TUBB4B - Tubulin Beta 4B Class IIa

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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

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/).

Cortical Malformations

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

ACBD5-Related Disorder

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:

Research Tools

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

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)

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TUBB4B - Tubulin Beta 4B Class IIa

TUBB4B - Tubulin Beta 4B Class IIa

TUBB4B - Tubulin Beta 4B Class IIa

Introduction

Overview

Function

Microtubule Dynamics

Tissue Distribution

Structure and Biochemistry

Post-Translational Modifications

Disease Associations

Leukodystrophy

Cortical Malformations

Sensory Neuropathy

ACBD5-Related Disorder

Neurodegeneration Mechanisms

Axonal Transport Defects

Mitochondrial Dysfunction

Protein Aggregation

Therapeutic Implications

Microtubule-Stabilizing Agents

Gene Therapy

Interactors and Signaling Pathways

Research Tools

Animal Models

Experimental Compounds

Summary

Background

External Links

See Also

References

Pathway Diagram