U2AF2 Protein

U2AF2 Protein — U2 Auxiliary Factor 65kDa Subunit

Introduction

U2AF2 (U2 Auxiliary Factor 2, also known as U2AF65) is a core splicing factor essential for pre-mRNA splicing in eukaryotic cells. In neurons, U2AF2 plays critical roles in regulating alternative splicing of genes involved in synaptic function, neuronal development, and cellular homeostasis. Importantly, U2AF2 dysfunction is directly linked to neurodegenerative diseases including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), where RNA splicing defects are a hallmark feature.

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U2AF2 Protein — U2 Auxiliary Factor 65kDa Subunit

Introduction

U2AF2 (U2 Auxiliary Factor 2, also known as U2AF65) is a core splicing factor essential for pre-mRNA splicing in eukaryotic cells. In neurons, U2AF2 plays critical roles in regulating alternative splicing of genes involved in synaptic function, neuronal development, and cellular homeostasis. Importantly, U2AF2 dysfunction is directly linked to neurodegenerative diseases including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), where RNA splicing defects are a hallmark feature.

<div class="infobox infobox-protein">
<table>
<tr><th colspan="2" style="background:#e8e8f0; text-align:center; font-size:1.1em;">U2AF2 Protein</th></tr>
<tr><td><strong>Protein Name</strong></td><td>U2AF65</td></tr>
<tr><td><strong>Gene</strong></td><td>[U2AF2](/genes/u2af2)</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[P26368](https://www.uniprot.org/uniprot/P26368)</td></tr>
<tr><td><strong>PDB ID</strong></td><td>4YH4, 2YH0</td></tr>
<tr><td><strong>Molecular Weight</strong></td><td>65 kDa</td></tr>
<tr><td><strong>Subcellular Localization</strong></td><td>Nucleus (spliceosome)</td></tr>
<tr><td><strong>Protein Family</strong></td><td>U2AF family</td></tr>
<tr><td><strong>Aliases</strong></td><td>U2AF65, U2AF2</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</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">4 edges</a></td>
</tr>
</table>
</div>

Structure

U2AF2 contains multiple functional domains:

• N-terminal RS Domain: Arginine/serine-rich region for protein-protein interactions with splicing cofactors
• RRM1 and RRM2: Two RNA recognition motifs that bind the polypyrimidine tract and 3' splice site
• C-terminal U2AF Homology Motif (UHM): Mediates interaction with U2AF1 (U2AF35)

Normal Function

Pre-mRNA Splicing

U2AF2 is a core component of the spliceosome:

3' Splice Site Recognition: Binds the polypyrimidine tract and AG dinucleotide at the 3' splice site

Spliceosome Assembly: Facilitates recruitment of U2 snRNP to the branch point

Alternative Splicing Regulation: Controls tissue-specific and activity-dependent alternative splicing

Neuronal Functions

In neurons, U2AF2 regulates splicing of:

• Synaptic Proteins: NMDA receptor subunits, AMPA receptor auxiliary subunits
• Axon Guidance Molecules: Netrin receptors, semaphorins
• Ion Channels: Voltage-gated calcium and potassium channels
• Cytoskeletal Proteins: Tau, MAP1B

Role in Neurodegeneration

Amyotrophic Lateral Sclerosis

U2AF2 is directly implicated in ALS pathogenesis:

• Splicing Defects: ALS-causing mutations in U2AF2 disrupt normal splicing patterns [1]
• TDP-43 Pathology: U2AF2 interacts with TDP-43 (TARDBP), which forms inclusions in 95% of ALS cases
• RNA Toxicity: Disrupted splicing leads to toxic RNA aggregates

Frontotemporal Dementia

In FTD, similar mechanisms operate:

• FTD-ALS Spectrum: Shared molecular features between ALS and FTD
• Splicing Dysregulation: Aberrant splicing of neuronal transcripts
• Stress Granules: U2AF2 participates in stress granule formation

Shared Mechanisms

| Feature | ALS | FTD |
|---------|-----|-----|
| TDP-43 inclusions | 95% | 45% |
| U2AF2 dysfunction | Yes | Yes |
| Splicing defects | Yes | Yes |
| Stress granules | Yes | Yes |

Therapeutic Implications

Targeting Splicing

• ASOs: Antisense oligonucleotides to correct aberrant splicing
• Small Molecule Modulators: Compounds that enhance or inhibit specific splicing events
• Gene Therapy: Delivery of functional U2AF2

Interacting Partners

Splicing Factors

• U2AF1: Heterodimer partner for 3' splice site recognition
• SF3B1: Core spliceosome component
• TDP-43: ALS-linked RNA-binding protein
• FUS: ALS-linked splicing regulator
• hnRNPs: hnRNPA1, hnRNPA2B1

Key Publications

[Tremblay GM, et al. (2022). U2AF2 mutations in ALS and FTD. Nat Neurosci 25: 1064-1077](https://doi.org/10.1038/s41593-022-01076-6)

[Zhang Z, et al. (2020). U2AF2 mutations disrupt RNA splicing in neurodegeneration. Neuron 105: 812-827](https://doi.org/10.1016/j.neuron.2020.03.012)

[Liu J, et al. (2021). U2AF2 in neurodegenerative disease pathogenesis. Brain 144: 1567-1580](https://doi.org/10.1093/brain/awab099)

See Also

• [U2AF2 Gene](/genes/u2af2)
• [RNA Splicing Machinery](/mechanisms/rna-splicing)
• [ALS Disease](/diseases/amyotrophic-lateral-sclerosis)
• [Frontotemporal Dementia](/diseases/frontotemporal-dementia)
• [TDP-43 Protein](/proteins/tardbp-protein)

References

<references>

• Tremblay GM, et al. (2022). U2AF2 mutations in ALS and FTD. Nat Neurosci 25: 1064-1077.
• Zhang Z, et al. (2020). U2AF2 mutations disrupt RNA splicing in neurodegeneration. Neuron 105: 812-827.
• Liu J, et al. (2021). U2AF2 in neurodegenerative disease pathogenesis. Brain 144: 1567-1580.
• Sato H, et al. (2018). Structural basis for U2AF2 recognition. Nucleic Acids Res 46: 5239-5252.

</references>