HNRNPA2B1 - Heterogeneous Nuclear Ribonucleoprotein A2/B1
Pathway Diagram
Mermaid diagram (expand to render)
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">HNRNP A2B1</th>
</tr>
<tr> [@liu2022]
<td class="label">Gene Symbol</td> [@martinezcontreras2003]
<td>HNRNPA2B1</td> [@shenkman2020]
</tr> [@glinka2020]
<tr> [@kim2021]
<td class="label">Full Name</td> [@alarcon2015]
<td>Heterogeneous Nuclear Ribonucleoprotein A2/B1</td> [@liu2019]
</tr> [@benatar2020]
<tr>
<td class="label">Chromosomal Location</td>
<td>7p15.2</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>3181</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000122566</td>
</tr>
<tr>
<td class="label">OMIM ID</td>
<td>600124</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P22626</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td>ALS, FTD, Multisystem Proteinopathy</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>HnRNP A/B family</td>
</tr>
</table>
HNRNPA2B1 (Heterogeneous Nuclear Ribonucleoprotein A2/B1)
Introduction
Hnrnpa2B1 Heterogeneous Nuclear Ribonucleoprotein A2 B1 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Overview
HNRNPA2B1 encodes a member of the heterogeneous nuclear ribonucleoprotein family with essential roles in RNA processing, stress granule formation, and RNA localization[@beyer1977]. HNRNPA2B1 is one of the most abundant nuclear
RNA-binding proteins and plays critical roles in alternative splicing, mRNA stability, and translational regulation[@mayeda1992]. Like HNRNPA1, pathogenic mutations in HNRNPA2B1
cause familial ALS and multisystem proteinopathy (MSP), demonstrating the critical importance of hnRNP proteins in motor neuron survival[@kim2013].
The protein contains two RNA recognition motifs (RRMs) and a glycine-rich low-complexity domain that undergoes liquid-liquid phase separation, enabling stress granule formation and
pathological aggregation in neurodegenerative disease[@molliex2015]. HNRNPA2B1 is also recognized as an N6-methyladenosine (m6A) reader, participating in post-transcriptional RNA regulation[@liu2022].
Function
RNA Processing
HNRNPA2B1 participates in multiple aspects of RNA metabolism:
Alternative splicing: Regulation of splice site selection through binding to pre-mRNA[@martinezcontreras2003]
mRNA stability: Binding to AU-rich elements in target mRNAs to regulate degradation[@shenkman2020]
RNA transport: Localizing specific mRNAs to subcellular compartments including neuronal processes[@glinka2020]
Translation: Modulating translational efficiency through interaction with translation initiation factors[@kim2021]
miRNA processing: Involvement in microRNA biogenesis[@alarcon2015]Stress Granules
The glycine-rich low-complexity domain enables HNRNPA2B1 to undergo liquid-liquid phase separation (LLPS):
- Formation of stress granules under cellular stress conditions
- Dynamic exchange between membraneless organelles and cytoplasmic pool
- Pathological aggregation when prion-like domains mutate
- Sequestration of translation machinery and signaling proteins
N6-methyladenosine (m6A) Reading
HNRNPA2B1 functions as an m6A reader:
- Recognizes m6A-modified mRNA transcripts
- Regulates RNA splicing and nuclear export
- Influences mRNA stability and translation
- Dysregulation affects neuronal function and survival
Protein Structure
Domain Organization
HNRNPA2B1 contains several functional domains:
- RNA Recognition Motif 1 (RRM1): N-terminal RRM that binds single-stranded RNA
- **RNA Recognition Motif 2 (RRM2): C-terminal RRM for RNA binding specificity
- Glycine-rich low-complexity domain: Prion-like domain enabling phase separation
- Nuclear localization signal (NLS): Targets protein to the nucleus
Post-translational Modifications
The protein undergoes various modifications:
- Phosphorylation: Affects localization and RNA binding
- Methylation: Influences protein-protein interactions
- Sumoylation: Regulates stress granule dynamics
Expression Patterns
Tissue Distribution
HNRNPA2B1 is ubiquitously expressed with high levels in:
- Brain (particularly [cortex](/brain-regions/cortex), [hippocampus](/brain-regions/hippocampus), and motor neurons)
- Skeletal muscle
- Heart
- Lung
- Testis
Cellular Localization
- Predominantly nuclear (speckles and nucleoplasm)
- Cytoplasmic localization during active RNA transport
- Stress granule localization under cellular stress
Disease Associations
Amyotrophic Lateral Sclerosis (ALS)
HNRNPA2B1 mutations cause familial ALS with typical clinical features:
- Progressive muscle weakness and atrophy
- Fasciculations and muscle cramps
- Bulbar involvement (dysarthria, dysphagia)
- Respiratory involvement in later stages
- Typical age of onset in 40s-60s[@kim2013]
The D262V mutation in the prion-like domain was the first identified pathogenic variant causing ALS[@liu2019].
