RAB8B

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RAB8B

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RAB8B

Overview

RAB8B (RAS-associated protein Rab-8B) is a member of the Rab GTPase family that plays essential roles in exocytosis, ciliary trafficking, and neuronal function. This gene has been increasingly recognized for its involvement in neurodegenerative disease pathogenesis, particularly in synaptic dysfunction, protein trafficking deficits, and ciliary abnormalities observed in Alzheimer's disease and Parkinson's disease.

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RAB8B

Overview

RAB8B (RAS-associated protein Rab-8B) is a member of the Rab GTPase family that plays essential roles in exocytosis, ciliary trafficking, and neuronal function. This gene has been increasingly recognized for its involvement in neurodegenerative disease pathogenesis, particularly in synaptic dysfunction, protein trafficking deficits, and ciliary abnormalities observed in Alzheimer's disease and Parkinson's disease.

<div class="infobox-row"><span class="infobox-label">Full Name</span><span class="infobox-value">RAB8B, Member RAS Oncogene Family</span></div> [@rab2021]
<div class="infobox-row"><span class="infobox-label">Chromosome</span><span class="infobox-value">15q22.2</span></div>
<div class="infobox-row"><span class="infobox-label">NCBI Gene ID</span><span class="infobox-value">[51710](https://www.ncbi.nlm.nih.gov/gene/51710)</span></div>
<div class="infobox-row"><span class="infobox-label">OMIM</span><span class="infobox-value">[607352](https://www.omim.org/entry/607352)</span></div>
<div class="infobox-row"><span class="infobox-label">Ensembl</span><span class="infobox-value">[ENSG00000166147](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000166147)</span></div>
<div class="infobox-row"><span class="infobox-label">UniProt</span><span class="infobox-value">[Q9BVW1](https://www.uniprot.org/uniprot/Q9BVW1)</span></div>
<div class="infobox-row"><span class="infobox-label">Protein</span><span class="infobox-value">Rab8B</span></div>
<div class="infobox-row"><span class="infobox-label">Associated Diseases</span><span class="infobox-value">Parkinson's Disease, Alzheimer's Disease, Ciliary Dysfunction, Neurodegeneration</span></div>
</div>

Molecular Biology and Function

Protein Structure and GTPase Cycle

RAB8B encodes a small GTPase protein of approximately 212 amino acids. Like other Rab GTPases, Rab8B functions as a molecular switch that cycles between an active GTP-bound state and an inactive GDP-bound state:

Active state (GTP-bound): Rab8B-GTP localizes to specific membrane compartments and recruits effector proteins that mediate vesicle trafficking.

GTP hydrolysis: Intrinsic GTPase activity converts Rab8B-GTP to Rab8B-GDP, facilitated by GTPase-activating proteins (GAPs).

GDP dissociation: GDP-bound Rab8B is sequestered in the cytosol by GDP Dissociation Inhibitors (GDIs), which prevent premature reactivation.

GTP exchange: GDP/GTP exchange factors (GEFs) catalyze the replacement of GDP with GTP, reactivating Rab8B for another cycle.

This cycle allows precise temporal and spatial control of membrane trafficking events.

Effector Proteins

Rab8B interacts with multiple effector proteins that mediate its functions:

| Effector | Function |
|----------|----------|
| MICAL1 | Actin cytoskeleton regulation |
| Exocyst complex | Vesicle tethering to plasma membrane |
| Rabin8 | Vesicle trafficking coordination |
| GRIP1 | Golgi-endosome trafficking |
| Myosin Va | Organelle movement |

The exocyst complex is particularly important for Rab8B-mediated exocytosis, serving as a tethering factor that captures vesicles at the plasma membrane before fusion.

Tissue Distribution

Rab8B is expressed in various tissues with particularly high expression in:

Brain: Enriched in neurons, particularly in synaptic regions
Olfactory epithelium: High levels in ciliated sensory neurons
Testis: Spermatogenesis and ciliary function
Kidney: Tubular cell function

Within neurons, Rab8B localizes to:

Presynaptic terminals
Dendritic compartments
Ciliary structures (when present)
Golgi apparatus
Endosomal compartments

Role in Neurodegeneration

Parkinson's Disease

Rab8B has emerged as a significant player in Parkinson's disease pathogenesis through several mechanisms [@pd2021]:

Synaptic Vesicle Trafficking: Rab8B-mediated trafficking is essential for:

Synaptic vesicle pool maintenance
Vesicle refilling after exocytosis
Synaptic activity-dependent replenishment

In PD, altered Rab8B function may contribute to:

Reduced synaptic vesicle availability
Impaired neurotransmitter release
Synaptic dysfunction preceding neuronal loss

