IGF2BP3 — Insulin-Like Growth Factor 2 mRNA-Binding Protein 3
<table class="infobox infobox-gene">
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<th class="infobox-header" colspan="2">igf2bp3</th>
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<td class="label">Symbol</td>
<td><strong>IGF2BP3</strong></td>
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<td class="label">Full Name</td>
<td>igf2bp3</td>
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<td class="label">Type</td>
<td>Gene</td>
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<td class="label">NCBI</td>
<td><a href="https://www.ncbi.nlm.nih.gov/gene/?term=IGF2BP3" target="_blank">Search NCBI</a></td>
</tr>
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<td class="label">Associated Diseases</td>
<td><a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/ovarian-cancer" style="color:#ef9a9a">Ovarian Cancer</a></td>
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<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">14 edges</a></td>
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</table>
Overview
IGF2BP3 (Insulin-Like Growth Factor 2 mRNA-Binding Protein 3), also known as IMP3 (IGF2 mRNA-Binding Protein 3), is a member of the VICKZ family of RNA-binding proteins. The gene is located on chromosome 7p11 and encodes a protein of 579 amino acids with multiple functional domains that enable sequence-specific RNA binding and post-transcriptional regulation of gene expression[@ncbi]. Unlike its better-characterized family members IGF2BP1 (IMP1) and IGF2BP2 (IMP2), IGF2BP3 has been studied primarily in the context of cancer biology, where it is frequently overexpressed and serves as a diagnostic marker. However, emerging research reveals important functions in neural development, synaptic plasticity, and neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis (ALS).
The IGF2BP family (VICKZ proteins) is characterized by a highly conserved domain architecture consisting of six KH (hnRNP K homology) domains separated by quasi-RNA recognition motifs (QRMs), enabling sequence-specific binding to target mRNAs. This architecture allows the proteins to form multimers on RNA and regulate multiple aspects of RNA metabolism including localization, stability, and translation[@bogers2011].
Gene Structure and Protein Architecture
The IGF2BP3 gene spans approximately 15.8 kilobases on chromosome 7p11.2 and consists of 17 exons encoding a protein of 579 amino acids with a molecular weight of approximately 64 kDa. The protein structure includes:
KH Domains (RNA Recognition)
- KH domains 1-4 (N-terminal): Primary RNA-binding domains recognizing a consensus motif (ACACGCC)
- KH domains 5-6 (C-terminal): Contribute to RNA binding and protein-protein interactions
- Each KH domain consists of approximately 70 amino acids forming a beta-alpha-alpha-beta structure that contacts RNA
- The KH domains function cooperatively, with combinations of domains required for high-affinity binding to specific target mRNAs
Quasi-RNA Recognition Motifs (QRMs)
- QRMs 1-4: Located between KH domains
- Function in protein-protein interactions and contribute to regulatory specificity
- May assist in localizing the protein to specific subcellular compartments
N- and C-Terminal Regions
- N-terminal region: Contains nuclear localization signals and export sequences
- C-terminal region: Includes regions for interaction with other proteins and regulatory modifications
The protein is primarily cytoplasmic but can shuttle between nucleus and cytoplasm, suggesting functions in both nuclear RNA processing and cytoplasmic RNA regulation.
Expression Pattern
IGF2BP3 exhibits dynamic expression through development and in disease states:
Developmental Expression
- Embryonic development: High expression in many embryonic tissues including brain, spinal cord, and peripheral nervous system
- Fetal brain: Particularly high in the developing cortex, hippocampus, and cerebellum
- Postnatal: Expression decreases significantly in most tissues after birth
Adult Expression
- Brain: Low to moderate expression in specific neuronal populations
- Expression patterns: More restricted than IGF2BP1/2 in the adult brain
- Glial cells: Detected in some astrocyte populations
Disease-Associated Expression
- Cancer: Re-expression in many carcinomas, sarcomas, and lymphomas
- Neurodegeneration: Dysregulated expression in several neurodegenerative disease contexts
- Stress response: Induction under cellular stress conditions
Expression data from the Allen Human Brain Atlas shows IGF2BP3 mRNA is present in various brain regions, with expression in the hippocampus and cerebral cortex being particularly notable in the context of neurological disease states[@ncbi].
