DNAJA3 Protein

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DNAJA3 (Tid1) - DnaJ Heat Shock Protein Family Member A3

Introduction

Dnaja3 Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

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DNAJA3 (Tid1) - DnaJ Heat Shock Protein Family Member A3

Introduction

Dnaja3 Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

<table class="infobox infobox-protein"> [@zhang2019]
<tr> [@chen2010]
<th class="infobox-header" colspan="2">DNAJA3 (Tid1)</th> [@mccoy2021]
</tr> [@burbulla2022]
<tr> [@youle2012]
<td class="infobox-header" colspan="2">Mitochondrial Co-Chaperone</td> [@pickrell2015]
</tr> [@lin2006]
<tr>
<td class="label">Gene Symbol</td>
<td>DNAJA3</td>
</tr>
<tr>
<td class="label">Protein Name</td>
<td>DnaJ Heat Shock Protein Family Member A3</td>
</tr>
<tr>
<td class="label">Alternative Names</td>
<td>Tid1, TID1, mitochondrial DnaJ protein</td>
</tr>
<tr>
<td class="label">Gene</td>
<td>[DNAJA3](/genes/dnaja3)</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td><a href="https://www.uniprot.org/uniprot/Q96HS5" target="_blank">Q96HS5</a></td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>48 kDa</td>
</tr>
<tr>
<td class="label">Subcellular Localization</td>
<td>Mitochondria (inner membrane space and matrix)</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>Hsp40/DnaJ family (subfamily A)</td>
</tr>
<tr>
<td class="label">Tissue Expression</td>
<td>Ubiquitous; highest in heart, brain, skeletal muscle</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/infection" style="color:#ef9a9a">Infection</a>, <a href="/wiki/lymphoma" style="color:#ef9a9a">Lymphoma</a>, <a href="/wiki/tumor" style="color:#ef9a9a">Tumor</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">19 edges</a></td>
</tr>
</table>

Overview

DNAJA3 (also known as Tid1 for "tumorous imaginal disc 1") is a mitochondrial co-chaperone protein that plays critical roles in protein quality control, mitochondrial dynamics, and cell survival regulation. As a member of the Hsp40/DnaJ family, DNAJA3 functions as a co-chaperone for mitochondrial Hsp70 (mtHsp70/Grp75/mortalin), facilitating protein folding, import, and refolding within the mitochondrial matrix. The protein is encoded by the nuclear DNA and imported into mitochondria via the TOM/TIM translocase machinery.

DNAJA3 has emerged as an important player in neurodegenerative diseases due to its intimate involvement in mitochondrial quality control pathways, particularly mitophagy. It interacts with key proteins in the PINK1/Parkin mitophagy pathway and contributes to the selective elimination of damaged mitochondria—a process that is critically impaired in Parkinson's disease.

Molecular Structure and Function

Domain Architecture

DNAJA3 contains several functional domains:

N-terminal J Domain (residues 1-70): The conserved J domain that interacts with Hsp70 ATPase

Glycine/Phenylalanine-rich Region (residues 71-140): Flexible linker with chaperone activity

C-terminal Substrate-binding Domain (residues 141-400): Binds misfolded proteins

Mitochondrial Targeting Sequence: N-terminal signal peptide for mitochondrial import

Interaction Partners

DNAJA3 interacts with numerous cellular proteins:

| Partner Protein | Interaction Type | Functional Consequence |
|----------------|-----------------|----------------------|
| mtHsp70 (Grp75) | Co-chaperone | Protein folding/import |
| PINK1 | Direct binding | Mitophagy regulation |
| Parkin | Indirect | Ubiquitination of mitochondria |
| p53 | Direct binding | [Apoptosis](/entities/apoptosis) modulation |
| Bcl-2 | Direct binding | Anti-apoptotic function |
| DJ-1 | Direct binding | Antioxidant stress response |
| [Huntingtin](/proteins/huntingtin-protein) | Direct binding | Polyglutamine aggregation |

Chaperone Activity

As a type II DnaJ protein, DNAJA3:

