SIRT5 Protein - Mitochondrial Desuccinylase

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SIRT5 Protein - Mitochondrial Desuccinylase

Introduction

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">SIRT5 Protein - Mitochondrial Desuccinylase</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>SIRT5</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>6p23</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>25998</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>Q9NXE1</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000124562</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~34 kDa (full-length)</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>310 amino acids</td>
</tr>
<tr>
<td class="label">Substrate</td>
<td>Function</td>
</tr>
<tr>
<td class="label">GLUD1</td>
<td>Glutamate dehydrogenase</td>
</tr>
<tr>
<td class="label">HMGCS2</td>
<td>Mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase 2</td>
</tr>
<tr>
<td class="label">CPS1</td>
<td>Carbamoyl phosphate synthetase 1</td>
</tr>
<tr>
<td class="label">SDH</td>
<td>Succinate dehydrogenase</td>
</tr>
<tr>
<td class="label">IDH2</td>
<td>Isocitrate dehydrogenase 2</td>
</tr>
<tr>
<td class="label">OGDH</td>
<td>α-ketoglutarate dehydrogenase</td>
</tr>
<tr>
<td class="label">PKM2</td>
<td>Pyruvate kinase M2</td>
</tr>
<tr>
<td class="label">GAPDH</td>
<td>Glyceralde

...

SIRT5 Protein - Mitochondrial Desuccinylase

Introduction

Sirt5 Protein Mitochondrial Desuccinylase is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Overview

SIRT5 (Sirtuin 5) is a mitochondrial nicotinamide adenine dinucleotide (NAD+)-dependent protein deacylase that localizes to the mitochondrial matrix. Unlike other sirtuins that primarily function as deacetylases, SIRT5 exhibits unique enzymatic activities including desuccinylation, demalonylation, and deglutarylation, making it a critical regulator of mitochondrial protein post-translational modifications. SIRT5 plays essential roles in maintaining mitochondrial metabolic homeostasis, regulating energy production, and protecting against oxidative stress in [neurons](/entities/neurons) and other cell types. Recent research has implicated SIRT5 dysfunction in multiple neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and Huntington's disease, making it an attractive therapeutic target. [@sirta]

Gene and Protein Structure

Gene Information

The SIRT5 gene is located on chromosome 6p23 and encodes a member of the sirtuin family of NAD+-dependent deacetylases. SIRT5 is one of seven mammalian sirtuins (SIRT1-7), with SIRT3, SIRT4, and SIRT5 being primarily mitochondrial in localization. [@sirtb]

Protein Domain Architecture

SIRT5 possesses the characteristic sirtuin fold with several unique features:

N-terminal mitochondrial targeting sequence (MTS): First ~50 amino acids form an amphipathic helix that directs import into mitochondria via the TOM/TIM translocase system
Rossmann-fold catalytic core: The central domain (~200 amino acids) adopts the characteristic sirtuin fold with a Rossmann-fold structure for NAD+ binding
NAD+-binding pocket: Highly conserved sequence motif involved in NAD+ binding and catalysis
Substrate-binding cavity: A unique cavity adjacent to the catalytic site accommodates the bulkier succinyl, malonyl, and glutaryl groups
C-terminal region: Contributes to substrate specificity

The three-dimensional structure reveals a conserved catalytic core surrounded by variable loops that determine substrate specificity, with the unique substrate-binding cavity explaining SIRT5's distinctive activity profile.

Normal Function

Enzymatic Activities

SIRT5 exhibits multiple NAD+-dependent enzymatic activities:

Desuccinylase activity (primary): Removes succinyl groups (-CO-CH2-CH2-COO-) from lysine residues

This is SIRT5's most robust activity
Regulates mitochondrial metabolic enzymes
Important for urea cycle and fatty acid oxidation

Demalonylase activity: Removes malonyl groups (-CO-CH2-COO-)

Similar mechanism to desuccinylation
Regulates metabolic enzymes

Deglutarylase activity: Removes glutaryl groups (-CO-(CH2)3-COO-)

Identified more recently
Regulates glutamate metabolism

Deacetylase activity: Traditional sirtuin activity

Weaker than other activities
Still functionally relevant

Key Mitochondrial Substrates

SIRT5 regulates numerous mitochondrial proteins through desuccinylation:

Metabolic Regulation

SIRT5 is a central regulator of mitochondrial metabolism:

Urea cycle: Desuccinylates CPS1, enhancing ammonia detoxification
Ketogenesis: Regulates HMGCS2 for ketone body production
TCA cycle: Modulates multiple enzymes including SDH and OGDH
Fatty acid oxidation: Regulates enzymes involved in β-oxidation
Gluconeogenesis: Affects metabolic pathways in liver

Reactive Oxygen Species (ROS) Management

IDH2 regulation: Desuccinylation enhances antioxidant function
Glutathione metabolism: Indirect effects on oxidative stress response
Mitochondrial redox balance: Overall protective effects

Role in Neurodegeneration

Alzheimer's Disease

SIRT5 is prominently involved in Alzheimer's disease pathogenesis:

Mitochondrial dysfunction:

Altered SIRT5 expression in AD brain
Succinylome dysregulation affects neuronal energy metabolism
Impaired mitochondrial respiration in AD models

Metabolic implications:

GLUD1 desuccinylation affects glutamate metabolism
Altered TCA cycle function contributes to hypometabolism
Ketone body production may be impaired

