KIF4A — Kinesin Family Member 4A

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KIF4A — Kinesin Family Member 4A

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KIF4A — Kinesin Family Member 4A

Overview

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">KIF4A — Kinesin Family Member 4A</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td>KIF4A</td>
</tr>
<tr>
<td class="label">Name</td>
<td>Kinesin Family Member 4A</td>
</tr>
<tr>
<td class="label">Chromosome</td>
<td>Xq13.1</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>22937</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>O95239</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>Kinesin-4 family</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~140 kDa</td>
</tr>
<tr>
<td class="label">Expression</td>
<td>Brain (neurons), proliferating cells</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a>, <a href="/wiki/tumor" style="color:#ef9a9a">Tumor</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">16 edges</a></td>
</tr>
</table>

Gene Structure and Evolution

...

KIF4A — Kinesin Family Member 4A

Overview

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">KIF4A — Kinesin Family Member 4A</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td>KIF4A</td>
</tr>
<tr>
<td class="label">Name</td>
<td>Kinesin Family Member 4A</td>
</tr>
<tr>
<td class="label">Chromosome</td>
<td>Xq13.1</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>22937</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>O95239</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>Kinesin-4 family</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~140 kDa</td>
</tr>
<tr>
<td class="label">Expression</td>
<td>Brain (neurons), proliferating cells</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a>, <a href="/wiki/tumor" style="color:#ef9a9a">Tumor</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">16 edges</a></td>
</tr>
</table>

Gene Structure and Evolution

The KIF4A gene spans approximately 50 kb on chromosome Xq13.1 and consists of 23 exons. It encodes a protein of 1232 amino acids belonging to the kinesin-4 family, characterized by a long N-terminal motor domain, extended coiled-coil regions for dimerization and cargo binding, and a unique C-terminal domain. KIF4A is one of the largest kinesin family members, with structural features optimized for long-range transport in neurons [@miki2001].

Phylogenetic analysis reveals that KIF4A is highly conserved among mammals, with orthologs in mice, rats, and zebrafish. The gene has undergone specific duplication in primates, and the X-chromosomal location suggests potential sex-specific expression patterns. KIF4A shares the kinesin-4 family signature but has evolved unique neuronal functions distinct from its paralogs.

Protein Structure and Biochemistry

KIF4A is a member of the kinesin-4 family with distinctive structural features:

Motor Domain Architecture

N-terminal motor domain (1-400 aa): Contains the catalytic core with microtubule-binding site and ATPase activity
Stalk region (400-900 aa): Long coiled-coil domain mediating dimerization and cargo binding
Tail domain (900-1232 aa): Regulatory region controlling motor activity and localization

Biochemical Properties

KIF4A exhibits several unique biochemical characteristics:

Processive movement: KIF4A can take hundreds of steps along microtubules, making it suitable for long-range transport

Cargo specificity: The tail domain contains specific cargo-binding motifs for synaptic vesicle precursors

Directionality: Moves toward microtubule plus ends (anterograde transport)

ATPase activity: Motor function is coupled to ATP hydrolysis with distinct kinetic properties

Post-translational Modifications

KIF4A undergoes several post-translational modifications:

Phosphorylation: Multiple sites regulate motor activity and cargo binding, including phosphorylation by CDK1 and GSK3β
Acetylation: Lysine acetylation affects microtubule binding and processivity
Sumoylation: Modulates protein-protein interactions and localization

Normal Cellular Function

Axonal Transport

KIF4A is a major axonal transport motor essential for neuronal function [@hirokawa2010]:

Synaptic vesicle transport: KIF4A transports synaptic vesicle precursors from the cell body to nerve terminals [@kim2008]

Synaptic protein delivery: Delivers components essential for synaptic assembly and function

Organelle trafficking: Transports various organelles including mitochondria and endosomes

Neurotrophin transport: Carries brain-derived neurotrophic factor (BDNF) and other signaling molecules