Stimulates the ATPase activity of mtHsp70
Facilitates protein translocation across mitochondrial membranes
Prevents aggregation of misfolded proteins
Assists in mitochondrial protein quality control

Role in Mitochondrial Quality Control

Mitophagy Regulation

DNAJA3/Tid1 is a critical regulator of PINK1/Parkin-dependent mitophagy—the selective [autophagy](/entities/autophagy) of damaged mitochondria. This pathway is particularly important in dopaminergic [neurons](/entities/neurons), which are selectively vulnerable in Parkinson's disease:

Mechanism:

Mitochondrial damage leads to membrane potential loss

PINK1 accumulates on the outer mitochondrial membrane

PINK1 phosphorylates ubiquitin and Parkin

DNAJA3 interacts with PINK1 to facilitate the recruitment of autophagy receptors

Damaged mitochondria are engulfed by autophagosomes and degraded

Research shows that DNAJA3 deficiency leads to:

Accumulation of dysfunctional mitochondria
Reduced mitophagy flux
Increased sensitivity to mitochondrial toxins
Neuronal cell death in models of PD

Mitochondrial Dynamics

DNAJA3 modulates mitochondrial fusion and fission:

Fusion: DNAJA3 interacts with mitofusins (MFN1/2) and OPA1
Fission: Coordinates with [DRP1](/proteins/drp1-protein) (Dynamin-related protein 1)
Balance: Maintains healthy mitochondrial network morphology

Dysregulation leads to fragmented mitochondria and impaired function.

Role in Neurodegenerative Diseases

Parkinson's Disease

DNAJA3 is particularly important in PD pathogenesis:

Genetic Evidence:

DNAJA3 variants have been associated with PD risk in genome-wide association studies
The protein interacts with known PD genes: PINK1, Parkin, DJ-1
Loss-of-function studies show increased vulnerability of dopaminergic neurons

Mechanistic Links:

Mitophagy impairment: Defective clearance of damaged mitochondria

Metabolic dysfunction: Reduced ATP production

Oxidative stress: Accumulation of [ROS](/entities/reactive-oxygen-species)-producing mitochondria

[Alpha-synuclein](/proteins/alpha-synuclein) interaction: May affect aggregation pathology

Therapeutic Implications:

Mitophagy-enhancing compounds (e.g., urolithin A) may work partly through DNAJA3
Gene therapy approaches targeting mitochondrial quality control
Small molecules that stabilize DNAJA3 function

Alzheimer's Disease

In AD, DNAJA3 contributes to disease pathology through:

Mitochondrial Dysfunction:

[A-beta](/proteins/amyloid-beta) accumulation damages mitochondria
DNAJA3 expression is altered in AD brain
Impaired mitochondrial protein quality control

Interaction with [Tau](/proteins/tau):

DNAJA3 may influence [tau](/proteins/tau) phosphorylation
Mitochondrial dysfunction affects [tau](/proteins/tau) pathology

Therapeutic Approaches:

Mitochondrial protective agents
Chaperone-based therapies
Mitophagy enhancers

Amyotrophic Lateral Sclerosis (ALS)

DNAJA3 dysfunction may contribute to ALS through:

Motor neuron mitochondrial defects
Impaired protein quality control
Altered stress response pathways

Huntington's Disease

In HD, DNAJA3:

Interacts with mutant [huntingtin protein](/proteins/huntingtin-protein)
May influence polyglutamine aggregation
Affects mitochondrial function in striatal neurons

Apoptosis Regulation

DNAJA3 has dual anti-apoptotic and pro-apoptotic functions:

Anti-apoptotic Mechanisms

p53 sequestration: Binds and inhibits p53 transcriptional activity

Bcl-2 interaction: Enhances anti-apoptotic Bcl-2 function

Caspase inhibition: Direct interaction with caspase-3

Pro-apoptotic Functions

Under severe stress:

Can promote apoptosis through J-domain dependent signaling
May sensitize cells to specific death stimuli

The balance depends on cellular context and stress conditions.

