Neurofilament Medium Chain (NEFM) Protein

Neurofilament Medium Chain (NEFM) Protein

<div class="infobox infobox-protein">
<div class="infobox-header">Neurofilament Medium Chain (NEFM)</div>

Overview

Neurofilament Medium Chain is a protein encoded by the [CDK5](/genes/cdk5) gene. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target.

<table>
<tr><th>Gene</th><td>[NEFM](/genes/nefm)</td></tr>
<tr><th>UniProt ID</th><td>[P12036](https://www.uniprot.org/uniprot/P12036)</td></tr>
<tr><th>PDB Structures</th><td>1IDU, 2N3P, 4IPW</td></tr>
<tr><th>Molecular Weight</th><td>102,476 Da</td></tr>
<tr><th>Subcellular Localization</th><td>Cytoplasm, Neuronal axons</td></tr>
<tr><th>Protein Family</th><td>Intermediate filament family</td></tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
</div>

Structure

The Neurofilament Medium Chain (NEFM) is a type IV intermediate filament protein expressed primarily in large myelinated axons. NEFM forms heteropolymers with [neurofilament light](/biomarkers/neurofilament-light-chain-nfl) chain (NEFL) and heavy chain (NEFH), creating the neurofilament triplet that provides structural support and regulates axonal caliber.

The protein contains:

• N-terminal head domain: phosphorylation-regulated
• Central alpha-helical rod domain: 310 residues, forms coiled-coil
• C-terminal tail domain: elongated, heavily phosphorylated, projects outward from the filament core

Neurofilament Medium Chain (NEFM) Protein

<div class="infobox infobox-protein">
<div class="infobox-header">Neurofilament Medium Chain (NEFM)</div>

Overview

Neurofilament Medium Chain is a protein encoded by the [CDK5](/genes/cdk5) gene. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target.

<table>
<tr><th>Gene</th><td>[NEFM](/genes/nefm)</td></tr>
<tr><th>UniProt ID</th><td>[P12036](https://www.uniprot.org/uniprot/P12036)</td></tr>
<tr><th>PDB Structures</th><td>1IDU, 2N3P, 4IPW</td></tr>
<tr><th>Molecular Weight</th><td>102,476 Da</td></tr>
<tr><th>Subcellular Localization</th><td>Cytoplasm, Neuronal axons</td></tr>
<tr><th>Protein Family</th><td>Intermediate filament family</td></tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
</div>

Structure

The Neurofilament Medium Chain (NEFM) is a type IV intermediate filament protein expressed primarily in large myelinated axons. NEFM forms heteropolymers with [neurofilament light](/biomarkers/neurofilament-light-chain-nfl) chain (NEFL) and heavy chain (NEFH), creating the neurofilament triplet that provides structural support and regulates axonal caliber.

The protein contains:

• N-terminal head domain: phosphorylation-regulated
• Central alpha-helical rod domain: 310 residues, forms coiled-coil
• C-terminal tail domain: elongated, heavily phosphorylated, projects outward from the filament core

Normal Function in the Nervous System

NEFM plays critical roles in the nervous system:

NEFM expression increases during development and is maintained in adult neurons. It is essential for maintaining axonal integrity and proper nerve conduction.

Role in Neurodegeneration

Dysregulation of NEFM is implicated in several neurodegenerative diseases:

Alzheimer's Disease (AD)

• NEFM accumulation in NFTs correlates with disease progression
• Hyperphosphorylation leads to aggregation similar to [tau](/proteins/tau)
• CSF NEFM levels are elevated in AD patients and serve as a biomarker

Parkinson's Disease (PD)

• NEFM pathology observed in Lewy bodies
• Axonal degeneration precedes cell body loss
• NEFM fragments detected in PD CSF

Amyotrophic Lateral Sclerosis (ALS)

• NEFM aggregation in motor neurons
• Mutations in NEFM (rare) cause Charcot-Marie-Tooth disease
• Dysregulated phosphorylation in sporadic ALS

Multiple System Atrophy (MSA)

• NEFM in glial cytoplasmic inclusions
• Oligodendrocyte dysfunction affects axonal transport

Biomarker Potential

• CSF NEFM: FDA-approved biomarker for traumatic brain injury
• Blood NEFM: Emerging biomarker for AD, PD, and ALS progression
• Phosphorylated NEFM (pNfH) more specific for neurodegeneration

Therapeutic Targeting

Current therapeutic approaches targeting neurofilaments:

Drug Development

• No direct NEFM-targeted drugs approved yet
• Neurofilament levels used as outcome measures in clinical trials for AD, ALS, and PD

Key Publications

Cross-References

• [NEFL Gene](/genes/nefl)
• [NEFH Protein](/proteins/nefh-protein)
• [Intermediate Filaments in Neurodegeneration](/mechanisms/intermediate-filament-disorders)
• [Biomarkers in Alzheimer's Disease](/clinical-trials/alzheimers-biomarkers)
• [Axonal Transport in Neurodegeneration](/mechanisms/axonal-transport-disorders)

See Also

• CDK5 Gene
• Intermediate Filaments in Neurodegeneration
• Axonal Transport in Neurodegeneration

External Links

• [GeneCards: CDK5](https://www.genecards.org/cgi-bin/carddisp.pl?gene=CDK5)

References