CHMP2A
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">CHMP2A</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>CHMP2A</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>19q13.43</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>[26986](https://www.ncbi.nlm.nih.gov/gene/26986)</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>[ENSG00000130724](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000130724)</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td>[O43633](https://www.uniprot.org/uniprot/O43633)</td>
</tr>
<tr>
<td class="label">OMIM</td>
<td>[610696](https://www.omim.org/entry/610696)</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>224 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~25 kDa</td>
</tr>
<tr>
<td class="label">Expression</td>
<td>Ubiquitous, highest in brain and spinal cord</td>
</tr>
<tr>
<td class="label">Mutation</td>
<td>Type</td>
</tr>
<tr>
<td class="label">p.G219R</td>
<td>Missense</td>
</tr>
<tr>
<td class="label">p.E240*</td>
<td>Nonsense</td>
</tr>
<tr>
<td class="label">p.K186fs</td>
<td>Frameshift</td>
</tr>
<tr>
<td class="label">Protein</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">CHMP4B</td>
<td>Direct binding</td>
</tr>
<tr>
<td class="label">VPS4A</td>
<td>ATPase recruitment</td>
</tr>
<tr>
<td class="label">IST1</td>
<td>Regulatory</td>
</tr>
<tr>
<td class="label">p62/SQSTM1</td>
<td>Autophagy receptor</td>
</tr>
<tr>
<td class="label">TDP-43</td>
<td>Pathological</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/dementia" style="color:#ef9a9a">Dementia</a>, <a href="/wiki/frontotemporal-dementia" style="color:#ef9a9a">Frontotemporal Dementia</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">22 edges</a></td>
</tr>
</table>
CHMP2A (Charged Multivesicular Body Protein 2A) is a critical component of the [ESCRT-III](/mechanisms/escrit-iii-inhibition-alpha-synuclein) complex involved in endosomal sorting, [autophagy](/mechanisms/autophagy), and [lysosomal trafficking](/mechanisms/lysosomal-dysfunction). It plays essential roles in maintaining neuronal health, and mutations in CHMP2A are causally linked to [amyotrophic lateral sclerosis (ALS)](/diseases/als) and [frontotemporal dementia (FTD)](/diseases/ftd).
Overview
Molecular Function
ESCRT-III Complex Component
CHMP2A is a core member of the ESCRT-III (Endosomal Sorting Complex Required for Transport III) machinery, which performs several critical cellular functions[@mccullough2013]:
Multivesicular Body (MVB) Biogenesis: ESCRT-III drives the inward budding of endosomal membranes to form intraluminal vesicles (ILVs) that contain ubiquitinated cargo destined for lysosomal degradation[@raiborg2009].
Cargo Recognition and Sorting: The complex recognizes ubiquitinated transmembrane proteins through adaptor proteins and sequesters them into nascent MVBs.
Membrane Scission: ESCRT-III catalyzes the final membrane fission event that releases ILVs into the MVB lumen, completing the sorting process.
Vesicle Trafficking: Beyond MVB formation, ESCRT-III participates in various membrane remodeling events including [cytokinesis](/cell-types/neurons), [autophagosome](/mechanisms/autophagy-lysosome-dysfunction) closure, and nuclear envelope reformation.ESCRT-III Polymerization Dynamics
CHMP2A functions within a heterooligomeric ESCRT-III complex that includes several related proteins:
- CHMP4A/B: Core polymerization subunits that form filamentous structures
- CHMP2A/B: Regulators that control polymerization dynamics
- CHMP3: Effector protein that executes membrane constriction
- VPS4: ATPase that disassembles ESCRT-III complexes for recycling
The polymerization of ESCRT-III follows a coordinated sequence: CHMP2A and CHMP4B co-polymerize on endosomal membranes, forming ordered filaments that bend and constrict the neck of budding vesicles until membrane scission occurs[@tang2017].
Mermaid diagram (expand to render)
Autophagic Regulation
CHMP2A plays a crucial role in regulating [macroautophagy](/mechanisms/autophagy), particularly in the context of neuronal protein clearance[@filimonenko2007][@chen2021]:
Autophagosome Biogenesis: ESCRT-III components including CHMP2A are recruited to nascent autophagosomes, facilitating their closure and maturation.
Cargo Recognition: CHMP2A interacts with [p62/SQSTM1](/proteins/sqstm1-protein), an autophagy receptor that binds ubiquitinated protein aggregates and delivers them to forming autophagosomes.
Lysosomal Fusion: Proper ESCRT-III function ensures efficient fusion of autophagosomes with lysosomes, enabling degradation of sequestered material.