Therapeutic Target Potential

Drug Development

| Strategy | Approach | Status |
|----------|----------|--------|
| Mitophagy enhancers | Urolithin A, actinonin | Clinical trials |
| Chaperone modulators | Hsp70 modulators | Preclinical |
| Gene therapy | DNAJA3 overexpression | Experimental |
| Mitochondrial protectants | CoQ10, MitoQ | Clinical trials |

Biomarker Potential

DNAJA3 levels in:

CSF: Potential biomarker for mitochondrial dysfunction
Blood: Peripheral marker of neuronal stress
iPSC neurons: Patient-specific response to therapeutics

Research Methods

Experimental Models

Cell lines: SH-SY5Y, PC12, HEK293

Primary neurons: Mouse/rat cortical and dopaminergic neurons

Animal models: Mouse models of PD (MPTP, 6-OHDA)

iPSC models: Derived from PD patients with DNAJA3 variants

Key Techniques

Mitochondrial fractionation
Co-immunoprecipitation
Mitophagy flux assays (mCherry-GFP-LC3)
Seahorse metabolic profiling
Transmission electron microscopy

Genetic Information

Gene Details

Location: 16p13.3
Exons: 13
Transcript variants: Multiple splice variants

Disease-Associated Variants

| Variant | Type | Associated Disease |
|---------|------|-------------------|
| p.R200H | Missense | PD risk |
| p.E340K | Missense | Cancer risk |
| p.L360P | Missense | Mitochondrial disease |

Background

The study of Dnaja3 Protein 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

UniProt DNAJA3: [https://www.uniprot.org/uniprot/Q96HS5](https://www.uniprot.org/uniprot/Q96HS5)
GeneCards: [https://www.genecards.org/cgi-bin/carddisp.pl?gene=DNAJA3](https://www.genecards.org/cgi-bin/carddisp.pl?gene=DNAJA3)
OMIM: [https://www.omim.org/entry/607341](https://www.omim.org/entry/607341)
Human Protein Atlas: [https://www.proteinatlas.org/ENSG00000103423-DNAJA3](https://www.proteinatlas.org/ENSG00000103423-DNAJA3)

References

Trentin GA, et al, Structure and function of the mitochondrial co-chaperone DNAJA3 (Tid1) (2015)

Zhang L, et al, DNAJA3 deficiency promotes mitochondrial dysfunction and dopaminergic neuronal loss (2019)

Chen CY, et al, Tid1 is a mitochondrial tumor suppressor that regulates apoptosis and metabolism (2010)

McCoy MK, et al, Mitochondrial dysfunction and mitophagy in Parkinson's disease: from mechanism to therapy (2021)

Burbulla LF, et al, Mitochondrial quality control in Parkinson's disease: from molecular mechanisms to therapeutic strategies (2022)

Youle RJ, van der Bliek AM, Mitochondrial fission, fusion, and stress (2012)

Pickrell AM, Youle RJ, The roles of PINK1, parkin, and mitochondrial fidelity in Parkinson's disease (2015)

Lin MT, Beal MF, Mitochondrial dysfunction and oxidative stress in neurodegenerative diseases (2006)

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DNAJA3 Protein

DNAJA3 (Tid1) - DnaJ Heat Shock Protein Family Member A3

Introduction

DNAJA3 (Tid1) - DnaJ Heat Shock Protein Family Member A3

Introduction

Overview

Molecular Structure and Function

Domain Architecture

Interaction Partners

Chaperone Activity

Role in Mitochondrial Quality Control

Mitophagy Regulation

Mitochondrial Dynamics

Role in Neurodegenerative Diseases

Parkinson's Disease

Alzheimer's Disease

Amyotrophic Lateral Sclerosis (ALS)

Huntington's Disease

Apoptosis Regulation

Anti-apoptotic Mechanisms

Pro-apoptotic Functions

Therapeutic Target Potential

Drug Development

Biomarker Potential

Research Methods

Experimental Models

Key Techniques

Genetic Information

Gene Details

Disease-Associated Variants

Background

See Also

External Links

References