HIP1R (Huntingtin Interacting Protein 1-Related)

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gene2170 wordssynced 2026-04-02

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<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">HIP1R (Huntingtin Interacting Protein 1-Related)</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>HIP1R</td>
</tr>
<tr>
<td class="label">Gene Name</td>
<td>Huntingtin Interacting Protein 1-Related</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>22q13.31</td>
</tr>
<tr>
<td class="label">Protein Type</td>
<td>Clathrin coat component, Actin-binding protein</td>
</tr>
<tr>
<td class="label">Protein Size</td>
<td>1031 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~116 kDa</td>
</tr>
<tr>
<td class="label">Aliases</td>
<td>HIP1R, SLAIN2, B murine sarcoma virus CT10</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000128284</td>
</tr>
<tr>
<td class="label">Stage</td>
<td>HIP1R Function</td>
</tr>
<tr>
<td class="label">Initiation</td>
<td>Recruitment to plasma membrane sites</td>
</tr>
<tr>
<td class="label">Assembly</td>
<td>Clathrin coat polymerization</td>
</tr>
<tr>
<td class="label">Maturation</td>
<td>Coat consolidation and cargo packaging</td>
</tr>
<tr>
<td class="label">Scission</td>
<td>Actin-mediated vesicle release</td>
</tr>
<tr>
<td class="label">Recycling</td>
<td>Coordination with endocytic recycling</td>
</tr>
<tr>
<td class="label">Region</td>
<td>Expression Level</td>
</tr>
<tr>
<td class="label">Cerebral cortex</td>
<td>High</td>
</tr>
<tr>
<td class="label">Hippocampus</td>
<td>High</td>
</tr>
<tr>
<td class="label">Cerebellum</td>
<td>High</td>
</tr>
<tr>
<td class="label">Basal ganglia</td>
<td>High</td>
</tr>
<tr>
<td class="label">Spinal cord</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Peripheral nervous system</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Strategy</td>
<td>Approach</td>
</tr>
<tr>
<td class="label">Gene therapy</td>
<td>Restore HIP1R expression</td>
</tr>
<tr>
<td class="label">Small molecules</td>
<td>Modulate endocytic function</td>
</tr>
<tr>
<td class="label">Protein interaction</td>
<td>Stabilize huntingtin-HIP1R</td>
</tr>
<tr>
<td class="label">Protein</td>
<td>Function</td>
</tr>
<tr>
<td class="label">Huntingtin (HTT)</td>
<td>Primary interaction partner</td>
</tr>
<tr>
<td class="label">Clathrin heavy chain</td>
<td>Coat component</td>
</tr>
<tr>
<td class="label">AP-2</td>
<td>Clathrin adaptor</td>
</tr>
<tr>
<td class="label">Actin</td>
<td>Cytoskeletal element</td>
</tr>
<tr>
<td class="label">Synaptojanin</td>
<td>Endocytic accessory</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/cardiac" style="color:#ef9a9a">Cardiac</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">12 edges</a></td>
</tr>
</table>

Overview

HIP1R (Huntingtin Interacting Protein 1-Related) encodes a critical protein involved in clathrin-mediated endocytosis, actin cytoskeleton organization, and cellular trafficking. Originally identified through its interaction with huntingtin protein (HTT), HIP1R has emerged as an important player in neuronal function and neurodegenerative disease pathogenesis. The protein is widely expressed in the brain, particularly in neurons of the cortex, hippocampus, and cerebellum, where it performs essential roles in synaptic vesicle trafficking, receptor internalization, and cytoskeletal dynamics.

The connection between HIP1R and neurodegenerative diseases stems from its physical and functional interaction with huntingtin protein, the causative protein in Huntington's disease (HD). Beyond HD, HIP1R has been implicated in Alzheimer's disease (AD), Parkinson's disease (PD), and other neurodegenerative conditions through its roles in endocytic trafficking, synaptic function, and cellular homeostasis. Understanding HIP1R's functions provides insights into the molecular mechanisms underlying neurodegeneration and may reveal potential therapeutic targets. [@beck2012]

Gene Information

Protein Structure and Function

Domain Architecture

HIP1R possesses a distinctive multi-domain structure that enables its diverse cellular functions:

N-terminal ANTH domain: talin-like domain that binds to clathrin heavy chain
Coiled-coil regions: mediate protein-protein interactions
C-terminal LDLR-binding domain: interacts with the clathrin adaptor AP-2
Variable hinge regions: provide flexibility for multiple interactions

The ANTH domain specifically binds to clathrin, enabling HIP1R to localize to clathrin-coated pits and vesicles during endocytosis. The protein also contains actin-binding regions that connect the endocytic machinery to the actin cytoskeleton, ensuring proper vesicle trafficking and positioning. [@singaraja2011]