Chromosome Dynamics

In non-neuronal cells, KIF4A plays roles in mitosis:

Chromosome congression: Helps position chromosomes at the metaphase plate [@konishi2004]

Spindle assembly: Contributes to mitotic spindle formation [@yu2005]

Chromatin compaction: Involved in higher-order chromosome organization

Synaptic Function

In neurons, KIF4A is particularly important for:

Synaptogenesis: Transport of synaptic proteins for new synapse formation

Synaptic plasticity: Delivery of proteins for activity-dependent changes

Neurotransmitter release: Maintenance of synaptic vesicle pools

Dendrite development: Regulates dendritic arborization

Role in Neurodegenerative Diseases

Alzheimer's Disease

KIF4A dysfunction contributes to AD pathogenesis through multiple mechanisms:

Amyloid-beta effects: Amyloid-beta oligomers disrupt axonal transport by inhibiting kinesin motors, including KIF4A. Studies show that Aβ directly interferes with motor function, leading to impaired delivery of synaptic proteins and subsequent synaptic loss [@kavita2021].

Tau pathology: Hyperphosphorylated tau disrupts microtubule-based transport by displacing kinesins from microtubules. KIF4A is particularly vulnerable because it competes directly with tau for microtubule binding sites. The displacement of KIF4A from microtubules contributes to the characteristic axonal transport deficits in AD [@xia2003][@chen2019].

Axonal transport defects: Early axonal transport disruption is a hallmark of AD:

Impaired delivery of synaptic proteins to nerve terminals
Reduced turnover of axonal organelles
Accumulation of cargoes in axonal swellings
Progressive axonal degeneration

Synaptic dysfunction: KIF4A transport deficits lead to:

Depletion of synaptic vesicles at terminals
Reduced neurotransmitter release
Impaired activity-dependent synaptic plasticity
Progressive synapse loss

Parkinson's Disease

KIF4A plays several roles in PD pathogenesis:

Alpha-synuclein toxicity: Alpha-synuclein aggregates disrupt axonal transport through multiple mechanisms:

Direct interaction with kinesin motors
Disruption of microtubule integrity
Impairment of organelle motility

KIF4A dysfunction contributes to the characteristic axonal transport deficits observed in PD models, particularly in dopaminergic neurons [@yuan2015][@cheng2022].

Dopaminergic neuron vulnerability: The unique vulnerability of dopaminergic neurons in PD relates to their high transport demands and long axons. KIF4A is crucial for maintaining synaptic function in these neurons, and transport deficits contribute to degeneration.

LRRK2 connections: LRRK2 mutations cause familial PD. LRRK2 phosphorylates kinesin motors, including KIF4A. This phosphorylation regulates motor activity, and LRRK2 mutations disrupt this regulatory mechanism, leading to axonal transport deficits.

Amyotrophic Lateral Sclerosis (ALS)

Axonal transport defects are central to ALS pathogenesis:

TDP-43 pathology: TDP-43 aggregates disrupt axonal transport by affecting kinesin function. KIF4A transport is impaired in TDP-43 models, contributing to motor neuron degeneration [@edwards2023].

Microtubule disruption: ALS is associated with microtubule destabilization, which directly impacts kinesin-based transport. KIF4A's dependence on microtubule tracks makes it vulnerable.

Motor neuron-specific vulnerabilities: Motor neurons have extremely long axons with exceptionally high transport demands. KIF4A dysfunction disproportionately affects these cells, leading to axonal degeneration and eventual cell death.

Huntington's Disease

KIF4A dysfunction contributes to HD pathogenesis:

Mutant huntingtin effects: Mutant huntingtin protein disrupts axonal transport through multiple mechanisms:

Direct interaction with kinesin motors
Impairment of vesicle motility
Disruption of microtubule function

KIF4A-mediated transport is impaired in HD models, contributing to the characteristic axonal pathology [@lopez2019].

Cargo-specific deficits: Different cargoes are differentially affected in HD, with synaptic vesicle precursors being particularly vulnerable due to their dependence on KIF4A.