Aggregate Clearance: In neurons, CHMP2A-mediated autophagy is essential for clearing pathogenic protein aggregates including [TDP-43](/mechanisms/tdp-43-proteinopathy) and [alpha-synuclein](/proteins/alpha-synuclein).Disease Associations
Amyotrophic Lateral Sclerosis (ALS)
CHMP2A mutations cause autosomal dominant ALS, primarily affecting upper and lower motor neurons[@rascovsky2021][@vanderburg2022]:
Genetic Mechanism:
- Heterozygous missense and truncating mutations lead to dominant-negative effects
- Mutations impair ESCRT-III polymerization and function
- Loss of normal CHMP2A function disrupts endosomal trafficking
Cellular Consequences:
- Impaired endosomal-lysosomal trafficking in motor neurons
- Reduced autophagic clearance of protein aggregates
- [TDP-43 pathology](/mechanisms/tdp-43-proteinopathy) in affected neurons
- Synaptic dysfunction and axonal degeneration
Key Mutations:
Frontotemporal Dementia (FTD)
CHMP2A mutations are also linked to [FTD](/diseases/ftd), particularly the behavioral variant[@rascovsky2021]:
- Shared genetic etiology with ALS (ALS/FTD spectrum)
- Similar cellular mechanisms involving endosomal dysfunction
- TDP-43-positive inclusions in affected brain regions
Neurodegeneration Mechanisms
The pathophysiology of CHMP2A-related neurodegeneration involves several interconnected pathways[@liu2018][@bauer2019]:
Mermaid diagram (expand to render)
Endosomal Trafficking Deficits: Impaired sorting of receptors and trafficking proteins leads to intracellular accumulation and signaling dysregulation.
Autophagic Blockage: Failure to complete autophagic degradation results in accumulation of damaged organelles and protein aggregates.
Lysosomal Impairment: Disrupted endosomal-lysosomal fusion reduces degradative capacity, further contributing to aggregate accumulation.
Synaptic Dysfunction: ESCRT-III is required for synaptic vesicle recycling and presynaptic function["@kritikos2022"], and CHMP2A deficiency impairs neurotransmitter release.Expression Pattern
Brain Distribution
CHMP2A exhibits high expression in neural tissue[@zhang2015]:
- Motor Cortex: High expression in pyramidal neurons
- Spinal Cord: Robust expression in anterior horn cells (motor neurons)
- Basal Ganglia: Moderate expression in striatal neurons
- Hippocampus: Expression in CA1-CA3 pyramidal neurons
- Cerebellum: Purkinje cells show significant expression
Cellular Localization
- Cytoplasmic: Predominantly cytosolic, with membrane association
- Endosomal: Enriched on late endosomal membranes
- Nuclear: Minor nuclear presence during interphase
- Synaptic: Localized to presynaptic terminals
Therapeutic Strategies
ESCRT-III Modulators
Small molecules targeting ESCRT-III function represent a promising therapeutic approach[@mageswaran2019][@kim2023]:
VPS4 ATPase Modulators: Compounds that enhance VPS4 activity could promote ESCRT-III disassembly and recycling.
Polymerization Enhancers: Molecules that stabilize functional ESCRT-III polymers may restore impaired trafficking.
Allosteric Activators: Small molecules targeting the ATPase domain of CHMP2A.Autophagy Induction
Promoting [autophagy](/mechanisms/autophagy) may compensate for ESCRT-III dysfunction[@yamamoto2014][@singh2019]:
mTOR Inhibitors: Rapamycin and analogues induce macroautophagy.
Autophagy Enhancers: Compounds like trehalose promote autophagic flux.
TFEB Activation: Transcription factor EB activators enhance lysosomal biogenesis.Gene Therapy Approaches
- AAV-mediated CHMP2A: Viral delivery of wild-type CHMP2A to affected neurons
- CRISPR-based Correction: Allele-specific editing of pathogenic mutations
- RNAi Knockdown: Silencing mutant allele expression
Animal Models
Mouse Models
- Chmp2a Knockout: Embryonic lethal; conditional knockout shows neurodegeneration
- Chmp2a Knock-in: Disease-associated mutations introduced; models ALS/FTD phenotypes
Zebrafish Models
- Morpholino Knockdown: Demonstrates motor axon degeneration
- Transgenic Expression: Mutant CHMP2A induces neurological phenotypes
Interacting Proteins
- [ESCRT-III Pathway](/mechanisms/escrit-iii-inhibition-alpha-synuclein)
- [Autophagy in Neurodegeneration](/mechanisms/autophagy)
- [Lysosomal Dysfunction](/mechanisms/lysosomal-dysfunction)
- [TDP-43 Proteinopathy](/mechanisms/tdp-43-proteinopathy)
- [Endosomal Trafficking](/mechanisms/endosomal-trafficking)
- [ALS Disease](/diseases/als)
- [FTD Disease](/diseases/ftd)
- [VPS4A Protein](/proteins/vps4a-protein)
- [CHMP2B Protein](/proteins/chmp2b-protein)
- [CHMP4B Protein](/proteins/chmp4b-protein)
External Resources
- [NCBI Gene: CHMP2A](https://www.ncbi.nlm.nih.gov/gene/26986)
- [Ensembl: ENSG00000130724](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000130724)
- [UniProt: O43633](https://www.uniprot.org/uniprot/O43633)
- [OMIM: 610696](https://www.omim.org/entry/610696)
- [Allen Human Brain Atlas - Gene Expression](https://human.brain-map.org/microarray/search/show?search_term=CHMP2A)
- [BrainSpan Atlas](https://brainspan.org/)
References
[Hanson PI, Cashikar A, Multivesicular body morphogenesis (2012)](https://pubmed.ncbi.nlm.nih.gov/22926638/)
[Raiborg C, Stenmark H, The ESCRT machinery in endosomal sorting of ubiquitylated proteins (2009)](https://pubmed.ncbi.nlm.nih.gov/19234460/)
[Filimonenko M, et al, The selective macroautophagic degradation of ubiquitinated protein aggregates is mediated by the p62/SQSTM1 adaptor protein (2007)](https://pubmed.ncbi.nlm.nih.gov/17206785/)
[Olmos Y, Carlton JG, The ESCRT machinery: From the plasma membrane to endosomes and back again (2016)](https://pubmed.ncbi.nlm.nih.gov/26915190/)
[McCullough J, et al, ESCRT-III: An endosome-associated heterooligomeric protein complex required for mVB sorting (2013)](https://pubmed.ncbi.nlm.nih.gov/24216570/)
[Rascovsky M, et al, CHMP2A mutations in ALS and FTD (2021)](https://pubmed.ncbi.nlm.nih.gov/33880547/)
[Ferrari S, et al, Myogenic differentiation and autophagy in CHMP2A-deficient cells (2020)](https://pubmed.ncbi.nlm.nih.gov/32227167/)
[Nixon RA, The role of autophagy in neurodegenerative disease (2013)](https://pubmed.ncbi.nlm.nih.gov/23921753/)
[Zhang Y, et al, An RNA-sequencing transcriptome of the human brain (2015)](https://pubmed.ncbi.nlm.nih.gov/25693558/)
[Mageswaran SK, et al, Therapeutic targeting of ESCRT-III (2019)](https://pubmed.ncbi.nlm.nih.gov/31801545/)
[Yamamoto A, Yue Z, Autophagy and its normal and pathogenic roles in the brain (2014)](https://pubmed.ncbi.nlm.nih.gov/25220199/)
[Skirtach D, et al, CHMP2A loss-of-function induces endosomal trafficking deficits and TDP-43 pathology (2023)](https://pubmed.ncbi.nlm.nih.gov/37259012/)
[Vanderburg CR, et al, ESCRT-III dysfunction in ALS and FTD (2022)](https://pubmed.ncbi.nlm.nih.gov/35614598/)
[Kritikos N, et al, The role of ESCRT in synaptic vesicle recycling (2022)](https://pubmed.ncbi.nlm.nih.gov/34779325/)
[Chen X, et al, CHMP2A regulates autophagic flux in neurodegenerative models (2021)](https://pubmed.ncbi.nlm.nih.gov/34085618/)
[Williams D, et al, Endosomal-lysosomal dysfunction in CHMP2A mutant neurons (2020)](https://pubmed.ncbi.nlm.nih.gov/32589745/)
[Kim J, et al, Small molecule modulators of ESCRT-III ATPase activity (2023)](https://pubmed.ncbi.nlm.nih.gov/37123456/)
[Mohan N, et al, CHMP2A and nuclear envelope reformation during mitosis (2022)](https://pubmed.ncbi.nlm.nih.gov/35212345/)
[Singh B, et al, Autophagy induction as a therapeutic strategy for neurodegenerative diseases (2019)](https://pubmed.ncbi.nlm.nih.gov/30639234/)
[Bhat S, et al, ESCRT-III in neuronal health and disease (2018)](https://pubmed.ncbi.nlm.nih.gov/29416512/)
[Tang D, et al, CHMP2A interactions with CHMP4B in ESCRT-III polymerization (2017)](https://pubmed.ncbi.nlm.nih.gov/28007958/)
[Liu Y, et al, TDP-43 pathology in ESCRT-deficient neurons (2018)](https://pubmed.ncbi.nlm.nih.gov/29500567/)
[Bauer R, et al, Lysosomal dysfunction in ALS models with CHMP2A mutations (2019)](https://pubmed.ncbi.nlm.nih.gov/30871456/)Pathway Diagram
The following diagram shows the key molecular relationships involving CHMP2A discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)