Therapeutic potential:

SIRT5 activators being explored for cognitive enhancement
Modulating succinylome as therapeutic strategy
Mitochondrial metabolic restoration

Parkinson's Disease

In Parkinson's disease, SIRT5 provides neuroprotection:

Dopaminergic neuron protection:

SIRT5 protects against MPTP toxicity
Maintains mitochondrial function in substantia nigra
Against 6-OHDA-induced cell death

Mechanisms:

Regulation of mitochondrial metabolic enzymes
Antioxidant defense enhancement
Preservation of complex I activity

[α-Synuclein](/proteins/alpha-synuclein) connections:

Succinylome alterations may affect protein aggregation
Mitochondrial dysfunction in PD linked to SIRT5

Huntington's Disease

SIRT5 dysfunction contributes to HD pathogenesis:

Metabolic defects:

Altered mitochondrial metabolism
Impaired energy production
Elevated succinylated proteins

Therapeutic implications:

SIRT5 modulation may improve mitochondrial function
Potential for therapeutic intervention

Amyotrophic Lateral Sclerosis

Altered SIRT5 in motor neuron disease
Mitochondrial dysfunction in ALS
Energy metabolism impairment

Multiple Sclerosis

Demyelination and mitochondrial dysfunction
SIRT5 role in oligodendrocyte survival
Energy metabolism in demyelinating disease

Therapeutic Targeting

SIRT5 Modulators

Activators under investigation:

NAD+ boosters increase SIRT5 activity
Small molecule SIRT5 activators in development

Inhibitors:

Used in research to probe SIRT5 function
Not yet clinically approved

Clinical Implications

Metabolic disorders: Diabetes, obesity
Neurodegeneration: AD, PD, HD
Cardiovascular disease: Cardiac metabolism
Cancer: Metabolic reprogramming

Interaction Network

SIRT5 interacts with multiple mitochondrial proteins and pathways:

NAD+: Essential cofactor for enzymatic activity
SIRT3: Related mitochondrial sirtuin with overlapping substrates
SIRT4: Related mitochondrial sirtuin
GLUD1: Glutamate dehydrogenase substrate
HMGCS2: Ketogenesis enzyme
CPS1: Urea cycle enzyme
IDH2: Mitochondrial NADP+-dependent isocitrate dehydrogenase
SDH: Succinate dehydrogenase
TOMM/TIM: Mitochondrial import machinery

Animal Models

Sirt5 knockout mice: Viable with metabolic phenotypes
Conditional knockouts: Tissue-specific deletion studies
Transgenic models: Overexpression studies
Disease models: Alzheimer's, Parkinson's models

Research Methods

Biochemistry: Enzyme assays, substrate identification
Proteomics: Succinylome, malonylome analysis
Metabolomics: Metabolic pathway profiling
Cell biology: Cell survival, [ROS](/entities/reactive-oxygen-species) measurement
Animal models: Behavioral and pathological analysis

Background

The study of Sirt5 Protein Mitochondrial Desuccinylase 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

References

[Unknown, - SIRT5 regulates the mitochondrial succinylome and metabolic functions (n.d.)](https://pubmed.ncbi.nlm.nih.gov/22100468/)

[Unknown, - SIRT5 demalonylase and desuccinylase activities (n.d.)](https://pubmed.ncbi.nlm.nih.gov/21499265/)

[Unknown, - SIRT5 deglutarylates glutamate dehydrogenase (n.d.)](https://pubmed.ncbi.nlm.nih.gov/23595488/)

[Unknown, - SIRT5 in cancer metabolism (n.d.)](https://pubmed.ncbi.nlm.nih.gov/25849368/)

[Unknown, - Mitochondrial sirtuins in neurodegeneration (n.d.)](https://pubmed.ncbi.nlm.nih.gov/26225660/)

[Unknown, - SIRT5 and mitochondrial function in aging (n.d.)](https://pubmed.ncbi.nlm.nih.gov/27105057/)

[Unknown, - Succinylome in Alzheimer's disease (n.d.)](https://pubmed.ncbi.nlm.nih.gov/28168276/)

[Unknown, - SIRT5 in Parkinson's disease (n.d.)](https://pubmed.ncbi.nlm.nih.gov/29801018/)

[Unknown, - SIRT5 deglutarylation activity (n.d.)](https://pubmed.ncbi.nlm.nih.gov/30605881/)

[Unknown, - SIRT5 as therapeutic target (n.d.)](https://pubmed.ncbi.nlm.nih.gov/31704182/)

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SIRT5 Protein - Mitochondrial Desuccinylase

SIRT5 Protein - Mitochondrial Desuccinylase

Introduction

SIRT5 Protein - Mitochondrial Desuccinylase

Introduction

Overview

Gene and Protein Structure

Gene Information

Protein Domain Architecture

Normal Function

Enzymatic Activities

Key Mitochondrial Substrates

Metabolic Regulation

Reactive Oxygen Species (ROS) Management

Role in Neurodegeneration

Alzheimer's Disease

Parkinson's Disease

Huntington's Disease

Amyotrophic Lateral Sclerosis

Multiple Sclerosis

Therapeutic Targeting

SIRT5 Modulators

Clinical Implications

Interaction Network

Animal Models

Research Methods

Background

External Links

See Also

References