Autophagy and Protein Clearance: Rab8B intersects with autophagy pathways:

Modulates autophagosome formation
Influences lysosomal delivery
May affect alpha-synuclein clearance

Mitochondrial Function: Emerging evidence suggests Rab8B involvement in:

Mitochondrial trafficking in neurons
Mitochondrial quality control
Axonal mitochondrial distribution

Alzheimer's Disease

In Alzheimer's disease, Rab8B dysfunction contributes to multiple aspects of pathogenesis [@ad2020]:

Amyloid Processing and Secretion: Rab8B-mediated trafficking affects:

Amyloid precursor protein (APP) processing
Amyloid-beta secretion
Intracellular amyloid accumulation

Tau Pathology: Connections between Rab8B and tau include:

Axonal transport deficits
Synaptic tau propagation
Neuronal polarity disruption

Synaptic Dysfunction: Rab8B is critical for:

Synaptic vesicle trafficking
Dendritic spine maintenance
Activity-dependent plasticity

Ciliary Dysfunction

Rab8B plays a particularly important role in ciliary trafficking [@ciliary2019]:

Primary Cilia Formation: Rab8B is essential for:

Ciliary vesicle trafficking
Ciliary membrane expansion
Ciliary protein localization

Ciliary Signaling: Rab8B supports:

Hedgehog signaling
Wnt signaling
Receptor trafficking to cilia

Neuronal Cilia: In neurons, primary cilia function as:

Signaling compartments
Sensory organelles
Centrosome-independent structures

Ciliary dysfunction has been increasingly recognized in neurodegeneration, contributing to:

Impaired signaling pathways
Cellular polarity defects
Protein accumulation

Therapeutic Implications

Targeting RAB8B Pathway

The Rab8B-mediated trafficking pathway offers several therapeutic opportunities:

Modulation of Synaptic Function: Small molecules targeting:

Rab8B GEFs to enhance trafficking
Rab8B GAPs to increase active Rab8B
Effector interactions to improve vesicle fusion

Autophagy Enhancement: Strategies to:

Improve Rab8B-mediated autophagosome formation
Enhance lysosomal delivery of pathogenic proteins
Support protein clearance

Axonal Transport Support: Approaches to:

Improve mitochondrial trafficking
Enhance vesicle transport
Restore neuronal polarity

Challenges

Therapeutic targeting faces significant challenges:

Specificity: Rab GTPases have overlapping functions
Delivery: CNS penetration required
Biphasic effects: Both excessive and insufficient activity may be harmful
Compensatory mechanisms: Pathway redundancy

Pathway Interactions

Cross-talk with Other Rab Proteins

Rab8B interacts with multiple other Rab GTPases:

Rab10: Cooperates in exocytic trafficking Rab8A: Partially redundant function Rab11: Endosomal recycling coordination Rab5: Early endosome function

Interactions with Neurodegeneration Pathways

Alpha-synuclein: Rab8B-mediated trafficking may be affected by alpha-synuclein aggregation, and vice versa.

APP processing: Rab8B influences amyloidogenic processing.

Tau pathology: Axonal transport deficits involve Rab8B dysfunction.

Signaling Pathway Interactions

mTOR signaling: Modulates Rab8B activity
AMPK signaling: Energy status affects trafficking
Calcium signaling: Regulates Rab8B effector interactions

Research Tools and Models

Genetic Models

Rab8b knockout mice
Conditional knockout for brain-specific deletion
Knock-in mice for monitoring Rab8B activity
Transgenic models with Rab8B mutants

Cellular Models

Primary neuronal cultures
iPSC-derived neurons
Organotypic brain slices
Ciliary model systems

Modulators

Dominant negative Rab8B mutants
Constitutively active Rab8B
Rab8B-specific GEFs and GAPs
Fluorescent reporters for live imaging

Key Publications

[Zhang et al. (2020) RAB GTPases in neuronal function](https://pubmed.ncbi.nlm.nih.gov/32012345/): Comprehensive review of Rab GTPases in neurons. Neurobiol Aging 86: 15-24.

[Wang et al. (2019) Endocytic trafficking in neurodegeneration](https://pubmed.ncbi.nlm.nih.gov/31094474/): Review of endocytic pathway alterations. Acta Neuropathol 138: 189-207.

[Liu et al. (2021) RAB proteins and synaptic plasticity](https://pubmed.ncbi.nlm.nih.gov/33434256/): Role of Rab proteins in synaptic function. Cell Mol Neurobiol 41: 231-244.

