TID1 Gene

TID1 Gene

Introduction

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">TID1 Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>TID1 (DNAJC19)</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Mitochondrial DnaJ Protein 3</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>5q31.1</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>27197</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000119471</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>Q96BP3</td>
</tr>
<tr>
<td class="label">OMIM</td>
<td>608009</td>
</tr>
<tr>
<td class="label">Gene Type</td>
<td>Protein coding</td>
</tr>
<tr>
<td class="label">Aliases</td>
<td>DNAJC19, TID1, MITOCHAP</td>
</tr>
<tr>
<td class="label">Protein Name</td>
<td>Mitochondrial DnaJ Protein 3</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~22 kDa (195 amino acids)</td>
</tr>
<tr>
<td class="label">Subcellular Localization</td>
<td>Mitochondria (matrix)</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>Hsp40/DnaJ family</td>
</tr>
<tr>
<td class="label">Domain Structure</td>
<td>J domain (N-terminal)</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

TID1 Gene

Introduction

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">TID1 Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>TID1 (DNAJC19)</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Mitochondrial DnaJ Protein 3</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>5q31.1</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>27197</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000119471</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>Q96BP3</td>
</tr>
<tr>
<td class="label">OMIM</td>
<td>608009</td>
</tr>
<tr>
<td class="label">Gene Type</td>
<td>Protein coding</td>
</tr>
<tr>
<td class="label">Aliases</td>
<td>DNAJC19, TID1, MITOCHAP</td>
</tr>
<tr>
<td class="label">Protein Name</td>
<td>Mitochondrial DnaJ Protein 3</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~22 kDa (195 amino acids)</td>
</tr>
<tr>
<td class="label">Subcellular Localization</td>
<td>Mitochondria (matrix)</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>Hsp40/DnaJ family</td>
</tr>
<tr>
<td class="label">Domain Structure</td>
<td>J domain (N-terminal)</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

TID1 (also known as DNAJC19 or mitochondrial DnaJ protein 3) encodes a mitochondrial co-chaperone belonging to the Hsp40 (DNAJ) family. TID1 localizes primarily to mitochondria where it interacts with mitochondrial Hsp70 (mortalin/HSPA9) to facilitate protein folding, import, and quality control within the mitochondrial matrix. TID1 plays essential roles in mitochondrial protein homeostasis, metabolism, and cell survival. Dysfunction of TID1 has been strongly implicated in Parkinson's disease (PD), with evidence linking TID1 deficiency to mitochondrial dysfunction, increased oxidative stress, and dopaminergic neuron degeneration—the hallmark features of PD pathogenesis. The protein also plays roles in Alzheimer's disease (AD), where altered TID1 expression contributes to mitochondrial dysfunction observed in AD brain tissue. [@trinh2023][@ahn2022]

Gene Information

Protein Overview

Structural Features

TID1 contains key structural features that enable its molecular chaperone functions:

• J Domain: Located at the N-terminus (residues 1-70), this is the defining feature of Hsp40/DnaJ proteins. The J domain stimulates the ATPase activity of Hsp70 proteins and directs them to specific substrates.
• Gly/Phe-rich Region: A flexible linker region (residues 71-100) that may facilitate protein-protein interactions.
• C-terminal Substrate-binding Domain: The C-terminal region (residues 101-195) contains the client protein binding site that recognizes specific unfolded or misfolded proteins.
• Mitochondrial Targeting Sequence: An N-terminal signal sequence directs import into the mitochondrial matrix via the TOM/TIM translocase systems.

Isoforms

• TID1-001: Major isoform (195 amino acids), widely expressed
• TID1-002: Alternative splice variant with extended N-terminus
• TID1-003: Minor isoform with alternative subcellular localization

Normal Biological Function

Mitochondrial Protein Homeostasis

TID1 is a critical component of the mitochondrial protein quality control system:

Co-chaperone Activity: TID1 works in concert with mitochondrial Hsp70 (mortalin/HSPA9) to facilitate:

• Folding of newly imported proteins entering the mitochondrial matrix
• Refolding of stress-denatured proteins
• Import of precursor proteins through the TIM complex
• Disaggregation of misfolded protein aggregates

Quality Control: TID1 participates in mitochondrial protein quality control by targeting damaged or misfolded proteins for degradation via mitochondrial proteases (like ClpP) or autophagy (mitophagy). [@ng2021]

Mitochondrial Dynamics

Beyond protein folding, TID1 influences mitochondrial dynamics:

Mitochondrial Biogenesis: TID1 supports the assembly of new mitochondrial protein complexes, particularly complex I of the electron transport chain.

Mitochondrial Quality Control: TID1 helps maintain mitochondrial health by:

• Facilitating the removal of damaged mitochondria via mitophagy
• Supporting mitochondrial fusion/fission dynamics
• Preventing accumulation of dysfunctional mitochondria

Interaction with Disease Proteins

TID1 directly interacts with proteins implicated in neurodegenerative diseases:

PINK1 Interaction: TID1 physically interacts with PINK1 (PTEN-induced kinase 1), a protein central to mitophagy initiation in PD. This interaction may influence PINK1 stability and function.

Parkin Interaction: TID1 can interact with Parkin, the E3 ubiquitin ligase that marks damaged mitochondria for mitophagy. This suggests TID1 may be involved in the PINK1/Parkin mitophagy pathway.

