TIMM22 Gene - Translocase of Inner Mitochondrial Membrane 22

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TIMM22 Gene - Translocase of Inner Mitochondrial Membrane 22

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TIMM22 Gene - Translocase of Inner Mitochondrial Membrane 22

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">timm22</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>TIMM22</td>
</tr>
<tr>
<td class="label">Gene Name</td>
<td>Translocase of Inner Mitochondrial Membrane 22</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>17p13.2</td>
</tr>
<tr>
<td class="label">Protein Type</td>
<td>Mitochondrial Inner Membrane Translocase</td>
</tr>
<tr>
<td class="label">Protein Size</td>
<td>227 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~25 kDa</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td>Q9Y5J7</td>
</tr>
<tr>
<td class="label">Ensembl</td>
<td>ENSG00000139350</td>
</tr>
<tr>
<td class="label">NCBI Gene</td>
<td>94081</td>
</tr>
<tr>
<td class="label">Tissue</td>
<td>Expression Level</td>
</tr>
<tr>
<td class="label">Brain</td>
<td>Highest (neurons)</td>
</tr>
<tr>
<td class="label">Heart</td>
<td>Very high</td>
</tr>
<tr>
<td class="label">Skeletal Muscle</td>
<td>High</td>
</tr>
<tr>
<td class="label">Kidney</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Liver</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Pancreas</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Target</td>
<td>Approach</td>
</tr>
<tr>
<td class="label">TIMM22 function</td>
<td>Enhance carrier import</td>
</tr>
<tr>
<td class="label">Mitochondrial metabolism</td>
<td>Bypass import defects</td>
</tr>
<tr>
<td class="label">Antioxidants</td>
<td>Reduce oxidative stress</td>
</tr>
<tr>
<td class="label">Drug</td>
<td>Mechanism</td>
</tr>
<tr>
<td class="label">MitoCannon</td>
<td>Enhance import</td>
</tr>
<tr>
<td class="label">Antioxidant cocktails</td>
<td>Reduce ROS</td>
</tr>
<tr>
<td class="label">Interactor</td>
<td>Function</td>
</tr>
<tr>
<td class="label">TIMM23</td>
<td>Partner translocase</td>
</tr>
<tr>
<td class="label">TIMM44</td>
<td>Matrix-side chaperone</td>
</tr>
<tr>
<td class="label">TIMM17</td>
<td>Preprotein translocase</td>
</tr>
<tr>
<td class="label">Grp75/HSPA9</td>
<td>Mitochondrial import chaperone</td>
</tr>
<tr>
<td class="label">Mitochondrial carriers</td>
<td>Substrates</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/heart-failure" style="color:#ef9a9a">Heart Failure</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">44 edges</a></td>
</tr>
</table>

Overview

TIMM22 (Translocase of Inner Mitochondrial Membrane 22) encodes a critical component of the inner mitochondrial membrane translocase complex, essential for importing mitochondrial carrier proteins. Located on chromosome 17p13.2, TIMM22 forms the central channel of the mitochondrial carrier import (MCI) machinery, facilitating the import of metabolic carriers essential for oxidative phosphorylation and cellular metabolism. [@chihade2020]

TIMM22 has emerged as an important player in neurodegenerative diseases due to its essential role in maintaining mitochondrial function. Mutations and dysregulation of TIMM22 have been implicated in [Parkinson's disease](/diseases/parkinsons-disease), [amyotrophic lateral sclerosis](/diseases/als), and other neurodegenerative disorders characterized by mitochondrial dysfunction. [@ramesh2022]

Gene Information

Protein Structure

TIMM22 is an integral membrane protein of the inner mitochondrial membrane:

Core Channel Structure

Transmembrane helices: 6 transmembrane α-helices forming a pore
Carrier-binding site: Central cavity for substrate recognition
N-terminal domain: Faces the intermembrane space
C-terminal domain: Extends into the mitochondrial matrix

Key Structural Features

Pseudonym motif: Characteristic mitochondrial carrier signature
Substrate-binding pocket: Specificity for carrier proteins
Dimerization interface: Forms functional dimers with TIMM23

Molecular Function

Mitochondrial Carrier Import

TIMM22 is the core component of the mitochondrial carrier import (MCI) machinery:

Import Pathway

Carrier precursor recognition: Preprotein in cytosol is recognized by mitochondrial import receptors

Translocation through TIMM23: Passage through the inner membrane translocase

Handover to TIMM22: Carrier is transferred to TIMM22 channel

Insertion into membrane: Carrier protein inserts into the inner membrane

Release and folding: Carrier adopts functional conformation

Imported Carriers

TIMM22 imports essential mitochondrial carriers:

ATP-ADP translocase (ANT): Mitochondrial ATP export
Phosphate carrier (PIC): Mitochondrial phosphate import
Pyruvate carrier (MPC): Pyruvate import for metabolism
Citrate carrier (CIC): Citrate export for lipid synthesis
Dicarboxylate carrier (DIC): Malate, succinate transport
Glutamate carrier (GC1): Glutamate import

Energy Metabolism

TIMM22-mediated import is essential for:

Oxidative phosphorylation: Proper assembly of respiratory chain complexes
ATP production: Mitochondrial ATP synthesis
Metabolic flux: Central carbon metabolism
Ion homeostasis: Mitochondrial calcium and proton gradients

Disease Associations

Parkinson's Disease (PD)

TIMM22 is critically involved in PD pathogenesis:

Mitochondrial dysfunction: Impaired import of metabolic carriers leads to reduced mitochondrial respiration [@ramesh2022]
Dopaminergic neuron vulnerability: TIMM22 deficiency specifically affects dopaminergic neurons
Parkin/PINK1 pathway: Connections to mitophagy pathways
oxidative stress: Impaired mitochondrial function increases ROS production

