ELAVL4 Protein

ELAVL4 Protein

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">ELAV-Like Protein 4</th>
</tr>
<tr> [@elavl2016]
<td class="label">Protein Name</td> [@brain2020]
<td>ELAV-Like Protein 4 (HuD)</td> [@tdp2020]
</tr> [@elavl2020]
<tr>
<td class="label">Gene</td>
<td>[ELAVL4](/genes/elavl4)</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td><a href="https://www.uniprot.org/uniprot/P26378" target="_blank">P26378</a></td>
</tr>
<tr>
<td class="label">PDB ID</td>
<td>1BA7, 1BXU, 5T15</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>38 kDa</td>
</tr>
<tr>
<td class="label">Amino Acids</td>
<td>326</td>
</tr>
<tr>
<td class="label">Subcellular Localization</td>
<td>Nucleus, Cytoplasm</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>ELAV/Hu family</td>
</tr>
<tr>
<td class="label">Brain Expression</td>
<td>Hippocampus, Cortex, Cerebellum</td>
</tr>
<tr>
<td class="label">Diseases</td>
<td>ALS, FTD, AD</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/dementia" style="color:#ef9a9a">Dementia</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a>, <a href="/wiki/neurodegeneration" style="color:#ef9a9a">Neurodegeneration</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">17 edges</a></td>
</tr>
</table>

ELAVL4 Protein — ELAV-Like Protein 4

ELAVL4 Protein

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">ELAV-Like Protein 4</th>
</tr>
<tr> [@elavl2016]
<td class="label">Protein Name</td> [@brain2020]
<td>ELAV-Like Protein 4 (HuD)</td> [@tdp2020]
</tr> [@elavl2020]
<tr>
<td class="label">Gene</td>
<td>[ELAVL4](/genes/elavl4)</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td><a href="https://www.uniprot.org/uniprot/P26378" target="_blank">P26378</a></td>
</tr>
<tr>
<td class="label">PDB ID</td>
<td>1BA7, 1BXU, 5T15</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>38 kDa</td>
</tr>
<tr>
<td class="label">Amino Acids</td>
<td>326</td>
</tr>
<tr>
<td class="label">Subcellular Localization</td>
<td>Nucleus, Cytoplasm</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>ELAV/Hu family</td>
</tr>
<tr>
<td class="label">Brain Expression</td>
<td>Hippocampus, Cortex, Cerebellum</td>
</tr>
<tr>
<td class="label">Diseases</td>
<td>ALS, FTD, AD</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/dementia" style="color:#ef9a9a">Dementia</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a>, <a href="/wiki/neurodegeneration" style="color:#ef9a9a">Neurodegeneration</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">17 edges</a></td>
</tr>
</table>

ELAVL4 Protein — ELAV-Like Protein 4

Introduction

ELAVL4 (ELAV-Like Protein 4), also known as HuD, is a neuron-specific RNA-binding protein encoded by the ELAVL4 gene located on chromosome 1p34.2. It belongs to the ELAV (Embryonic Lethal, Abnormal Vision, Drosophila) family of RNA-binding proteins, which in mammals includes ELAVL1 (HuR), ELAVL2 (HuB), ELAVL3 (HuC), and ELAVL4 (HuD). These proteins are characterized by their ability to bind AU-rich elements (AREs) in the 3' untranslated regions (UTRs) of messenger RNAs (mRNAs), thereby regulating mRNA stability, localization, and translation.

ELAVL4 is primarily expressed in neuronal tissues and plays critical roles in neuronal development, differentiation, synaptic plasticity, and maintenance of neuronal identity. In the context of neurodegenerative diseases, ELAVL4 has been implicated in Amyotrophic Lateral Sclerosis (ALS), Frontotemporal Dementia (FTD), and Alzheimer's Disease (AD). Dysregulation of ELAVL4 function contributes to [TDP-43](/proteins/tdp-43) proteinopathy, a hallmark of ALS/FTD spectrum disorders, and affects synaptic protein expression in AD^[1].

Overview

ELAVL4 is a 326-amino acid protein that contains three highly conserved RNA recognition motifs (RRMs), each consisting of approximately 90 amino acids with the canonical RNP1 (octamer) and RNP2 (hexamer) sequence motifs. The protein localizes to both the nucleus and cytoplasm of [neurons](/entities/neurons), where it performs distinct functions in each compartment. In the nucleus, ELAVL4 participates in alternative splicing regulation, while in the cytoplasm, it controls mRNA stability and translational efficiency^[2].

The ELAVL4 gene (NCBI Gene ID: 19988) is expressed predominantly in the central nervous system, with highest levels in the hippocampus, cerebral cortex, and cerebellum. Expression begins during embryonic development and persists throughout adulthood, reflecting its essential role in neuronal maintenance. Mutations in ELAVL4 have been associated with increased risk of ALS and FTD, highlighting its importance in motor neuron and frontal/temporal lobe biology^[3].

Protein Structure

RNA Recognition Motifs (RRMs)

ELAVL4 contains three highly conserved RRMs arranged in tandem:

RRM1 (aa 17-96)

• Binds to ARE sequences in target mRNAs
• Contains RNP1: K-G-F-V-I-I-R-V and RNP2: I-Y-I-N-P-M-L
• Primary RNA-binding interface
• High affinity for U-rich and A/U-rich sequences

• Contributes to RNA binding specificity
• Cooperates with RRM1 for high-affinity binding
• Contains auxiliary RNA-binding surfaces

• C-terminal RRM involved in protein dimerization
• Binds to longer RNA sequences
• Mediates interactions with other RNA-binding proteins

Structural Studies

Crystal structures of ELAVL4 RRM domains bound to RNA have revealed the molecular basis of RNA recognition. The RRM fold consists of a four-stranded β-sheet flanked by two α-helices, with the RNP motifs located on the β3 and β1 strands, respectively, creating an RNA-binding surface^[4].

Molecular Function

RNA Binding and Regulation

ELAVL4 recognizes and binds to AU-rich elements (AREs) in the 3' UTRs of target mRNAs through its RRM domains. The protein can either stabilize or destabilize bound mRNAs, depending on the context and associated proteins:

mRNA Stabilization:

• ELAVL4 protects mRNAs from deadenylation and decay
• Competes with decay-promoting RNA-binding proteins
• Recruits translation initiation factors

• Facilitates or represses translation initiation
• Regulates localized translation in dendrites
• Couples neuronal activity to protein synthesis

Target mRNAs

Key neuronal mRNAs regulated by ELAVL4 include:

| mRNA Target | Function | Disease Relevance |
|-------------|----------|-------------------|
| [MAPT](/proteins/mapt-protein) (Tau) | Microtubule stability | AD, FTD |
| [APP](/entities/app-protein) | Amyloid precursor protein | AD |
| BDNF | Neurotrophin | Neuronal survival |
| GRIA1/2 | AMPA receptor subunits | Synaptic plasticity |
| SNCA | [α-Synuclein](/proteins/alpha-synuclein) | PD |
| TARDBP | TDP-43 | ALS, FTD |

Nuclear Function: Alternative Splicing

In the nucleus, ELAVL4 influences alternative splicing of neuronal pre-mRNAs. It interacts with components of the spliceosome and modulates the inclusion or exclusion of specific exons. This function is particularly important for generating neuronal isoform diversity^[5].

Brain Expression and Localization

Regional Expression

ELAVL4 is expressed throughout the brain with highest levels in:

• [Hippocampus](/brain-regions/hippocampus): Particularly in CA1-CA3 pyramidal neurons and dentate gyrus granule cells
• Cerebral [Cortex](/brain-regions/cortex): Layer 2-6 pyramidal neurons
• Cerebellum: Purkinje cells and granule cells
• Basal Ganglia: Striatal medium spiny neurons
• Brainstem: Various cranial nerve nuclei
• Spinal Cord: Motor neurons (relevant to ALS)

Subcellular Localization

• Nucleus: Concentrated in nuclear speckles, involved in RNA processing
• Cytoplasm: Diffuse cytoplasmic distribution with enrichment in dendritic compartments
• Synapses: Localized to pre- and post-synaptic compartments
• RNA Granules: Associates with stress granules and neuronal RNA granules

Disease Associations

Amyotrophic Lateral Sclerosis (ALS)

ELAVL4 is increasingly recognized as an important player in ALS pathogenesis:

Mechanisms:

• TDP-43 pathology: ELAVL4 interacts with TDP-43 and influences its aggregation
• RNA dysregulation: Loss of ELAVL4 function leads to aberrant RNA metabolism
• Motor neuron vulnerability: Altered expression of survival-related mRNAs
• Stress granule dynamics: ELAVL4 localizes to stress granules; dysfunction affects granule clearance

• ELAVL4 variants increase ALS risk
• Linkage to 1p34.2 locus in familial ALS
• Interaction with known ALS genes ([C9orf72](/entities/c9orf72), SOD1, FUS, TARDBP)^[7]

Frontotemporal Dementia (FTD)

ELAVL4 dysfunction contributes to FTD through overlapping mechanisms with ALS:

Pathology:

• TDP-43 positive inclusions in affected brain regions
• Dysregulated RNA metabolism in frontal and temporal lobes
• Impaired synaptic protein expression
• Neuronal loss in frontotemporal cortex

• ALS-FTD spectrum disorders
• Behavioral variant FTD (bvFTD)
• Primary progressive aphasia (PPA)

Alzheimer's Disease (AD)

ELAVL4 plays complex roles in AD pathogenesis:

Protective Functions:

• Stabilizes [MAPT](/proteins/tau) mRNA, regulating tau expression
• Modulates APP processing through post-transcriptional regulation
• Protects synaptic mRNAs from decay

• Dysregulated ELAVL4 may contribute to amyloid pathology
• Altered neuronal activity affects ELAVL4 function
• May influence tau phosphorylation and aggregation^[8]

Parkinson's Disease (PD)

Emerging evidence links ELAVL4 to PD:

• Regulates SNCA (α-synuclein) mRNA stability
• Altered expression in PD brain tissue
• May affect dopaminergic neuron survival
• Potential biomarker value

Interaction Network

ELAVL4 interacts with numerous proteins involved in RNA metabolism and neurodegeneration:

RNA-Binding Proteins

• TDP-43 (TARDBP): Direct protein-protein interaction
• FUS: RNA granule formation
• TIA1: Stress granule components
• HNRNPA1/A2B1: Alternative splicing regulation

Translation Machinery

• eIF4A: Translation initiation factor
• PABPC1: Poly(A)-binding protein
• UPF1: Nonsense-mediated decay

Disease Proteins

• TDP-43: ALS/FTD pathology
• α-Synuclein (SNCA): PD
• Tau (MAPT): AD, FTD

Signaling Molecules

• PKC: Phosphorylation affects ELAVL4 localization
• MAPK/ERK: Activity-dependent regulation
• [mTOR](/entities/mtor): Translational control pathways

Therapeutic Implications

Small Molecule Approaches

Gene Therapy Strategies

Biomarker Development

• ELAVL4 levels in cerebrospinal fluid as ALS/FTD biomarker
• Genetic testing for risk variants
• PET ligands for detecting ELAVL4 pathology

Key Publications

External Links

• UniProt: [P26378](https://www.uniprot.org/uniprot/P26378)
• NCBI Gene: [19988](https://www.ncbi.nlm.nih.gov/gene/19988)
• PDB: [1BA7](https://www.rcsb.org/structure/1BA7), [1BXU](https://www.rcsb.org/structure/1BXU)
• Allen Brain Atlas: [ELAVL4 expression](https://human.brain-map.org/)

See Also

• [ELAVL4 Gene](/proteins/elavl4-protein)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [ALS Gene Overview](/diseases/als)
• [FTD Gene Overview](/diseases/frontotemporal-dementia)
• [RNA-Binding Proteins in Neurodegeneration](/mechanisms/rna-metabolism-dysregulation)
• [TDP-43 Proteinopathy](/mechanisms/tdp-43-proteinopathy)

Background

The study of Elavl4 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.

References