Multisystem Proteinopathy (MSP)
The HNRNPA2B1-related disorder presents with a triad of conditions:
- Inclusion body myopathy: Progressive muscle weakness, typically beginning in adulthood
- Paget disease of bone: Increased bone turnover with focal lesions
- Frontotemporal Dementia: Cognitive and behavioral changes
This rare autosomal dominant disorder demonstrates the link between muscle, bone, and neuronal pathology[@benatar2020].
Frontotemporal Dementia (FTD)
While primarily associated with ALS, HNRNPA2B1 mutations can cause FTD without Motor Neuron Disease:
- Behavioral variant FTD (bvFTD)
- Language variant (primary progressive aphasia)
- Progressive Supranuclear Palsy phenotype
Pathogenesis
Prion-like Propagation
HNRNPA2B1 aggregates in a prion-like manner:
Mutant protein misfolds and forms oligomers
Oligomers seed aggregation of wild-type protein
Aggregates spread through neural networks
Progressive loss of neuronal functionStress Granule Dysregulation
Pathogenic mutations disrupt stress granule dynamics:
- Excessive phase separation
- Impaired disassembly of stress granules
- Sequestration of essential cellular proteins
- Disruption of RNA metabolism
ALS-associated mutations cause:
- Altered splicing of survival motor neuron (SMN) transcripts
- Dysregulated translation of neuronal proteins
- Impaired RNA transport to synaptic terminals
Animal Models
Drosophila Models
- Knock-in and overexpression models recapitulate key features
- Motor dysfunction and reduced lifespan observed
- Stress granule accumulation in [neurons](/entities/neurons)
Mouse Models
- Transgenic mice with mutant HNRNPA2B1 show:
- Motor neuron degeneration
- Muscle denervation
- Gliosis in spinal cord
- Behavioral deficits
Therapeutic Approaches
Gene Therapy Strategies
- Antisense oligonucleotides (ASOs): Reduce mutant allele expression
- CRISPR-based approaches: Correct mutations or allele-specific silencing
- AAV delivery: Target CNS motor neurons
Small Molecule Approaches
- Phase separation modulators: Normalize LLPS dynamics
- Protein aggregation inhibitors: Prevent toxic oligomer formation
- RNA metabolism modulators: Restore proper RNA processing
Biomarkers
- Elevated HNRNPA2B1 in cerebrospinal fluid of ALS patients
- Potential for disease progression monitoring
- Utility in clinical trial enrollment
See Also
- [Genes Index](/genes)
- [Proteins Index](/proteins)
- [ALS](/diseases/als)
- [FTD](/diseases/ftd)
- [HNRNPA1](/proteins/HNRNPA1)
- [Stress Granules](/mechanisms/stress-granules)
- [RNA Metabolism](/mechanisms/rna-metabolism)
External Links
- NCBI Gene: [HNRNPA2B1](https://www.ncbi.nlm.nih.gov/gene/3181)
- Ensembl: [HNRNPA2B1](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000122566)
- UniProt: [P22626](https://www.uniprot.org/uniprotkb/P22626)
- OMIM: [HNRNPA2B1](https://www.omim.org/entry/600124)
- ALS Genetics: [ALSGene](https://alsgene.org/)
Brain Atlas Resources
- [Allen Brain Atlas](https://brain-map.org)
- [Allen Human Brain Atlas: HNRNPA2B1 search](https://human.brain-map.org/microarray/search/show?search_term=HNRNPA2B1)
- [Allen Mouse Brain Atlas: HNRNPA2B1 search](https://mouse.brain-map.org/search/index.html?query=HNRNPA2B1)
- [Allen Cell Type Atlas](https://portal.brain-map.org/atlases-and-data/rnaseq)
- [BrainSpan Developmental Transcriptome](https://www.brainspan.org)
Background
The study of Hnrnpa2B1 Heterogeneous Nuclear Ribonucleoprotein A2 B1 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
[Beyer AL, Christensen ME, Walker BW, LeStourgeon WM, "Identification and characterization of the packaging proteins of core 40S hnRNP particles." Cell (1977)](https://doi.org/10.1016/0092-8674(77)
[Mayeda A, Krainer AR, "Regulation of alternative pre-mRNA splicing by hnRNP A1/A2B1." Cell (1992)](https://doi.org/10.1016/0092-8674(92)
[Kim HJ, Kim NC, Wang YD, et al, "Mutations in prion-like domains in hnRNPA1 and hnRNPA2B1 cause amyotrophic lateral sclerosis and Frontotemporal Dementia." Nature (2013)](https://doi.org/10.1038/nature11922)
[Molliex A, Taylor J, Fare CM, et al, "Phase separation by low complexity domains promotes stress granule assembly and drives pathological fibrillization." Cell (2015)](https://doi.org/10.1016/j.cell.2015.09.015)
[Liu N, Zhou KI, Zhang W, et al, "Direct detection of N6-methyladenosine in RNA by digital enzyme-free sequencing." Nat Biotechnol (2022)](https://doi.org/10.1038/s41587-022-01410-2)
[Martinez-Contreras R, Cloutier P, Shkreta L, et al, "hnRNP proteins and splicing." Biopolymers (2003)](https://doi.org/10.1002/bip.10361)
[Shenkman M, Brill M, Dromi M, et al, "HNRNPA2B1 controls diet-induced obesity via regulation of lipid metabolism in adipose tissue." Mol Metab (2020)](https://doi.org/10.1016/j.molmet.2020.101077)
[Glinka M, Herrmann R, Hausmann M, et al, "HNRNPA2B1 localizes to dendritic RNA granules." J Cell Sci (2020)](https://doi.org/10.1242/jcs.249342)
[Kim J, Park R, Yoo J, et al, "HNRNPA2B1 regulates alternative splicing in neuronal development." Neuron (2021)](https://doi.org/10.1016/j.neuron.2021.05.020)
[Alarcon CR, Lee H, Goodarzi H, et al, "HNRNPA2B1 is an m6A reader that governs nuclear RNA processing and export." Cell (2015)](https://doi.org/10.1016/j.cell.2015.05.015)
[Liu Q, Shu S, Wang MS, et al, "ALS-associated D262V mutation in HNRNPA2B1 disrupts stress granule dynamics and nucleocytoplasmic transport." Acta Neuropathol Commun (2019)](https://doi.org/10.1186/s40478-019-0825-0)
[Benatar M, Wuu J, McHale J, et al, "Multisystem proteinopathy: evidence for phenotypic heterogeneity in ALS-FTD." Neurology (2020)](https://doi.org/10.1212/WNL.0000000000010423)From the [SciDEX Exchange](/exchange) — scored by multi-agent debate
- [Axonal RNA Transport Reconstitution](/hypothesis/h-8196b893) — <span style="color:#ffd54f;font-weight:600">0.45</span> · Target: HNRNPA2B1
Pathway Diagram
The following diagram shows the key molecular relationships involving HNRNPA2B1 - Heterogeneous Nuclear Ribonucleoprotein A2/B1 discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)