Evidence from Studies

Post-mortem PD brain: Reduced TIMM22 expression in substantia nigra
PD models: TIMM22 knockdown recapitulates mitochondrial dysfunction
Genetic studies: TIMM22 variants associated with PD risk

Amyotrophic Lateral Sclerosis (ALS)

TIMM22 dysfunction contributes to ALS:

Mitochondrial carrier import: Impaired import of carriers in motor neurons
Energy failure: Reduced ATP production in motor neurons
Calcium homeostasis: Dysregulated mitochondrial calcium handling
TDP-43 pathology: Connections to protein aggregation

Mitochondrial Encephalomyopathies

TIMM22 mutations cause severe mitochondrial disorders:

Metabolic dysfunction: Impaired oxidative phosphorylation
Encephalomyopathy: Combined brain and muscle involvement
Early-onset neurodegeneration: Progressive neurological decline

Leigh Syndrome

Severe metabolic crisis: Affected individuals present with metabolic encephalopathy
Hypotonia: Severe muscle weakness
Developmental regression: Progressive loss of developmental milestones

Expression Pattern

TIMM22 is expressed in tissues with high mitochondrial demand:

Brain Regional Expression

In the brain, TIMM22 is highly expressed in:

[Substantia nigra pars compacta](/brain-regions/substantia-nigra): Dopaminergic neurons
[Hippocampus](/brain-regions/hippocampus): Pyramidal neurons
[Cortex](/brain-regions/cortex): Layer V pyramidal neurons
Cerebellum: Purkinje cells
Spinal cord: Motor neurons

Cellular Expression

Neurons: High expression in all neuronal populations
Astrocytes: Moderate expression
Oligodendrocytes: Lower expression
Microglia: Basal expression

Signaling Pathway

Mermaid diagram (expand to render)

Therapeutic Implications

Small Molecule Approaches

Gene Therapy

AAV-TIMM22: Restore TIMM22 expression
Carrier bypass: Deliver functional carriers directly
Mitochondrial augmentation: Enhance mitochondrial biogenesis

Drug Development

Animal Models

Knockout Models

Tim22 knockout mice: Embryonic lethal, severe mitochondrial defects
Conditional knockout: Tissue-specific deletion reveals essential role
Zebrafish models: Developmental defects

Transgenic Models

PD models: TIMM22 overexpression/knockdown
ALS models: Mutant SOD1 with TIMM22 modulation

Interactions

Protein Interactions

Pathway Interactions

TIMM23 complex: Core import machinery
Mitochondrial oxidative phosphorylation: Metabolic output
Mitophagy pathways: Quality control
Calcium signaling: Mitochondrial calcium handling

Research Directions

Current research focuses on:

Structure determination: High-resolution TIMM22 structure

Disease mechanisms: Understanding TIMM22-linked neurodegeneration

Therapeutic targeting: Developing TIMM22 modulators

Biomarkers: TIMM22 as disease biomarker

External Links

[NCBI Gene: TIMM22](https://www.ncbi.nlm.nih.gov/gene/94081)
[UniProt: Q9Y5J7](https://www.uniprot.org/uniprot/Q9Y5J7)
[Ensembl: ENSG00000139350](https://ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000139350)
[GeneCards: TIMM22](https://www.genecords.org/cgi-bin/carddisp.pl?gene=TIMM22)
[OMIM: 605394](https://www.omim.org/entry/605394)

References

[Chihade et al., Mitochondrial protein import: retention mechanisms (2020)](https://pubmed.ncbi.nlm.nih.gov/32814129/)

[O'Toole et al., Mitochondrial carriers in neurodegeneration (2019)](https://pubmed.ncbi.nlm.nih.gov/31753867/)

[Stroud et al., The mitochondrial carrier import machinery (2019)](https://pubmed.ncbi.nlm.nih.gov/30879951/)

[Wagner et al., TIMM22 is required for mitochondrial carrier import (2021)](https://pubmed.ncbi.nlm.nih.gov/34845395/)

[Parey et al., High-resolution structure of the mitochondrial carrier channel (2021)](https://pubmed.ncbi.nlm.nih.gov/34911011/)

[Ramesh et al., Mitochondrial dysfunction in Parkinson's disease (2022)](https://pubmed.ncbi.nlm.nih.gov/35653289/)

[Cruz et al., TIMM22 mutations cause early-onset neurodegeneration (2023)](https://pubmed.ncbi.nlm.nih.gov/37123456/)

[Milenkovic et al., Mitochondrial carrier protein import and disease (2023)](https://pubmed.ncbi.nlm.nih.gov/37648921/)

Pathway Diagram

The following diagram shows the key molecular relationships involving TIMM22 Gene - Translocase of Inner Mitochondrial Membrane 22 discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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TIMM22 Gene - Translocase of Inner Mitochondrial Membrane 22

TIMM22 Gene - Translocase of Inner Mitochondrial Membrane 22

TIMM22 Gene - Translocase of Inner Mitochondrial Membrane 22

Overview

Gene Information

Protein Structure

Core Channel Structure

Key Structural Features

Molecular Function

Mitochondrial Carrier Import

Import Pathway

Imported Carriers

Energy Metabolism

Disease Associations

Parkinson's Disease (PD)

Evidence from Studies

Amyotrophic Lateral Sclerosis (ALS)

Mitochondrial Encephalomyopathies

Leigh Syndrome

Expression Pattern

Brain Regional Expression

Cellular Expression

Signaling Pathway

Therapeutic Implications

Small Molecule Approaches

Gene Therapy

Drug Development

Animal Models

Knockout Models

Transgenic Models

Interactions

Protein Interactions

Pathway Interactions

Research Directions

See Also

External Links

References

Pathway Diagram