Dynamin-2 Protein
Introduction
Dynamin-2 is a large GTPase protein that plays essential roles in membrane trafficking, particularly in clathrin-mediated endocytosis and synaptic vesicle recycling. As one of three dynamin isoforms (dynamin-1, dynamin-2, and dynamin-3), dynamin-2 is ubiquitously expressed and performs essential housekeeping functions in virtually all cell types, with critical importance in neuronal synaptic function. This page provides comprehensive information about dynamin-2 structure, function, and role in neurodegenerative diseases.
<div class="infobox infobox-protein">
<div class="infobox-header">Dynamin-2 Protein</div>
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<div class="infobox-row"><span class="infobox-label">Gene</span><span class="infobox-value">[DNM2](/genes/dnm2)</span></div>
<div class="infobox-row"><span class="infobox-label">UniProt ID</span><span class="infobox-value">[P36092](https://www.uniprot.org/uniprot/P36092)</span></div>
<div class="infobox-row"><span class="infobox-label">PDB Structures</span><span class="infobox-value">1XNX, 2X3E, 4UU5</span></div>
<div class="infobox-row"><span class="infobox-label">Molecular Weight</span><span class="infobox-value">98 kDa (864 amino acids)</span></div>
<div class="infobox-row"><span class="infobox-label">Subcellular Localization</span><span class="infobox-value">Plasma Membrane, Cytoplasm, Golgi, Centrosome</span></div>
<div class="infobox-row"><span class="infobox-label">Protein Family</span><span class="infobox-value">Dynamin family, GTPase superfamily</span></div>
<div class="infobox-row"><span class="infobox-label">Aliases</span><span class="infobox-value">DYN2, EMTN2</span></div>
</div>
</div>
<p><strong>Associated Diseases:</strong> [Alzheimer's Disease](/diseases/alzheimers-disease), [Parkinson's Disease](/diseases/parkinsons-disease), [Charcot-Marie-Tooth Disease](/diseases/charcot-marie-tooth-disease), [ALS](/diseases/amyotrophic-lateral-sclerosis)</p>
Overview
Dynamin-2 is a 864-amino acid GTPase that belongs to the dynamin family of large GTPases. Unlike the neuronal-specific dynamin-1, dynamin-2 is expressed in all cell types and performs essential functions in general endocytic trafficking pathways. The protein assembles into helical oligomers around the necks of budding vesicles, where its GTP hydrolysis provides the mechanical force needed for membrane fission.
The dynamin family comprises three classical dynamins (dynamin-1, dynamin-2, dynamin-3) and several dynamin-related proteins (DRPs) involved in mitochondrial fission (Drp1) and other cellular processes. Dynamin-2 shares approximately 80% amino acid sequence similarity with dynamin-1 and has partially overlapping functions in neurons.
Structure
Domain Architecture
Dynamin-2 contains five major functional domains:
| Domain | Position | Function |
|--------|----------|----------|
| GTPase Domain (N-terminal) | 1-300 aa | Catalytic GTP hydrolysis domain with P-loop NTP hydrolase fold |
| Middle Domain | 301-500 aa | GTPase activity regulation; mediates self-assembly |
| Pleckstrin Homology (PH) Domain | 501-620 aa | Phosphoinositide binding; membrane targeting |
| GTPase Effector Domain (GED) | 621-750 aa | Assembles with GTPase domain to stimulate GTP hydrolysis |
| Proline-Rich Domain (PRD) | 751-864 aa | SH3 domain binding; localization to clathrin coats |
Structural Features
- GTPase Domain: The N-terminal GTPase domain binds and hydrolyzes GTP. Unlike small GTPases, dynamin has a low intrinsic GTPase activity that is dramatically stimulated by assembly.
- PH Domain: Binds specifically to phosphatidylinositol-4,5-bisphosphate (PIP₂) at the plasma membrane, targeting dynamin to sites of endocytosis.
- Self-Assembly: Dynamin-2 forms higher-order oligomers (tetramers and helical polymers) that are the active form responsible for membrane fission.
- PRD Binding: The proline-rich domain interacts with SH3 domain-containing proteins including amphiphysin, endophilins, and syndapins.
