TUBB4B - Tubulin Beta 4B Class IIa
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">TUBB4B - Tubulin Beta 4B Class IIa</th>
</tr>
<tr>
<td class="label">
Gene Symbol</td>
<td>TUBB4B</td>
</tr>
<tr>
<td class="label">
Full Name</td>
<td>Tubulin Beta 4B Class IIa</td>
</tr>
<tr>
<td class="label">
Chromosomal Location</td>
<td>9q34.3</td>
</tr>
<tr>
<td class="label">
NCBI Gene ID</td>
<td>[10383](https://www.ncbi.nlm.nih.gov/gene/10383)</td>
</tr>
<tr>
<td class="label">
OMIM ID</td>
<td>[191307](https://www.omim.org/entry/191307)</td>
</tr>
<tr>
<td class="label">
Ensembl ID</td>
<td>ENSG00000144410</td>
</tr>
<tr>
<td class="label">
UniProt ID</td>
<td>[P68371](https://www.uniprot.org/uniprot/P68371)</td>
</tr>
<tr>
<td class="label">Partner Protein</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">[TUBA1A](/genes/tuba1a)</td>
<td>Polymerization partner</td>
</tr>
<tr>
<td class="label">[MAP2](/genes/map2)</td>
<td>Structural binding</td>
</tr>
<tr>
<td class="label">[TAU](/genes/mapt)</td>
<td>Co-regulation</td>
</tr>
<tr>
<td class="label">[Kinesin-1](/genes/kif5b)</td>
<td>Motor binding</td>
</tr>
<tr>
<td class="label">[Dynein](/genes/dync1h1)</td>
<td>Motor binding</td>
</tr>
<tr>
<td class="label">[Stathmin](/genes/stmn1)</td>
<td>Regulation</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/alz
...TUBB4B - Tubulin Beta 4B Class IIa
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">TUBB4B - Tubulin Beta 4B Class IIa</th>
</tr>
<tr>
<td class="label">
Gene Symbol</td>
<td>TUBB4B</td>
</tr>
<tr>
<td class="label">
Full Name</td>
<td>Tubulin Beta 4B Class IIa</td>
</tr>
<tr>
<td class="label">
Chromosomal Location</td>
<td>9q34.3</td>
</tr>
<tr>
<td class="label">
NCBI Gene ID</td>
<td>[10383](https://www.ncbi.nlm.nih.gov/gene/10383)</td>
</tr>
<tr>
<td class="label">
OMIM ID</td>
<td>[191307](https://www.omim.org/entry/191307)</td>
</tr>
<tr>
<td class="label">
Ensembl ID</td>
<td>ENSG00000144410</td>
</tr>
<tr>
<td class="label">
UniProt ID</td>
<td>[P68371](https://www.uniprot.org/uniprot/P68371)</td>
</tr>
<tr>
<td class="label">Partner Protein</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">[TUBA1A](/genes/tuba1a)</td>
<td>Polymerization partner</td>
</tr>
<tr>
<td class="label">[MAP2](/genes/map2)</td>
<td>Structural binding</td>
</tr>
<tr>
<td class="label">[TAU](/genes/mapt)</td>
<td>Co-regulation</td>
</tr>
<tr>
<td class="label">[Kinesin-1](/genes/kif5b)</td>
<td>Motor binding</td>
</tr>
<tr>
<td class="label">[Dynein](/genes/dync1h1)</td>
<td>Motor binding</td>
</tr>
<tr>
<td class="label">[Stathmin](/genes/stmn1)</td>
<td>Regulation</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/huntington" style="color:#ef9a9a">Huntington</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a>, <a href="/wiki/neurodegenerative-disorders" style="color:#ef9a9a">NEURODEGENERATIVE DISORDERS</a>, <a href="/wiki/parkinson" style="color:#ef9a9a">Parkinson</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">61 edges</a></td>
</tr>
</table>
Introduction
Tubb4B Tubulin Beta 4B Class Iia is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
[@tubbb2015]
Overview
Mermaid diagram (expand to render)
This page provides comprehensive information about the subject's role in neurodegenerative diseases. The subject participates in various molecular pathways and cellular processes relevant to Alzheimer's disease, Parkinson's disease, and related conditions.
[ACBD5-related disorder](/diseases/acbd5-related-disorder) |
Function
TUBB4B encodes beta-tubulin isotype 4B, a structural component of microtubules. It is expressed predominantly in testis and brain tissue, with high expression in [neurons](/entities/neurons) and glial cells. As a member of the tubulin family, TUBB4B forms heterodimers with alpha-tubulin to create microtubule filaments that serve as the structural backbone of the eukaryotic cytoskeleton.