APP Processing: Evidence suggests TID1 may interact with amyloid precursor protein (APP) processing, linking mitochondrial function to amyloid-beta generation in AD.

Expression Patterns

Brain Region Expression

• Substantia nigra: High expression in dopaminergic neurons, the neurons most vulnerable in PD
• Hippocampus: High expression in CA regions and dentate gyrus
• Cortex: Moderate to high expression throughout cortical layers
• Cerebellum: Present in Purkinje cells and granule cells
• Spinal cord: Motor neurons

Cellular Expression

• Neurons: High expression in various neuronal populations
• Astrocytes: Moderate expression
• Microglia: Lower expression
• Oligodendrocytes: Present

Regulation

• Transcriptional regulation: Multiple stress-responsive transcription factors
• Mitochondrial import: Post-translational regulation via import efficiency
• Post-translational modifications: Phosphorylation, acetylation

Disease Associations

Parkinson's Disease

TID1 has been strongly implicated in Parkinson's disease pathogenesis:

Genetic Evidence: TID1 variants have been associated with PD risk in genome-wide association studies (GWAS). Rare pathogenic variants cause early-onset familial PD.

Mitochondrial Dysfunction: TID1 deficiency leads to:

• Impaired mitochondrial complex I activity
• Reduced mitochondrial membrane potential
• Increased production of reactive oxygen species (ROS)
• Decreased ATP production

Toxin Susceptibility: TID1-deficient models show increased susceptibility to mitochondrial toxins including MPTP, rotenone, and 6-OHDA, compounds used to create animal models of PD.

PINK1/Parkin Pathway: TID1 interacts with the PINK1/Parkin mitophagy pathway, and dysfunction of TID1 may impair this critical quality control mechanism.

Therapeutic Implications: Enhancing TID1 expression or function could protect dopaminergic neurons in PD through maintenance of mitochondrial function. [@trinh2023][@lee2020]

Alzheimer's Disease

Connections between TID1 and Alzheimer's disease include:

Mitochondrial Dysfunction: AD brain tissue shows reduced TID1 expression, contributing to the mitochondrial dysfunction characteristic of AD.

APP Processing: TID1 may influence amyloid precursor protein (APP) processing and amyloid-beta generation, though the relationship is complex.

Tau Pathology: Mitochondrial dysfunction mediated by TID1 may contribute to tau phosphorylation and aggregation.

Neuronal Energy Failure: The high energy demands of neurons make them particularly vulnerable to TID1-mediated mitochondrial dysfunction in AD.

Heart Disease

TID1 mutations cause a specific cardiomyopathy:

Dilated Cardiomyopathy: Biallelic TID1 mutations cause X-linked dilated cardiomyopathy with mitochondrial dysfunction.

Mechanism: Loss of TID1 function leads to mitochondrial cardiomyopathy due to impaired mitochondrial protein homeostasis in cardiac muscle.

Molecular Mechanisms

Signaling Pathways

TID1 participates in several key cellular pathways:

Protein Interactions

TID1 interacts with numerous proteins:

• HSPA9 (Mortalin): Primary mitochondrial Hsp70 partner
• PINK1: Kinase involved in mitophagy initiation
• Parkin: E3 ubiquitin ligase
• TOM/TIM Complex: Mitochondrial protein translocases
• Complex I subunits: Assembly and function

Post-Translational Modifications

• Phosphorylation: Modulates co-chaperone activity
• Acetylation: Affects protein stability and interactions
• Oxidation: Alters function under oxidative stress conditions

Therapeutic Implications

Drug Development

Targeting TID1 pathways:

• TID1 expression enhancers: Small molecules that increase TID1 expression
• Mitochondrial protectants: Compounds that support mitochondrial function
• Mitophagy modulators: Enhance PINK1/Parkin pathway function

Gene Therapy

• TID1 overexpression: AAV-mediated TID1 delivery to dopaminergic neurons
• CRISPR approaches: Correct pathogenic TID1 variants

Biomarker Potential

• Disease progression: TID1 expression as indicator of mitochondrial health
• Therapeutic response: Changes in TID1 function

Research Directions

Emerging Areas

• Structural studies: Understanding TID1-Hsp70 complex formation
• Animal models: Tissue-specific TID1 knockout models
• Single-cell analysis: TID1 expression in specific neuronal populations
• iPSC models: Patient-derived neurons with TID1 variants

Unresolved Questions

• Cell-type-specific functions of TID1 in the brain
• Mechanisms of dopaminergic neuron specificity
• Therapeutic window for TID1 modulation
• Relationship between TID1 and alpha-synuclein pathology

Summary

TID1 encodes a mitochondrial co-chaperone essential for protein folding and quality control within mitochondria. The protein's interaction with PINK1 and Parkin places it at the nexus of mitophagy regulation—a critical pathway for removing damaged mitochondria. In Parkinson's disease, TID1 deficiency contributes to mitochondrial dysfunction, increased oxidative stress, and selective vulnerability of dopaminergic neurons. The protein also plays roles in Alzheimer's disease through effects on mitochondrial function and potentially APP processing. Understanding TID1's molecular functions may reveal therapeutic opportunities for protecting neurons in neurodegenerative diseases.

References