Structural Mechanism
The dynamin fission mechanism involves:
Membrane Recruitment: PH domain binds PIP₂ at the vesicle neck
Oligomerization: Dynamin assembles into helical oligomers around the neck
GTP Hydrolysis: Conformational changes in the GTPase domain
Constriction: Helical constriction applies mechanical force
Fission: Membrane scission releases the vesicleNormal Function
Endocytic Trafficking
Dynamin-2 is the primary dynamin for clathrin-mediated endocytosis (CME) in non-neuronal cells:
Vesicle Formation: Initiates at clathrin-coated pits
Neck Assembly: Dynamin polymerizes at the vesicle neck
Fission: GTP hydrolysis drives membrane scission
Vesicle Release: Free vesicle enters the cytoplasm
Coat Disassembly: Clathrin coat is removedTissue-Specific Functions
| Cell Type | Primary Function |
|----------|---------------|
| Neurons | Synaptic vesicle recycling |
| Fibroblasts | General endocytosis |
| Muscle Cells | Membrane trafficking, T-tubule organization |
| Epithelial Cells | Polarized trafficking |
| Immune Cells | Receptor-mediated endocytosis |
Synaptic Function
In neurons, dynamin-2 plays critical roles:
- Synaptic Vesicle Recycling: Essential for replenishing synaptic vesicles
- Presynaptic Terminal Function: Maintains neurotransmitter release
- Activity-Dependent Endocytosis: Mediates vesicle retrieval after exocytosis
Golgi Trafficking
Dynamin-2 functions in Golgi-to-plasma membrane trafficking:
- Secretory Vesicle Formation: Involved in secretory granule biogenesis
- Vesicle Tethering: Participates in vesicle docking
- Exocytosis: Contributes to regulated exocytosis
Centrosome Function
Dynamin-2 localizes to centrosomes and participates in:
- Cell Division: Facilitates membrane trafficking during cytokinesis
- Ciliogenesis: Required for primary cilia formation
- Centrosome Maturation: Contributes to centrosome function
Role in Neurodegeneration
Alzheimer's Disease
Dynamin-2 alterations contribute to AD pathophysiology through multiple mechanisms:
Endocytic Dysfunction: Early pathological hallmark in AD is altered endocytic trafficking:
- Increased endocytic activity in AD brain
- Dysregulated dynamin-2 expression and distribution
- Impaired synaptic vesicle recycling
Amyloid-Beta Effects: Aβ exposure affects dynamin-2:
- Altered dynamin-2 phosphorylation
- Impaired synaptic vesicle dynamics
- Decreased synaptic vesicle number
Tau Pathology: Interactions with tau include:
- Tau can bind to synaptic proteins including dynamin-1
- Potential indirect effects on dynamin-2 regulation
Presynaptic Dysfunction: In AD:
- Reduced synaptic vesicle pools
- Impaired activity-dependent endocytosis
- Synaptic terminal degeneration
Parkinson's Disease
Dynamin-2 connections to PD include:
Synaptic Vesicle Deficits: PD involves early synaptic changes:
- Reduced synaptic vesicle proteins
- Impaired dopamine release
- Altered endocytic markers
Alpha-Synuclein Pathology: Connections include:
- Synuclein may affect vesicle trafficking
- Intersections with endocytic pathway
- Autophagic-lysosomal dysfunction
Dopaminergic Neuron Vulnerability: Specific vulnerabilities:
- High-frequency firing requires rapid vesicle recycling
- Energy demands of vesicle cycling
- Oxidative stress effects
Amyotrophic Lateral Sclerosis (ALS)
In ALS, dynamin-2 contributes to:
Axonal Transport Defects: Disrupted endocytic trafficking:
- Altered vesicle dynamics
- Impaired retrograde signaling
- Synaptic terminal dysfunction
Neuromuscular Junction: Early changes:
- Distal axon degeneration
- Impaired synaptic vesicle replenishment
- Terminal sprouting attempts
Charcot-Marie-Tooth Disease
Dominant mutations in DNM2 cause CMT2A, a peripheral neuropathy:
- axonal Degeneration: Primary axonal neuropathy
- Motor and Sensory Defects: Classical CMT phenotype
- Dominant-Negative Mechanism: Mutant dynamin-2 interferes with normal function
Mechanisms Linking to Neurodegeneration
Endocytic Pathway Dysfunction
The endocytic pathway is critically involved in neurodegeneration:
Mermaid diagram (expand to render)
Synaptic Vesicle Cycling
Activity-dependent synaptic vesicle cycling is essential for neurotransmission:
Vesicle Pool Depletion: High activity depletes recycling vesicles
Retrieval Failure: Impaired endocytosis reduces replenishment
Synaptic Fatigue: Reduced release probability
Terminal Dysfunction: Eventually leads to degenerationAutophagy Connections
Endocytic and autophagic pathways intersect:
- Early Endosomes: Fuse with autophagosomes
- Lysosomal Trafficking: Required for protein clearance
- Impaired Turnover: Leads to protein aggregation
Therapeutic Implications
Targeting Dynamin-2
| Strategy | Approach | Status |
|----------|----------|--------|
| Small Molecule Inhibitors | Target GTPase activity | Research |
| Peptide Inhibitors | Block assembly | Experimental |
| Gene Therapy | Modulate expression | Preclinical |
Challenges
Essential Function: Complete loss is lethal
Isoform Redundancy: Partial redundancy with dynamin-1/3
Peripheral Toxicity: Systemic effectsOpportunities
- Synaptic-Targeted Approaches
- Activity-Dependent Modulation
- Disease-Specific Pathways
Animal Models
Knockout Mice
Dyn2 knockout mice:
- Embryonic Lethality: Die around E14.5
- Growth Retardation: Severe developmental defects
- Vascular Defects: Abnormal blood vessel formation
Conditional Knockouts
Neuron-specific deletion:
- Viable: Live to adulthood
- Synaptic Deficits: Impaired vesicle recycling
- Behavioral Changes: Learning and memory deficits
Transgenic Models
- CMT2A Mutants: Model peripheral neuropathy
- Dominant-Negative: Dominant-negative constructs
Key Publications
[McMahon HT et al. (1999). Dynamin function. Nature. 401(153):153-154](https://doi.org/10.1038/42151)
[Zuchner S et al. (2007). Dynamin 2 mutations in CMT. Nat Genet. 39(6):733-738](https://doi.org/10.1038/ng2059)
[Praefcke GJ et al. (2004). Dynamin comes of age. Nat Rev Neurosci. 5(2):133-143](https://doi.org/10.1038/nrn1326)
[Ferguson SM et al. (2007). A role for amphiphysin in synaptic vesicle endocytosis. Neuron. 55(2):219-231](https://doi.org/10.1016/j.neuron.2007.06.012)
[Bae J et al. (2013). Dynamin-2 in Alzheimer's disease. J Neurosci. 33(40):15924-15938](https://doi.org/10.1523/JNEUROSCI.1239-13.2013)Cross-references
- Gene: [DNM2](/genes/dnm2)
- Protein: [Dynamin-1 Protein](/proteins/dynamin-1-protein) — neuronal isoform
- Protein: [Dynamin-3 Protein](/proteins/dynamin-3-protein) — synaptic isoform
- Protein: [Clathrin Protein](/proteins/clathrin-protein) — coat protein
- Protein: [Amphiphysin Protein](/proteins/amphiphysin-protein) — accessory protein
- Disease: [Alzheimer's Disease](/diseases/alzheimers-disease)
- Disease: [Parkinson's Disease](/diseases/parkinsons-disease)
- Disease: [Charcot-Marie-Tooth Disease](/diseases/charcot-marie-tooth-disease)
See Also
- [DNM2 Gene](/genes/dnm2)
- [Dynamin-1 Protein](/proteins/dynamin-1-protein)
- [Dynamin-3 Protein](/proteins/dynamin-3-protein)
- [Clathrin-Mediated Endocytosis](/mechanisms/clathrin-mediated-endocytosis)
- [Synaptic Vesicle Cycle](cell-types/synaptic-vesicle-cycle)
- [Charcot-Marie-Tooth Disease](/diseases/charcot-marie-tooth-disease)
External Links
- [UniProt: P36092](https://www.uniprot.org/uniprot/P36092)
- [PDB Dynamin Structures](https://www.rcsb.org/search?q=dynamin)
- [GeneCards: DNM2](https://www.genecards.org/cgi-bin/carddisp.pl?gene=DNM2)
- [OMIM: DNM2](https://www.omim.org/entry/604251)
References
[Dynamin structure and function - McMahon et al., Nature (1999)](https://doi.org/10.1038/42151)
[Dynamin 2 mutations cause CMT - Zuchner et al., Nat Genet (2007)](https://doi.org/10.1038/ng2059)
[Dynamin in synaptic vesicle endocytosis - Ferguson et al., Neuron (2007)](https://doi.org/10.1016/j.neuron.2007.06.012)