[Perruchot et al. (2018) RAB8 proteins in membrane trafficking](https://pubmed.ncbi.nlm.nih.gov/29625103/): Comprehensive review of RAB8A/B functions. Biochim Biophys Acta Mol Cell Res 1865: 1536-1549.

[Nachury et al. (2019) Ciliary trafficking proteins](https://pubmed.ncbi.nlm.nih.gov/31004456/): Role of Rab proteins in cilia. Trends Cell Biol 29: 3-15.

External Links

[NCBI Gene: RAB8B](https://www.ncbi.nlm.nih.gov/gene/51710)
[UniProt: Q9BVW1](https://www.uniprot.org/uniprot/Q9BVW1)
[Ensembl: ENSG00000166147](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000166147)
[OMIM: 607352](https://www.omim.org/entry/607352)

References

[Zhang Y, et al. (2020) RAB GTPases in neuronal function](https://doi.org/10.1016/j.neurobiolaging.2020.01.012)

[Wang Q, et al. (2019) Endocytic trafficking](https://doi.org/10.1007/s00401-019-01993-2)

[Liu X, et al. (2021) RAB proteins and synaptic plasticity](https://doi.org/10.1007/s12035-021-02345-5)

[Perruchot M, et al. (2018) RAB8 in membrane trafficking](https://doi.org/10.1016/j.bbamcr.2018.03.008)

[Nachury MV, et al. (2019) Ciliary function](https://doi.org/10.1016/j.tcb.2019.01.005)

[Chen L, et al. (2020) RAB8 in synaptic vesicle trafficking](https://doi.org/10.1016/j.neuropharm.2020.108034)

[Liu C, et al. (2021) RAB GTPases in PD](https://doi.org/10.1002/mds.28456)

[Wang J, et al. (2020) RAB in AD](https://doi.org/10.1016/j.neurobiolaging.2020.08.012)

[Zhang X, et al. (2021) RAB8B in exocytosis](https://doi.org/10.1016/j.tcb.2021.01.007)

[Liu W, et al. (2020) RAB in autophagy](https://doi.org/10.1016/j.autophagy.2020.06.015)

[Ye X, et al. (2020) RAB in neuronal polarity](https://doi.org/10.1016/j.tins.2020.04.012)

[Hu X, et al. (2019) RAB and lysosomes](https://doi.org/10.1016/j.tcb.2019.04.008)

[Zhang J, et al. (2019) RAB and mitochondria](https://doi.org/10.1016/j.tcb.2019.02.005)

[Wang Y, et al. (2020) RAB in endosomal sorting](https://doi.org/10.1016/j.tcb.2020.03.007)

[Li H, et al. (2021) Targeting RAB for neurodegeneration](https://doi.org/10.1016/j.tips.2021.02.008)

[Chen Y, et al. (2020) RAB as biomarkers](https://doi.org/10.1016/j.neurobiolaging.2020.07.015)

Additional Mechanisms

Axonal Transport

Rab8B contributes to axonal transport through:

Vesicle movement along microtubules
Coordination with motor proteins
Regulation of transport cargo composition

Defects in axonal transport are increasingly recognized as early events in neurodegeneration.

Membrane Recycling

Rab8B plays important roles in:

Synaptic vesicle membrane recycling
Receptor recycling at the plasma membrane
Endosomal recycling pathway regulation

These processes are essential for maintaining synaptic function during sustained activity.

Golgi Function

Rab8B maintains Golgi apparatus integrity through:

Golgi-to-plasma membrane trafficking
Golgi-to-endosome sorting
Golgi cisternal maintenance

Golgi dysfunction is observed in many neurodegenerative conditions.

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Related Entities

RAB8B

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slug	genes-rab8b
kg_node_id	RAB8B
entity_type	gene
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-4ba23c80238b
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'genes-rab8b'}
_schema_version	1

📊 Evidence Profile

Evidence Balance

+0%

Certainty

10%

Debates

0

Incoming

2

Outgoing

5

0 supporting 0 contradicting 0 neutral

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📗 Cite This Artifact

RAB8B

RAB8B

Overview

RAB8B

Overview

Molecular Biology and Function

Protein Structure and GTPase Cycle

Effector Proteins

Tissue Distribution

Role in Neurodegeneration

Parkinson's Disease

Alzheimer's Disease

Ciliary Dysfunction

Therapeutic Implications

Targeting RAB8B Pathway

Challenges

Pathway Interactions

Cross-talk with Other Rab Proteins

Interactions with Neurodegeneration Pathways

Signaling Pathway Interactions

Research Tools and Models

Genetic Models

Cellular Models

Modulators

Key Publications

See Also

External Links

References

Additional Mechanisms

Axonal Transport

Membrane Recycling

Golgi Function

💬 Discussion