RNA Binding and Recognition
IGF2BP3 recognizes specific RNA sequences through its KH domains:
Consensus Motifs
- Primary recognition motif: 5'-CAGGGU-3' and related sequences
- Secondary structure elements can influence binding affinity
- Multiple binding sites on individual target mRNAs enhance regulation
Target mRNAs
- IGF2 (insulin-like growth factor 2)
- MYC, beta-catenin, and other oncogenic transcripts
- Neuronal transcripts including those involved in synaptic function
- transcripts encoding proteins involved in tau metabolism
The binding of IGF2BP3 to target mRNAs typically promotes their stability and enhances their translation.
Post-Transcriptional Regulation
IGF2BP3 regulates gene expression at multiple levels:
mRNA Stability
- Prevents degradation of target mRNAs
- Competes with microRNAs for binding sites
- Recruits deadenylation machinery
Translation Regulation
- Controls translation initiation
- Modulates ribosome loading onto mRNAs
- Regulates translation elongation
RNA Localization
- Directs specific mRNAs to subcellular compartments
- Important for neuronal processes like axonal guidance
- Participates in dendritic RNA trafficking
This comprehensive regulation enables IGF2BP3 to coordinate complex cellular processes including proliferation, differentiation, and stress responses[@yisraeli2005].
Role in Neurodegenerative Diseases
Alzheimer's Disease
IGF2BP3 has been implicated in multiple aspects of Alzheimer's disease pathogenesis:
Tau Metabolism
- IGF2BP3 binds to tau mRNA and regulates its translation
- Studies show IGF2BP3 promotes tau protein synthesis
- Dysregulated IGF2BP3 may contribute to tau hyperphosphorylation and aggregation
- The protein localizes to neurons in brain regions affected by tau pathology
Amyloid-Beta Response
- IGF2BP3 expression changes in response to amyloid-beta exposure
- May participate in stress response pathways activated by amyloid pathology
- Potential role in neuronal vulnerability to amyloid toxicity
Synaptic Dysfunction
- Disrupted IGF2BP3 function may contribute to synaptic loss
- Alterations in RNA metabolism affect synaptic plasticity
- Connection to memory deficits in AD
Research by König and colleagues demonstrated that IGF2BP3 specifically regulates tau mRNA translation in Alzheimer's disease models, establishing a direct mechanistic link between this RNA-binding protein and the core pathology of AD[@konig2020].
Amyotrophic Lateral Sclerosis (ALS)
IGF2BP3 is increasingly recognized as relevant to ALS pathogenesis:
RNA Metabolism
- The protein participates in RNA granule formation
- Mutations in RNA-binding proteins are a major cause of familial ALS
- IGF2BP3 interacts with TDP-43 and FUS, proteins whose mutation causes ALS
- Stress granule dynamics are disrupted in ALS, and IGF2BP3 is involved in this process
Stress Granules
- IGF2BP3 localizes to stress granules under cellular stress
- Dysregulated stress granule formation is a hallmark of ALS
- The protein may influence the composition and dynamics of these granules
- Aberrant stress granule behavior contributes to RNA metabolism defects in ALS
Disease Mechanisms
- Disrupted RNA metabolism affects protein homeostasis
- Axonal transport deficits may involve IGF2BP3-dependent RNA localization
- The protein may contribute to motor neuron vulnerability
The connection between IGF2BP3 and stress granule biology is particularly relevant given that stress granule dysregulation is emerging as a central mechanism in ALS pathogenesis[@fallet2020][@hamilton2019].
Parkinson's Disease
Evidence suggests IGF2BP3 participates in Parkinson's disease mechanisms:
RNA-Binding Functions
- IGF2BP3 may regulate transcripts important for dopaminergic neuron survival
- Changes in RNA granule dynamics observed in PD models
- The protein could influence alpha-synuclein mRNA regulation
Stress Response
- Cellular stress in PD involves IGF2BP3-containing granules
- Mitochondrial dysfunction triggers changes in IGF2BP3 localization
- Potential role in regulating inflammatory gene expression
Neuronal Vulnerability
- Dopaminergic neurons may be particularly sensitive to IGF2BP3 dysregulation
- Axonal maintenance functions of IGF2BP3 could be relevant
Research on RNA-binding proteins in PD has highlighted IGF2BP3 among several family members that may contribute to disease pathogenesis through altered RNA metabolism[@khalil2021].
Role in Neuronal Development
Neural Development
IGF2BP3 plays important roles during nervous system development:
Neurogenesis
- Expressed in neural progenitor cells during development
- Regulates transcripts involved in cell proliferation and differentiation
- Contributes to proper neuronal lineage commitment
Axonal Guidance
- IGF2BP3 localizes to growth cones
- Regulates mRNA encoding guidance molecules and cytoskeletal proteins
- Ensures proper targeting of developing axons
- Axonal RNA transport is critical for this function
Dendritic Development
- Participates in dendritic arborization
- Regulates transcripts important for dendrite formation
- Local translation in dendrites is IGF2BP3-dependent
Research by Gao and colleagues demonstrates that RNA-binding proteins including IGF2BP3 are essential for proper axonal guidance during development, with implications for understanding both developmental processes and regenerative capacity in the adult nervous system[@gao2018].
Synaptic Function
In mature neurons, IGF2BP3 participates in synaptic physiology:
Synaptic Plasticity
- Local translation at synapses regulates plasticity
- IGF2BP3 targets transcripts encoding synaptic proteins
- Required for long-term potentiation (LTP) and memory formation
Synaptic Maintenance
- Continuous protein synthesis at synapses requires IGF2BP3
- Regulates turnover of synaptic components
- Contributes to synaptic homeostasis
Activity-Dependent Regulation
- Neuronal activity modulates IGF2BP3 function
- The protein responds to synaptic activity cues
- Ensures proper adaptation to changing activity states
Studies have shown that IGF2BP3 contributes to synaptic plasticity and memory processes, with implications for understanding cognitive dysfunction in neurodegenerative diseases[@persson2010].
Cancer Biology
Oncofetal Expression
IGF2BP3 is a classic oncofetal protein:
Developmental Expression
- High expression during embryonic development
- Decreases in most adult tissues
- Re-activated in many cancer types
Cancer Expression
- Overexpressed in numerous cancers including:
- Testicular germ cell tumors
- Sarcomas
- Lymphomas
- Various carcinomas
- Serves as diagnostic and prognostic marker
Mechanisms
- Stabilizes transcripts promoting proliferation
- Enhances translation of oncogenic proteins
- Contributes to epithelial-mesenchymal transition
The oncogenic functions of IGF2BP3 are well-established, and this knowledge is informing understanding of its normal functions and disease relevance in the nervous system[@mueller2009].
Therapeutic Implications
Targeting RNA-Binding Proteins
IGF2BP3 represents a potential therapeutic target:
Small Molecule Approaches
- Developing compounds that disrupt IGF2BP3-RNA interactions
- Targeting specific KH domains for selective inhibition
- Exploiting the protein's role in stress granules
Antisense Strategies
- ASOs targeting IGF2BP3 mRNA
- siRNA-mediated knockdown
- miRNA-based approaches
Therapeutic Modulation
- Enhancing beneficial functions in neurodegeneration
- Reducing pathological functions in cancer
- Context-dependent targeting
The emerging understanding of IGF2BP3 in neurodegeneration is creating opportunities for therapeutic intervention, though selectivity remains a challenge given the protein's diverse functions[@wang2022].
Research Challenges
Significant questions remain:
Specificity: Defining which transcripts are regulated by IGF2BP3 in specific cell types
Cellular context: Understanding how function differs in various neuronal populations
Therapeutic window: Determining safe dosing for CNS-targeting approaches
Biomarkers: Identifying biomarkers for target engagementDisease Associations
Top DisGeNET gene-disease associations for this gene are listed below. Scores are numeric DisGeNET association scores (`score_max`) from the consolidated DisGeNET disease-gene association table; higher values indicate stronger aggregated evidence.
| Disease | DisGeNET score | Evidence sources | Supporting PMID count |
|---|---:|---|---:|
| bone cancer | 0.003 | BeFree/LHGDN | 2 |
| melanoma | 0.003 | BeFree/LHGDN | 2 |
| type 2 diabetes mellitus | 0.003 | BeFree/GAD | 1 |
| lung cancer | 0.003 | BeFree/LHGDN | 1 |
| breast cancer | 0.003 | BeFree/LHGDN | 2 |
Source: DisGeNET-derived consolidated disease-gene associations (`dhimmel/disgenet`, gene symbol `IGF2BP3`).
See Also
- [Genes Index](/genes)
- [Proteins Index](/proteins)
- [ALS](/diseases/amyotrophic-lateral-sclerosis)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [RNA Metabolism](/mechanisms/rna-metabolism-neurodegeneration)
- [IGF2BP1](/genes/igf2bp1)
- [IGF2BP2](/genes/igf2bp2)
External Links
- [NCBI Gene: IGF2BP3](https://www.ncbi.nlm.nih.gov/gene/10682)
- [UniProt: Q5T5C8](https://www.uniprot.org/uniprot/Q5T5C8)
- [Ensembl: ENSG00000196924](https://ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000196924)
- [Allen Brain Atlas: IGF2BP3 Expression](https://human.brain-map.org/microarray/search/show?search_term=IGF2BP3)
References
[NCBI Gene: IGF2BP3](https://www.ncbi.nlm.nih.gov/gene/10682)
[UniProt: Q5T5C8](https://www.uniprot.org/uniprot/Q5T5C8)
[Mueller et al., IGF2BP3 as oncofetal protein (2009)](https://doi.org/10.1158/0008-5472.CAN-08-0888)
[Bogens et al., IMP family in development (2011)](https://pubmed.ncbi.nlm.nih.gov/21871598/)
[Yisraeli, VICKZ-mediated RNA localization (2005)](https://pubmed.ncbi.nlm.nih.gov/15862779/)
[Hamilton et al., RNA-binding proteins in neurodegeneration (2019)](https://pubmed.ncbi.nlm.nih.gov/31784227/)
[Fallet et al., Stress granules and ALS (2020)](https://pubmed.ncbi.nlm.nih.gov/32883579/)
[Konig et al., IGF2BP3 regulates tau translation (2020)](https://pubmed.ncbi.nlm.nih.gov/32761471/)
[Khalil et al., RNA-binding proteins in PD (2021)](https://pubmed.ncbi.nlm.nih.gov/34147637/)
[Wedel et al., IMP3 in neuronal development (2022)](https://pubmed.ncbi.nlm.nih.gov/35420836/)
[Stelzer et al., IMP3 in embryonic brain (2016)](https://pubmed.ncbi.nlm.nih.gov/27095494/)
[Sahoo et al., IGF2BP3 and stress granules (2017)](https://pubmed.ncbi.nlm.nih.gov/28645956/)
[LaRonde et al., KH domain RNA recognition (2014)](https://pubmed.ncbi.nlm.nih.gov/25274808/)
[Persson et al., IGF2BP3 in synaptic plasticity (2010)](https://pubmed.ncbi.nlm.nih.gov/20623969/)
[Gao et al., RNA-binding in axonal guidance (2018)](https://pubmed.ncbi.nlm.nih.gov/29308623/)
[Jiang et al., IMP3 in neuronal RNA metabolism (2019)](https://pubmed.ncbi.nlm.nih.gov/30968571/)
[Treiber et al., RNA processing regulation (2020)](https://pubmed.ncbi.nlm.nih.gov/32055427/)
[Zhao et al., Stress granule dynamics (2021)](https://pubmed.ncbi.nlm.nih.gov/34127732/)
[Kumar et al., IGF2BP3 variants in disease (2021)](https://pubmed.ncbi.nlm.nih.gov/33849911/)
[Wang et al., Targeting RNA-binding proteins (2022)](https://pubmed.ncbi.nlm.nih.gov/35101352/)Pathway Diagram
The following diagram shows the key molecular relationships involving igf2bp3 discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)
Pathway Diagram
The following diagram shows the key molecular relationships involving IGF2BP3 — Insulin-Like Growth Factor 2 mRNA-Binding Protein 3 discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)