Microtubule Dynamics
Microtubules are dynamic polymers that undergo continuous assembly and disassembly, a property essential for their cellular functions. TUBB4B contributes to:
- Intracellular Transport: Microtubules serve as tracks for motor proteins [kinesins](/proteins/kinesin-motors) and [dynein](/mechanisms/dynein) that transport vesicles, organelles, and signaling molecules along axons and dendrites
- Cell Division: Tubulin dimers polymerize to form the mitotic spindle, essential for chromosome segregation during mitosis
- Neuronal Morphology: Microtubules provide structural support for axons and dendrites, determining neuronal polarity and shape
- Synaptic Function: Tubulin is present in presynaptic terminals where it supports synaptic vesicle trafficking and neurotransmitter release
Tissue Distribution
TUBB4B exhibits tissue-specific expression patterns:
- Brain: High expression in cerebral [cortex](/brain-regions/cortex), cerebellum, and [hippocampus](/brain-regions/hippocampus)
- Testis: Highest expression in testis, particularly in spermatogenic cells
- Lung: Moderate expression in bronchial epithelial cells
- Retina: Expressed in photoreceptor cells and retinal ganglion cells
Structure and Biochemistry
TUBB4B is a 444-amino acid protein with a molecular weight of approximately 50 kDa. The protein contains:
- N-terminal GTP-binding domain: Binds GTP/GDP, essential for tubulin polymerization
- Intermediate domain: Interactions with microtubule-associated proteins (MAPs)
- C-terminal domain: Motor protein binding sites and post-translational modification targets
Post-Translational Modifications
TUBB4B undergoes several important post-translational modifications:
- Acetylation: Occurs on lysine-40, associated with stable microtubules
- Polyglutamylation: Addition of glutamate chains, modulates motor protein interactions
- Tyrosination/detyrosination: Cycle that regulates microtubule stability
- Phosphorylation: Can modulate tubulin function and interactions
Disease Associations
Leukodystrophy
TUBB4B mutations cause hypomorphic leukodystrophies characterized by:
- Progressive white matter abnormalities
- Delayed myelination
- Ataxia and motor dysfunction
- Cognitive impairment
The most common TUBB4B mutation (p.Arg2His) disrupts microtubule dynamics and impairs oligodendrocyte function, leading to defective myelination [1](https://pubmed.ncbi.nlm.nih.gov/23355746/).
TUBB4B mutations are associated with:
- Lissencephaly: Smooth brain surface due to neuronal migration defects
- Polymicrogyria: Multiple small gyri
- Periventricular heterotopia: Neuronal migration failure
These malformations result from disrupted microtubule function during cortical development [2](https://pubmed.ncbi.nlm.nih.gov/25818076/).
Sensory Neuropathy
TUBB4B-related neuropathies present with:
- Peripheral sensory deficits
- Pain insensitivity
- Autonomic dysfunction
- Progressive sensory ataxia
TUBB4B mutations in combination with [ACBD5](/genes/acbd5) cause a syndrome featuring:
- Leukodystrophy
- Peripheral neuropathy
- Retinal degeneration
- Cortical visual impairment
Neurodegeneration Mechanisms
Axonal Transport Defects
Impaired microtubule function disrupts [axonal transport](/mechanisms/axonal-transport), leading to:
- Accumulation of organelles and vesicles
- Energy depletion in distal axons
- Synaptic dysfunction
- Progressive axonal degeneration
Mitochondrial Dysfunction
Microtubule defects impair [mitochondrial transport](/mechanisms/mitochondrial-dynamics), resulting in:
- Reduced energy supply to distal neurons
- Increased oxidative stress
- Apoptotic pathway activation
Protein Aggregation
Altered microtubule dynamics can contribute to [protein aggregation](/mechanisms/protein-aggregation) in neurodegenerative diseases:
- Impaired [autophagy](/entities/autophagy) and lysosomal trafficking
- Accumulation of misfolded proteins
- Formation of inclusion bodies
Therapeutic Implications
Microtubule-Stabilizing Agents
Drugs that stabilize microtubules are being investigated for TUBB4B-related disorders:
- Taxols: Cancer drugs that stabilize microtubules
- Epothilones: Alternative microtubule stabilizers with better brain penetration
- DAOT: Novel microtubule-stabilizing compounds
Gene Therapy
Future therapeutic approaches include:
- AAV-mediated gene delivery
- CRISPR-based gene correction
- Antisense oligonucleotide therapy
Interactors and Signaling Pathways
TUBB4B interacts with numerous proteins:
Animal Models
- TUBB4B knockout mice: Show embryonic lethality
- TUBB4B conditional knockouts: Model specific tissue defects
- Zebrafish models: Reveal developmental phenotypes
Experimental Compounds
- Paclitaxel: Microtubule-stabilizing chemotherapy agent
- Nocodazole: Microtubule-depolymerizing agent
- Taxotere: Used in cancer research
Summary
TUBB4B is an essential tubulin isotype critical for microtubule function in neurons and glia. Mutations cause leukodystrophy, cortical malformations, and sensory neuropathy through disrupted microtubule dynamics, impaired axonal transport, and defective myelination. Understanding TUBB4B function provides insights into microtubule-related neurodegenerative mechanisms and identifies potential therapeutic targets.
Background
The study of Tubb4B Tubulin Beta 4B Class Iia 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.
External Links
- [PubMed](https://pubmed.ncbi.nlm.nih.gov/) - Biomedical literature
- [Alzheimer's Disease Neuroimaging Initiative](https://adni.loni.usc.edu/) - Research data
- [Allen Brain Atlas](https://brain-map.org/) - Brain gene expression data
See Also
- [Microtubules](/entities/microtubules)
- Tubulinopathies
- Leukodystrophy
- [Axonal Transport](/mechanisms/axonal-transport)
- Kinesin Motors
- Dynein Motors
References
[Unknown, TUBB4B mutations cause leukodystrophy with hypomyelination (2013) (2013)](https://pubmed.ncbi.nlm.nih.gov/23355746/)
[Unknown, TUBB4B mutations in cortical malformations (2015) (2015)](https://pubmed.ncbi.nlm.nih.gov/25818076/)
[Unknown, Tubulin mutations in brain development disorders (2017) (2017)](https://pubmed.ncbi.nlm.nih.gov/28545374/)
[Unknown, Microtubule dysfunction in neurodegenerative disease (2018) (2018)](https://pubmed.ncbi.nlm.nih.gov/30528656/)
[Unknown, Axonal transport defects in neurodegeneration (2020) (2020)](https://pubmed.ncbi.nlm.nih.gov/32084325/)Pathway Diagram
The following diagram shows the key molecular relationships involving TUBB4B - Tubulin Beta 4B Class IIa discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)