CYFIP2

CYFIP2

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">CYFIP2</th>
</tr>
<tr>
<td class="label">Gene</td>
<td>CYFIP2</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/Q9Y2D89" target="_blank">Q9Y2D89</a></td>
</tr>
<tr>
<td class="label">PDB</td>
<td>6V0Z, 7AKB</td>
</tr>
<tr>
<td class="label">Mol. Weight</td>
<td>125 kDa</td>
</tr>
<tr>
<td class="label">Localization</td>
<td>Cytoplasm, synapse, lamellipodia</td>
</tr>
<tr>
<td class="label">Family</td>
<td>FMRP interacting protein family, WASF3 complex</td>
</tr>
<tr>
<td class="label">Diseases</td>
<td>Intellectual Disability, Neurodevelopmental Disorders, ALS, Autism Spectrum Disorder</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

CYFIP2 — Cytoplasmic FMRP-Interacting Protein 2

Overview

CYFIP2 (Cytoplasmic FMRP-Interacting Protein 2) is a 125 kDa scaffold protein that plays critical roles in synaptic function, actin cytoskeleton regulation, and neuronal development. Encoded by the CYFIP2 gene, this protein is a member of the FMRP-interacting protein family and serves as a key regulator of the WAVE complex that controls actin polymerization[@uniprot].

CYFIP2

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">CYFIP2</th>
</tr>
<tr>
<td class="label">Gene</td>
<td>CYFIP2</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/Q9Y2D89" target="_blank">Q9Y2D89</a></td>
</tr>
<tr>
<td class="label">PDB</td>
<td>6V0Z, 7AKB</td>
</tr>
<tr>
<td class="label">Mol. Weight</td>
<td>125 kDa</td>
</tr>
<tr>
<td class="label">Localization</td>
<td>Cytoplasm, synapse, lamellipodia</td>
</tr>
<tr>
<td class="label">Family</td>
<td>FMRP interacting protein family, WASF3 complex</td>
</tr>
<tr>
<td class="label">Diseases</td>
<td>Intellectual Disability, Neurodevelopmental Disorders, ALS, Autism Spectrum Disorder</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

CYFIP2 — Cytoplasmic FMRP-Interacting Protein 2

Overview

CYFIP2 (Cytoplasmic FMRP-Interacting Protein 2) is a 125 kDa scaffold protein that plays critical roles in synaptic function, actin cytoskeleton regulation, and neuronal development. Encoded by the CYFIP2 gene, this protein is a member of the FMRP-interacting protein family and serves as a key regulator of the WAVE complex that controls actin polymerization[@uniprot].

CYFIP2 is highly expressed in the brain, particularly in hippocampal neurons and cortical pyramidal cells. It interacts directly with FMRP (Fragile X Mental Retardation Protein) and regulates synaptic translation, morphology, and plasticity. Dominant de novo mutations in CYFIP2 cause a neurodevelopmental disorder characterized by intellectual disability, seizures, and autistic features[@soudake2019][@deboer2019].

Domain Architecture

CYFIP2 contains several functional domains that mediate protein-protein interactions:

N-Terminal Region (1-200 aa)

• HEAT repeats: Mediate interaction with FMRP and other RNA-binding proteins
• Basic region: Potential nuclear localization signal

Central Region (200-500 aa)

• SCAAR region: Involved in actin binding and regulation
• VCA domain: Binds to the WAVE complex (WAVE1, NAP1, ABI1)

C-Terminal Region (500-700 aa)

• coiled-coil domains: Mediate dimerization and complex formation
• Proline-rich region: Binds to SH3 domain-containing proteins

Normal Function in the Nervous System

Synaptic Regulation

CYFIP2 is enriched at synapses where it regulates[@abramian2015]:

• Synaptic translation: Interacts with FMRP to control local protein synthesis at synapses
• Synaptic morphology: Regulates dendritic spine shape and density
• Long-term potentiation (LTP): Required for proper LTP induction and maintenance
• Synaptic plasticity: Modulates both excitatory and inhibitory synaptic transmission

Actin Cytoskeleton Regulation

Through the WAVE complex, CYFIP2 controls[@marson2018]:

• Lamellipodia formation: Regulates actin polymerization at the leading edge of neurons
• Dendritic spine architecture: Controls spine head morphology
• Axonal guidance: Participates in growth cone dynamics
• Synaptic vesicle trafficking: Links actin dynamics to vesicle cycling

RNA Granule Transport

CYFIPIP2 is recruited to RNA granules containing[@zuniga2019]:

• FMRP-bound mRNAs
• Translational machinery
• Transport proteins (e.g., kinesins)

Role in Neurodegenerative Disease

Amyotrophic Lateral Sclerosis (ALS)

CYFIP2 has been implicated in ALS through several mechanisms:

• TDP-43 pathology: CYFIP2 interacts with stress granule proteins that are disrupted in ALS
• FMRP dysregulation: Loss of FMRP-CYFIP2 interaction may contribute to synaptic dysfunction
• WAVE complex disruption: Altered actin regulation affects neuromuscular junction stability
• Motor neuron survival: CYFIP2 expression is reduced in spinal motor neurons of ALS patients

Intellectual Disability and Neurodevelopmental Disorders

Dominant mutations in CYFIP2 cause a distinct neurodevelopmental syndrome characterized by[@deboer2019][@soudake2019]:

• Severe intellectual disability (IQ typically <50)
• Seizures (in ~70% of patients)
• Autistic features and social communication deficits
• Microcephaly or sometimes macrocephaly
• Hypotonia in infancy
• Distinctive facial features

Autism Spectrum Disorder

CYFIP2 is considered an autism risk gene due to:

• FMRP interaction: Shared pathway with Fragile X syndrome
• Synaptic protein synthesis: Disrupted local translation affects synapse formation
• Actin regulation: Altered spine morphology observed in mouse models

Interacting Partners

| Protein | Interaction Type | Functional Significance |
|---------|-----------------|------------------------|
| FMRP | Direct binding | Synaptic translation regulation |
| FMR1 | Indirect | Shared signaling pathway |
| WAVE1 | Complex | Actin polymerization |
| NAP1 | Complex | WAVE complex assembly |
| ABI1 | Complex | WAVE complex, Rac signaling |
| RACK1 | Direct binding | PKC signaling scaffold |
| eIF4G | Direct binding | Translation initiation |

Therapeutic Targeting Landscape

Therapeutic Potential

CYFIP2 represents a potential therapeutic target for:

• Neurodevelopmental disorders: Enhancing CYFIP2 function may improve synaptic function
• ALS: Restoring WAVE complex function and actin regulation
• Fragile X syndrome: Shared therapeutic pathways with CYFIP2 modulation

Challenges

• CYFIP2 dosage is critical — both loss and gain of function cause disease
• Blood-brain barrier penetration required for CNS-targeting approaches
• Dominant-negative mutations are particularly challenging to drug

Current Approaches

Biomarker Potential

CYFIP2 expression in patient-derived cells may serve as:

• A biomarker for neurodevelopmental disease severity
• A pharmacodynamic marker for therapeutic efficacy
• A tool for patient stratification

Practical Interpretation for NeuroWiki Pages

When CYFIP2 is referenced in disease pages:

• Evidence level: Strong for neurodevelopmental disorders; emerging for ALS
• Mechanistic plausibility: High — direct FMRP interaction and actin regulation are well-established
• Therapeutic relevance: Emerging target but not yet clinically validated

See Also

• [FMRP Protein](/proteins/fmrp-protein)
• [WAVE Complex](/mechanisms/wave-complex)
• [Synaptic Plasticity](/mechanisms/synaptic-plasticity)
• [Actin Cytoskeleton](/mechanisms/actin-cytoskeleton)
• [Intellectual Disability](/diseases/intellectual-disability)
• [Autism Spectrum Disorder](/diseases/autism-spectrum-disorder)
• [Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)

External Links

• UniProt: [CYFIP2 (Q9Y2D89)](https://www.uniprot.org/uniprot/Q9Y2D89)
• AlphaFold: [CYFIP2 Structure](https://alphafold.ebi.ac.uk/entry/Q9Y2D89)
• RCSB PDB: [6V0Z](https://www.rcsb.org/structure/6V0Z), [7AKB](https://www.rcsb.org/structure/7AKB)
• NCBI Gene: [CYFIP2 (9777)](https://www.ncbi.nlm.nih.gov/gene/9777)

References