AIFM2 — Apoptosis-Inducing Factor Mitochondria-Like 2

AIFM2 — Apoptosis-Inducing Factor Mitochondria-Like 2

Overview

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">AIFM2 — Apoptosis-Inducing Factor Mitochondria-Like 2</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>AIFM2</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>AIFM2 — Apoptosis-Inducing Factor Mitochondria-Like 2</td>
</tr>
<tr>
<td class="label">Type</td>
<td>Gene</td>
</tr>
<tr>
<td class="label">NCBI</td>
<td><a href="https://www.ncbi.nlm.nih.gov/gene/?term=AIFM2" target="_blank">Search NCBI</a></td>
</tr>
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<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

AIFM2 (Apoptosis-Inducing Factor Mitochondria-Like 2), also known as AMID (Apoptosis-Inducing Factor Mitochondria-Like), is a mitochondrial flavoprotein homologous to AIFM1 (Apoptosis-Inducing Factor Mitochondria 1). While first discovered as a pro-apoptotic protein, AIFM2 has emerged as a multifunctional protein involved in caspase-independent [apoptosis](/entities/apoptosis), [oxidative stress](/mechanisms/oxidative-stress) response, NADH oxidation, and mitochondrial metabolism. First identified in 2000 by Dugas et al., AIFM2 represents a unique branch of the cell death machinery distinct from classical caspase-dependent pathways[@daugas2000].

Gene and Protein Structure

Gene Location and Organization

AIFM2 — Apoptosis-Inducing Factor Mitochondria-Like 2

Overview

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">AIFM2 — Apoptosis-Inducing Factor Mitochondria-Like 2</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>AIFM2</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>AIFM2 — Apoptosis-Inducing Factor Mitochondria-Like 2</td>
</tr>
<tr>
<td class="label">Type</td>
<td>Gene</td>
</tr>
<tr>
<td class="label">NCBI</td>
<td><a href="https://www.ncbi.nlm.nih.gov/gene/?term=AIFM2" target="_blank">Search NCBI</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

AIFM2 (Apoptosis-Inducing Factor Mitochondria-Like 2), also known as AMID (Apoptosis-Inducing Factor Mitochondria-Like), is a mitochondrial flavoprotein homologous to AIFM1 (Apoptosis-Inducing Factor Mitochondria 1). While first discovered as a pro-apoptotic protein, AIFM2 has emerged as a multifunctional protein involved in caspase-independent [apoptosis](/entities/apoptosis), [oxidative stress](/mechanisms/oxidative-stress) response, NADH oxidation, and mitochondrial metabolism. First identified in 2000 by Dugas et al., AIFM2 represents a unique branch of the cell death machinery distinct from classical caspase-dependent pathways[@daugas2000].

Gene and Protein Structure

Gene Location and Organization

The AIFM2 gene is located on chromosome 10q22.2 and encodes a 480-amino acid protein with a molecular weight of approximately 53 kDa. The protein shares approximately 30% sequence identity with AIFM1 but has distinct structural features and functional properties.

Protein Domains

AIFM2 contains:

• N-terminal mitochondrial targeting sequence: Directs import to mitochondria
• FAD-binding domain: Essential for oxidoreductase activity
• NADH-binding site: Enables electron transfer reactions
• C-terminal domain: Involved in protein-protein interactions

Biological Functions

NADH Oxidoreductase Activity

AIFM2 functions as an NAD(P)H-dependent oxidoreductase, catalyzing electron transfer reactions in mitochondria. This activity is crucial for:

• Mitochondrial respiration: Contributes to electron transport chain function
• Redox balance: Helps maintain cellular NAD+/NADH ratios
• Metabolic regulation: Links energy metabolism to cell survival decisions

Caspade-Independent Apoptosis

Like AIFM1, AIFM2 can induce caspase-independent cell death under certain conditions. The mechanism involves:

However, AIFM2 and AIFM1 have distinct kinetic and regulatory properties, with AIFM2 often showing delayed or context-dependent pro-apoptotic activity.

Antioxidant Defense

AIFM2 plays a protective role against [oxidative stress](/mechanisms/oxidative-stress):

• Scavenges reactive oxygen species (ROS)
• Maintains mitochondrial membrane potential
• Protects against ROS-induced cell death
• Complements glutathione peroxidase activities

Mitochondrial Function

AIFM2 affects multiple aspects of mitochondrial biology:

• Mitochondrial membrane potential: Stabilization
• ATP production: Regulation of oxidative phosphorylation
• Calcium homeostasis: Modulation of calcium handling
• Mitochondrial dynamics: Influence on fission/fusion balance

Role in Neurodegeneration

Alzheimer's Disease

In [Alzheimer's disease](/diseases/alzheimers-disease), AIFM2 expression and function are altered in ways that may contribute to disease pathogenesis:

The interplay between AIFM2 and amyloid pathology is complex, with both protective and detrimental effects depending on disease stage and cellular context[@du2016].

Parkinson's Disease

In [Parkinson's disease](/diseases/parkinsons-disease), AIFM2 may play important roles:

AIFM2 dysregulation has been documented in PD models and patient samples, suggesting a role in disease pathogenesis[@hangen2015].

Other Neurodegenerative Disorders

• Huntington's disease: Altered expression in affected brain regions
• Amyotrophic lateral sclerosis (ALS): Contributes to motor neuron death
• Retinal degeneration: AIF-mediated cell death in photoreceptor loss[@ye2019]
• Stroke: Role in ischemic neuronal injury

Disease Associations Beyond Neurodegeneration

Cancer

AIFM2 has complex, often dual roles in cancer:

Metabolic Disorders

• Diabetes: Altered expression in diabetic complications
• Metabolic syndrome: Connections to oxidative stress
• Obesity: May affect adipose tissue function

Cardiovascular Disease

• Ischemia-reperfusion injury: Mediates cardiac cell death
• Atherosclerosis: Role in vascular cell survival
• Heart failure: Altered expression in failing myocardium

Expression Patterns

Tissue Distribution

AIFM2 shows broad expression across tissues:

• High expression: Brain, heart, skeletal muscle, liver
• Moderate expression: Kidney, lung, spleen
• Low expression: Most other tissues

Brain Regional Expression

Within the brain:

• Cortex: Moderate-high expression in pyramidal neurons
• Hippocampus: High expression in CA1-CA3 neurons
• Cerebellum: Prominent in Purkinje cells
• Basal ganglia: Expression in dopaminergic regions

Regulation

AIFM2 expression is regulated by:

• Transcriptional factors: p53, NF-κB
• Stress conditions: Oxidative stress upregulates expression
• Developmental cues: Higher expression during development
• Cell cycle: Cell cycle-dependent regulation

Therapeutic Implications

Targeting AIFM2 in Neurodegeneration

Therapeutic strategies targeting AIFM2 include:

Cancer Therapy

• Chemosensitization: Modulating AIFM2 to enhance drug efficacy
• Synthetic lethality: Targeting cancer cells with high AIFM2 dependence

Biomarker Potential

• Disease progression: AIFM2 levels as biomarker
• Treatment response: Monitoring therapeutic efficacy

Key Publications

Cross-References

• [Apoptosis](/entities/apoptosis)
• [Mitochondrial Dysfunction](/mechanisms/mitochondrial-dysfunction)
• [Oxidative Stress](/mechanisms/oxidative-stress)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Cell Death Pathways](/mechanisms/cell-death-pathways)

See Also

• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [ALS](/diseases/amyotrophic-lateral-sclerosis)
• [Mitochondrial Dysfunction](/mechanisms/mitochondrial-dysfunction)
• [Oxidative Stress](/mechanisms/oxidative-stress)
• [Cell Death Mechanisms](/mechanisms/cell-death-pathways)

External Links

• [NCBI Gene: AIFM2](https://www.ncbi.nlm.nih.gov/gene/128229)
• [UniProt: Q9Y2E5](https://www.uniprot.org/uniprot/Q9Y2E5)
• [GeneCards: AIFM2](https://www.genecards.org/cgi-bin/carddisp.pl?gene=AIFM2)
• [Ensembl: ENSG00000095139](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000095139)

Allen Brain Atlas Resources

• [Human Brain Atlas - AIFM2 Expression](https://human.brain-map.org/microarray/search/show?search_term=AIM2): Gene expression data in human brain
• [BrainSpan Atlas](https://www.brainspan.org/static/download.html): Developmental transcriptome data for AIFM2

References