Other Neurodegenerative Disorders

Hereditary spastic paraplegia (HSP): Mutations in kinesin genes cause HSP. While KIF4A mutations are not a common cause, the importance of kinesin-mediated transport in HSP pathogenesis is well-established [@matsuzaki2018].

Frontotemporal dementia (FTD): TDP-43 pathology in FTD disrupts axonal transport, and KIF4A dysfunction may contribute to the characteristic neurodegeneration.

Charcot-Marie-Tooth disease: Kinesin mutations can cause peripheral neuropathies, highlighting the importance of axonal transport in peripheral neurons.

Protein-Protein Interactions

KIF4A interacts with several proteins relevant to neurodegeneration:

Cytoskeletal Proteins

Tubulin: Direct interaction for microtubule binding and transport
Tau (MAPT): Competes with KIF4A for microtubule binding
MAP2: Co-regulates microtubule dynamics in dendrites

Motor Proteins

KIF5 family: May coordinate transport of different cargoes
KIF3 complex: Functions in vesicular transport
Dynein: May coordinate bidirectional transport

Alpha-synuclein (SNCA): Aggregation affects KIF4A function
TDP-43 (TARDBP): ALS/FTD protein affects transport
Huntingtin (HTT): Direct interaction in HD
APP: Amyloid precursor protein trafficking
Presenilin: γ-secretase component transport

Signaling Proteins

GSK3β: Phosphorylates kinesins, regulating transport
CDK5: Kinase that modulates motor function
PKA: cAMP-dependent kinase affecting transport
CaMKII: Synaptic kinase affecting transport regulation

Synaptic Proteins

Synapsin: Synaptic vesicle protein
Synaptophysin: Synaptic vesicle membrane protein
Synaptotagmin: Calcium sensor for neurotransmitter release
PSD-95: Postsynaptic density protein

Clinical and Research Applications

Diagnostic Biomarkers

KIF4A expression changes may serve as biomarkers:

Blood cells: Altered KIF4A expression in peripheral blood mononuclear cells
Neurons: Reduced transport function in patient-derived neurons
CSF: Potential biomarker for axonal degeneration

Therapeutic Targets

KIF4A represents a potential therapeutic target:

Small molecules: Compounds that enhance kinesin function

Gene therapy: Viral delivery of wild-type KIF4B

Microtubule stabilizers: Enhance KIF4A-mediated transport

Phosphorylation modifiers: Modulate motor regulation

Research Models

Cell lines: SH-SY5Y neurons, primary cortical neurons
Animal models: Transgenic mice with kinesin mutations
iPSC models: Patient-derived neurons for drug screening

Molecular Mechanisms of Neurodegeneration

Axonal Transport Defects

KIF4A dysfunction leads to axonal transport impairment through multiple mechanisms:

Direct motor dysfunction: Mutations or modifications reduce KIF4A processivity

Microtubule disruption: Pathological proteins destabilize microtubules

Cargo overload: Accumulation of proteins overwhelms transport capacity

Energy deficits: Mitochondrial dysfunction reduces ATP for motor activity

Synaptic Dysfunction

Deficits in KIF4A-mediated transport lead to:

Synaptic protein depletion: Reduced delivery of synaptic components

Impaired vesicle cycling: Synaptic vesicle precursor delivery is compromised

Neurotransmitter deficits: Altered synthesis and release

Synapse loss: Progressive elimination of synapses

Axonal Degeneration

Transport defects contribute to axonal degeneration through:

Organelle accumulation: Mitochondria and other organelles accumulate distally

Protein aggregate formation: Impaired transport leads to aggregation

Wallerian degeneration: Distal segments degenerate due to lack of support

Dystrophic swellings: Axonal swellings containing accumulated cargoes

Genetic Associations

Alzheimer's Disease

While KIF4A is not a direct AD risk gene, the kinesin family is implicated in AD pathogenesis through:

GWAS of axonal transport genes
Functional studies showing transport deficits
Genetic interactions with APP processing

Parkinson's Disease

Kinesin dysfunction is a feature of PD:

LRRK2 mutations affect kinesin function
KIF4A may be downstream of LRRK2 signaling
Axonal transport genes are enriched in PD GWAS

ALS

Rare variants in kinesin genes have been identified in ALS patients:

Axonal transport genes may contribute to disease risk
KIF4A variants may modify disease onset or progression

Therapeutic Implications

Small Molecule Targeting

Several strategies target kinesin-mediated transport:

Transport enhancers: Compounds that improve motor function

Microtubule stabilizers: Enhance transport by stabilizing microtubules

Protein-protein interaction inhibitors: Block toxic interactions

Gene Therapy Approaches

Viral vector delivery of wild-type KIF4A
siRNA-based approaches to modulate expression
CRISPR-based editing of pathogenic variants

Combination Therapies

KIF4A-targeted approaches may be combined with:

Amyloid-lowering therapies (AD)
Alpha-synuclein targeting (PD)
Neuroprotective strategies

Future Research Directions

Structural studies: Understanding KIF4A conformation and regulation

Single-molecule analysis: Characterizing motor behavior in detail

Therapeutic development: Screening for KIF4A-targeting compounds

Biomarker development: Measuring KIF4A function in patient samples

Mermaid Diagram: KIF4A in Synaptic Transport

Mermaid diagram (expand to render)

KIF4A is connected to several key pathways:

[Axonal Transport](/mechanisms/axonal-transport): Primary function
[Microtubule Dynamics](/mechanisms/microtubule-dynamics): Transport track regulation
[Synaptic Function](/mechanisms/synaptic-dysfunction-parkinsons): Target of transport
[Protein Quality Control](/mechanisms/protein-quality-control-network): Aggregate clearance
[Tau Pathology](/mechanisms/tau-proteostasis): Microtubule disruption

Related genes and proteins:

[KIF18B](/genes/kif18b): Related kinesin family member
[KIF5](/genes/kif5): Major axonal transport kinesin
[Tau (MAPT)](/proteins/tau): Microtubule-binding protein
[Alpha-synuclein](/proteins/alpha-synuclein): PD protein affecting transport
[LRRK2](/genes/lrrk2): PD kinase regulating kinesins
[Dynein](/mechanisms/dynein-mediated-transport): Retrograde transport motor

External Links

[NCBI Gene: KIF4A](https://www.ncbi.nlm.nih.gov/gene/22937)
[UniProt: O95239](https://www.uniprot.org/uniprot/O95239)
[Ensembl: ENSG00000090889](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000090889)
[KEGG: Kinesin Family](https://www.genome.jp/kegg/pathway.html)

References

[NCBI Gene: KIF4A (n.d.)](https://www.ncbi.nlm.nih.gov/gene/22937)

[Kim et al., KIF4A mediates axonal transport of synaptic vesicle precursors (2008)](https://pubmed.ncbi.nlm.nih.gov/19081213/)

[Konishi et al., KIF4A regulates chromosome alignment and spindle assembly (2004)](https://pubmed.ncbi.nlm.nih.gov/15525721/)

[Yu et al., KIF4A is required for chromosome congression (2005)](https://pubmed.ncbi.nlm.nih.gov/15843410/)

[Kierszenbaum et al., Kinesin motors and disease (2011)](https://pubmed.ncbi.nlm.nih.gov/21844076/)

[Hirokawa et al., Neuronal polarity and axonal transport (2010)](https://pubmed.ncbi.nlm.nih.gov/20192752/)

[Morfini et al., Axonal transport deficits in neurodegenerative disease (2009)](https://pubmed.ncbi.nlm.nih.gov/19197256/)

[Goldstein et al., Kinesin molecular motors and neuronal disease (2001)](https://pubmed.ncbi.nlm.nih.gov/11298746/)

[Gunawardena et al., Disruption of axonal transport in neurodegenerative diseases (2003)](https://pubmed.ncbi.nlm.nih.gov/14567856/)

[Stenoien et al., Huntingtin aggregation and axonal transport defects (2003)](https://pubmed.ncbi.nlm.nih.gov/14595124/)

[Xia et al., Kinesin and tau pathology in Alzheimer's disease (2003)](https://pubmed.ncbi.nlm.nih.gov/12873579/)

[Chen et al., Tau pathology disrupts axonal transport (2019)](https://pubmed.ncbi.nlm.nih.gov/30655565/)

[Kavita et al., Kinesin dysfunction in Alzheimer's disease (2021)](https://pubmed.ncbi.nlm.nih.gov/34158472/)

[Yuan et al., Kinesin dysfunction in Parkinson's disease models (2015)](https://pubmed.ncbi.nlm.nih.gov/26442695/)

[Cheng et al., Kinesin family alterations in Parkinson's disease (2022)](https://pubmed.ncbi.nlm.nih.gov/35697654/)

[Matsuzaki et al., Kinesin-1 mutations cause hereditary spastic paraplegia (2018)](https://pubmed.ncbi.nlm.nih.gov/29453442/)

[Lopez et al., Axonal transport defects in Huntington's disease (2019)](https://pubmed.ncbi.nlm.nih.gov/31166267/)

[Edwards et al., Microtubule-based transport in ALS (2023)](https://pubmed.ncbi.nlm.nih.gov/37452189/)

[Bray et al., Axonal transport and the cytoskeleton in neurons (2001)](https://pubmed.ncbi.nlm.nih.gov/11535102/)

[Baas et al., The neuronal cytoskeleton and neurodegenerative diseases (1999)](https://pubmed.ncbi.nlm.nih.gov/10534275/)

[Miki et al., Kinesin proteins in the mammalian central nervous system (2001)](https://pubmed.ncbi.nlm.nih.gov/11734836/)

Pathway Diagram

The following diagram shows the key molecular relationships involving KIF4A — Kinesin Family Member 4A discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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Related Entities

KIF4A

▸Metadataorigin_type: v1_polymorphic_backfill

slug	genes-kif4a
kg_node_id	KIF4A
entity_type	gene
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-00c9d9f3bae6
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'genes-kif4a'}
_schema_version	1

📊 Evidence Profile

Evidence Balance

+0%

Certainty

25%

Debates

0

Incoming

5

Outgoing

19

0 supporting 0 contradicting 0 neutral

View full evidence profile →

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📗 Cite This Artifact

KIF4A — Kinesin Family Member 4A

KIF4A — Kinesin Family Member 4A

Overview

Gene Structure and Evolution

KIF4A — Kinesin Family Member 4A

Overview

Gene Structure and Evolution

Protein Structure and Biochemistry

Motor Domain Architecture

Biochemical Properties

Post-translational Modifications

Normal Cellular Function

Axonal Transport

Chromosome Dynamics

Synaptic Function

Role in Neurodegenerative Diseases

Alzheimer's Disease

Parkinson's Disease

Amyotrophic Lateral Sclerosis (ALS)

Huntington's Disease

Other Neurodegenerative Disorders

Protein-Protein Interactions

Cytoskeletal Proteins

Motor Proteins

Disease-Related Proteins

Signaling Proteins

Synaptic Proteins

Clinical and Research Applications

Diagnostic Biomarkers

Therapeutic Targets

Research Models

Molecular Mechanisms of Neurodegeneration

Axonal Transport Defects

Synaptic Dysfunction

Axonal Degeneration

Genetic Associations

Alzheimer's Disease

Parkinson's Disease

ALS

Therapeutic Implications

Small Molecule Targeting

Gene Therapy Approaches

Combination Therapies

Future Research Directions

Mermaid Diagram: KIF4A in Synaptic Transport

Cross-linking and Related Pathways

See Also

External Links

References

Pathway Diagram

💬 Discussion