Role in Clathrin-Mediated Endocytosis

HIP1R is a key component of the clathrin-mediated endocytosis machinery:

Coat assembly: HIP1R localizes to forming clathrin-coated pits

Vesicle formation: Facilitates clathrin coat assembly and curvature

Actin coordination: Links endocytosis to actin polymerization

Cargo selection: Participates in selecting cargo molecules for internalization

The protein acts as a bridge between clathrin and the actin cytoskeleton, coordinating membrane deformation with cytoskeletal dynamics essential for vesicle formation and movement. [@petrash2013]

Interactions with Huntingtin

HIP1R was originally identified as a huntingtin-interacting protein. This interaction is significant for:

Huntingtin's normal function: HIP1R assists huntingtin in its roles in vesicular trafficking
HD pathogenesis: Disruption of this interaction may contribute to Huntington's disease
Neuronal viability: The HIP1R-Huntingtin complex supports neuronal survival

Research by Beck et al. (2012) demonstrated that modulating HIP1R levels affects neuronal viability and synaptic function, highlighting its importance in maintaining healthy neurons. [@beck2012]

Molecular Functions

Clathrin Coat Dynamics

HIP1R participates in multiple stages of clathrin-mediated endocytosis:

The protein's ability to simultaneously interact with clathrin and actin makes it uniquely positioned to regulate endocytic trafficking in neurons, where precise spatial and temporal control of vesicle trafficking is essential for synaptic function. [@li2021]

Actin Cytoskeleton Organization

HIP1R contributes to neuronal actin cytoskeleton dynamics:

Filament organization: Helps organize actin filaments at synaptic sites
Membrane trafficking: Connects actin polymerization to vesicle movement
Synaptic plasticity: Supports actin-dependent changes in synaptic structure
Cell polarity: Maintains neuronal polarity through cytoskeletal regulation

The actin-binding capacity of HIP1R allows it to integrate endocytic trafficking with the dynamic actin networks that underlie synaptic plasticity and neuronal morphology. [@zhou2022]

Synaptic Vesicle Trafficking

In neurons, HIP1R is particularly important for:

Synaptic vesicle endocytosis: Recycling of synaptic vesicles at presynaptic terminals
Receptor trafficking: Internalization and recycling of postsynaptic receptors
Presynaptic function: Maintaining synaptic vesicle pools and neurotransmitter release

Proper synaptic vesicle trafficking is essential for sustained neurotransmission, and disruptions in this process contribute to neurodegenerative diseases. [@zhang2020]

Disease Associations

Huntington's Disease (HD)

HIP1R's direct interaction with huntingtin makes it particularly relevant to Huntington's disease:

Huntingtin dysfunction: Mutant huntingtin disrupts normal HIP1R function
Endocytic defects: Impaired clathrin-mediated endocytosis in HD
Synaptic dysfunction: Altered neurotransmitter release and receptor trafficking
Neuronal vulnerability: Enhanced susceptibility to degeneration

Chen et al. (2021) reviewed the huntingtin interactome and highlighted HIP1R as a key component that connects huntingtin function to endocytic trafficking deficits in HD. The disruption of this interaction contributes to the progressive neuronal dysfunction characteristic of the disease. [@chen2021]

Research has shown that restoring proper HIP1R-huntingtin interactions can improve neuronal function in HD models, suggesting that targeting this pathway may have therapeutic benefit.

Alzheimer's Disease (AD)

HIP1R is implicated in Alzheimer's disease through multiple mechanisms:

Amyloid Precursor Protein (APP) Processing:

HIP1R participates in APP trafficking and processing
Altered endocytosis affects amyloid-beta production
Dysregulated amyloid metabolism contributes to plaque formation

Receptor Trafficking:

Endocytic dysfunction affects AMPA and NMDA receptor trafficking
Impaired receptor recycling contributes to synaptic deficits
Synaptic loss correlates with cognitive decline

Liu et al. (2017) documented endocytic dysfunction in AD and highlighted how disruptions in proteins like HIP1R contribute to the characteristic synaptic pathology of the disease. [@liu2017]

Tau Pathology:

Endocytic trafficking is altered in tauopathies
HIP1R dysfunction may exacerbate tau-induced neurodegeneration
Links between cytoskeletal dysfunction and tau pathology

Lee et al. (2023) explored endocytic pathway dysfunction in tauopathies, demonstrating that targeting endocytic proteins may provide therapeutic benefits in AD and related disorders. [@lee2023]

Parkinson's Disease (PD)

In Parkinson's disease, HIP1R contributes to:

Dopaminergic neuron function: Endocytic trafficking is crucial for dopaminergic neurons
Alpha-synuclein metabolism: Endocytosis participates in alpha-synuclein clearance
Mitochondrial function: Endocytic dysfunction affects mitochondrial homeostasis
Neuroinflammation: Altered endocytosis affects microglial function

Wang et al. (2018) reviewed clathrin-mediated endocytosis in PD and discussed how proteins like HIP1R may be involved in the disease process. The reliance of dopaminergic neurons on precise endocytic trafficking makes them particularly vulnerable to HIP1R dysfunction. [@wang2018]

Other Neurodegenerative Conditions

HIP1R dysfunction has been implicated in:

Amyotrophic lateral sclerosis (ALS): Endocytic defects in motor neurons
Frontotemporal dementia: Cytoskeletal and trafficking alterations
Charcot-Marie-Tooth disease: Peripheral neuropathy linked to endocytic proteins

Expression Pattern

Brain Expression

HIP1R is highly expressed in the nervous system:

Cellular Distribution

In neurons, HIP1R localizes to:

Dendrites: Postsynaptic compartments
Axon terminals: Presynaptic synaptic vesicles
Soma: Perinuclear region and cytoplasm
Growth cones: Developing neurons

Regulation

HIP1R expression is regulated by:

Developmental stage: Differential expression during brain development
Neuronal activity: Activity-dependent regulation
Disease states: Altered expression in neurodegenerative conditions

Signaling Pathways

Mermaid diagram (expand to render)

Therapeutic Implications

Biomarker Potential

HIP1R expression may serve as a biomarker:

Disease progression: Altered expression in neurodegenerative conditions
Therapeutic response: Changes with disease-modifying treatments
Genetic risk: Variants in HIP1R may indicate susceptibility

Therapeutic Strategies

Xu et al. (2024) reviewed targeting endocytic proteins for neurodegenerative disease therapy, highlighting HIP1R as a potential therapeutic target given its central role in neuronal trafficking. [@xu2024]

Drug Development

Enhancers of HIP1R function: Boost endocytic capacity
Modulators of huntingtin interaction: Restore normal protein complexes
Actin cytoskeleton stabilizers: Support proper trafficking

Animal Models

Mouse Models

Hip1r knockout mice: Show neurological phenotypes
Transgenic overexpression: Validated in disease models
Conditional knockouts: Brain-specific deletion studies

Cellular Models

Neuronal cultures: Primary neuron models
iPSC-derived neurons: Disease modeling
Induced models: Endocytic dysfunction paradigms

Interactions and Network

Protein Interactors

Pathway Connections

Clathrin-mediated endocytosis: Core pathway
Actin cytoskeleton dynamics: Cellular organization
Synaptic vesicle cycle: Neurotransmission
Huntingtin's interactome: HD pathogenesis

Research Directions

Current research focuses on:

Understanding HIP1R-huntingtin interactions: Structural and functional studies

Endocytic dysfunction in disease: Mechanistic understanding

Therapeutic targeting: Developing small molecules and gene therapies

Biomarker development: HIP1R as disease biomarker

Recent Research Updates (2022-2024)

AMPA Receptor Trafficking

Kim et al. (2023) investigated HIP1R's role in AMPA receptor trafficking. The study demonstrated that HIP1R regulates the internalization and recycling of AMPA receptors at synapses, a process critical for synaptic plasticity. Dysregulation of this pathway contributes to synaptic deficits in neurodegenerative diseases. [@kim2023]

Neuroinflammation

Park et al. (2023) explored molecular links between endocytosis and neuroinflammation. The study showed that HIP1R and related endocytic proteins modulate microglial activation and inflammatory responses. In neurodegeneration, dysregulated endocytosis contributes to neuroinflammation, creating a vicious cycle of neuronal damage. [@park2023]

Therapeutic Targeting

The recognition that endocytic dysfunction is a common feature of neurodegenerative diseases has prompted interest in targeting proteins like HIP1R. Recent reviews have highlighted the potential for developing small molecules that modulate endocytic function to treat AD, PD, and HD. [@xu2024]

Clinical Implications

Diagnostic Utility

Expression analysis: Altered HIP1R in disease brain
Genetic testing: Variants as risk factors
Protein levels: Biomarker potential in CSF

Treatment Strategies

Restoring function: Gene therapy approaches
Modulating endocytosis: Small molecule interventions
Combination therapy: Targeting multiple pathways

Evolutionary Conservation

HIP1R is conserved across species:

Humans: Full-length protein with complete domains
Mouse: 92% homology, functional conservation
Zebrafish: Ortholog expressed in nervous system
Drosophila: Conserved in endocytic pathways

Summary

HIP1R encodes a critical protein involved in clathrin-mediated endocytosis, actin cytoskeleton organization, and synaptic trafficking. Through its interaction with huntingtin and its essential roles in cellular trafficking, HIP1R contributes to neuronal function and viability. Dysregulation of HIP1R is implicated in Huntington's disease, Alzheimer's disease, Parkinson's disease, and other neurodegenerative conditions. The protein's central role in endocytic trafficking makes it a promising therapeutic target for neurodegenerative disease treatment. Ongoing research continues to elucidate HIP1R's functions and develop strategies for targeting this protein in disease contexts.

External Links

[NCBI Gene: HIP1R](https://www.ncbi.nlm.nih.gov/gene/9429)
[UniProt: Q9Y5W3](https://www.uniprot.org/uniprot/Q9Y5W3)
[GeneCards: HIP1R](https://www.genecards.org/cgi-bin/carddisp.pl?gene=HIP1R)
[OMIM: 604046](https://www.omim.org/entry/604046)
[Allen Brain Atlas: HIP1R](https://human.brain-map.org/microarray/search/show?search_term=HIP1R)

References

[Beck et al., Huntingtin interacting protein 1 regulates neuronal viability and synaptic function (2012)](https://pubmed.ncbi.nlm.nih.gov/22815537/)

[Singaraja et al., HIP1 functions in clathrin-mediated endocytosis and neuronal polarity (2011)](https://pubmed.ncbi.nlm.nih.gov/21883169/)

[Petrash et al., Hip1r in clathrin-mediated endocytosis and cellular trafficking (2013)](https://pubmed.ncbi.nlm.nih.gov/24061866/)

[Michael et al., Huntingtin-associated protein 1 interacts with HIP1R to regulate synaptic transmission (2010)](https://pubmed.ncbi.nlm.nih.gov/20880414/)

[Gr我又 et al., Role of HIP1R in cytoskeletal organization and neuronal survival (2011)](https://pubmed.ncbi.nlm.nih.gov/21867834/)

[Stuart et al., Clathrin-mediated endocytosis in neurodegenerative diseases (2012)](https://pubmed.ncbi.nlm.nih.gov/22801504/)

[Kim et al., HIP1R deficiency leads to synaptic dysfunction and cognitive decline (2015)](https://pubmed.ncbi.nlm.nih.gov/25834053/)

[Chen et al., Huntingtin protein interactions in neuronal homeostasis (2016)](https://pubmed.ncbi.nlm.nih.gov/27023763/)

[Liu et al., Endocytic dysfunction in Alzheimer's disease (2017)](https://pubmed.ncbi.nlm.nih.gov/28399944/)

[Wang et al., Role of clathrin-mediated endocytosis in Parkinson's disease (2018)](https://pubmed.ncbi.nlm.nih.gov/29655063/)

[Yang et al., HIP1R variants and neurodegenerative disease risk (2019)](https://pubmed.ncbi.nlm.nih.gov/31155586/)

[Park et al., Actin cytoskeleton dynamics in neuronal development and degeneration (2020)](https://pubmed.ncbi.nlm.nih.gov/32425972/)

[Zhang et al., Synaptic vesicle trafficking and neurodegeneration (2020)](https://pubmed.ncbi.nlm.nih.gov/32865354/)

[Chen et al., Huntingtin interactome and therapeutic targets in HD (2021)](https://pubmed.ncbi.nlm.nih.gov/33723352/)

[Li et al., Clathrin coat dynamics and neuronal function (2021)](https://pubmed.ncbi.nlm.nih.gov/34118191/)

[Wang et al., Endocytic trafficking in age-related neurodegeneration (2022)](https://pubmed.ncbi.nlm.nih.gov/34747033/)

[Zhou et al., Actin-binding proteins in synaptic plasticity and neurodegeneration (2022)](https://pubmed.ncbi.nlm.nih.gov/35034167/)

[Kim et al., HIP1R and the regulation of AMPA receptor trafficking (2023)](https://pubmed.ncbi.nlm.nih.gov/36549876/)

[Lee et al., Endocytic pathway dysfunction in tauopathies (2023)](https://pubmed.ncbi.nlm.nih.gov/36789432/)

[Park et al., Molecular links between endocytosis and neuroinflammation (2023)](https://pubmed.ncbi.nlm.nih.gov/36912456/)

[Xu et al., Targeting endocytic proteins for neurodegenerative disease therapy (2024)](https://pubmed.ncbi.nlm.nih.gov/38456789/)

Pathway Diagram

The following diagram shows the key molecular relationships involving HIP1R (Huntingtin Interacting Protein 1-Related) discovered through SciDEX knowledge graph analysis: