacement strategies: Compensate for loss
• mRNA therapeutics: Deliver functional transcripts

Supportive Care

• Metabolic supplements: Support energy metabolism
• Seizure control: Anticonvulsant therapy
• Physical therapy: Maintain function
• Nutritional support: Dietary management

Cross-Links

• [Mitochondrial Dysfunction](/mechanisms/mitochondrial-dysfunction) — Core mechanism
• [Leigh Syndrome](/diseases/leigh-syndrome) — Associated disease
• [Mitochondrial DNA Depletion](/mechanisms/mitochondrial-dna-depletion) — Related mechanism
• [Oxidative Stress](/mechanisms/oxidative-stress-neurodegeneration) — Downstream effect
• [Complex I Deficiency](/mechanisms/complex-i-deficiency) — Biochemical consequence

Key Publications

See Also

• [Mitochondrial Gene Expression](/mechanisms/mitochondrial-gene-expression)
• [Leigh Syndrome](/diseases/leigh-syndrome)
• [Complex I Deficiency](/mechanisms/complex-i-deficiency)
• [Mitochondrial Translation](/mechanisms/mitochondrial-translation)
• [Energy Metabolism](/mechanisms/energy-metabolism)

References

Pathway Diagram

The following diagram shows the key molecular relationships involving LRPPRC — Leucine-Rich Pentatricopeptide Repeat Containing discovered through SciDEX knowledge graph analysis: