TUBB4B Protein

TUBB4B Protein

Introduction

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">TUBB4B Protein</th>
</tr>
<tr>
<td class="label">Protein Name</td>
<td>Tubulin Beta 4B Class IIa</td>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>[TUBB4B](/genes/tubb4b)</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>[P68371](https://www.uniprot.org/uniprot/P68371)</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~55 kDa</td>
</tr>
<tr>
<td class="label">Subcellular Localization</td>
<td>Cytoplasm, Cytoskeleton, Neuronal axons</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>Beta-tubulin family</td>
</tr>
<tr>
<td class="label">Expression</td>
<td>Brain (high), retina, testis, lung</td>
</tr>
<tr>
<td class="label">Partner</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">[TUBB3](/proteins/tubb3-protein)</td>
<td>Heterodimer</td>
</tr>
<tr>
<td class="label">Kinesin-1</td>
<td>Motor protein</td>
</tr>
<tr>
<td class="label">Dynein</td>
<td>Motor protein</td>
</tr>
<tr>
<td class="label">Tau (MAPT)</td>
<td>Binding partner</td>
</tr>
<tr>
<td class="label">MAP1B</td>
<td>Binding partner</td>
</tr>
<tr>
<td class="label">Stathmin</td>
<td>Regulatory</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/huntington" style="c

TUBB4B Protein

Introduction

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">TUBB4B Protein</th>
</tr>
<tr>
<td class="label">Protein Name</td>
<td>Tubulin Beta 4B Class IIa</td>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>[TUBB4B](/genes/tubb4b)</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>[P68371](https://www.uniprot.org/uniprot/P68371)</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~55 kDa</td>
</tr>
<tr>
<td class="label">Subcellular Localization</td>
<td>Cytoplasm, Cytoskeleton, Neuronal axons</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>Beta-tubulin family</td>
</tr>
<tr>
<td class="label">Expression</td>
<td>Brain (high), retina, testis, lung</td>
</tr>
<tr>
<td class="label">Partner</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">[TUBB3](/proteins/tubb3-protein)</td>
<td>Heterodimer</td>
</tr>
<tr>
<td class="label">Kinesin-1</td>
<td>Motor protein</td>
</tr>
<tr>
<td class="label">Dynein</td>
<td>Motor protein</td>
</tr>
<tr>
<td class="label">Tau (MAPT)</td>
<td>Binding partner</td>
</tr>
<tr>
<td class="label">MAP1B</td>
<td>Binding partner</td>
</tr>
<tr>
<td class="label">Stathmin</td>
<td>Regulatory</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>

Tubb4B Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

[@betatubulin2016]

Overview

TUBB4B (Tubulin Beta 4B Class IIa) is a member of the beta-tubulin protein family that functions as a fundamental structural component of microtubules. Microtubules are essential cytoskeletal elements involved in cell division, intracellular transport, neuronal morphology, and synaptic function. TUBB4B is particularly important in the nervous system, where it contributes to axonal transport, dendritic arborization, and maintaining neuronal polarity.

Structure

The TUBB4B protein consists of approximately 444 amino acids and contains several functional domains:

• N-terminal domain (1-206 aa): Contains the GTP-binding site and mediates heterodimer formation with alpha-tubulin
• Intermediate domain (207-384 aa): Involved in microtubule polymerization and stability
• C-terminal domain (385-444 aa): Contains the H1-S2 loop and M-loop involved in microtubule binding and motor protein interactions

Normal Function

Microtubule Dynamics

TUBB4B participates in the dynamic instability of microtubules, a process where microtubules continuously alternate between phases of growth and shrinkage. This dynamic behavior is essential for:

• Cell division: Proper chromosome segregation during mitosis
• Intracellular transport: Facilitating vesicle and organelle movement along axons via motor proteins (kinesins and dyneins)
• Neuronal morphology: Maintaining axonal and dendritic architecture
• Synaptic function: Regulating presynaptic vesicle pools and neurotransmitter release

Brain Expression

In the brain, TUBB4B is expressed in [neurons](/entities/neurons) and glial cells, with highest expression in the [cortex](/brain-regions/cortex), [hippocampus](/brain-regions/hippocampus), and cerebellum. It is particularly enriched in axons, where it supports long-range transport between the cell body and synaptic terminals.

Role in Neurodegenerative Diseases

Alzheimer's Disease (AD)

TUBB4B may contribute to Alzheimer's disease pathogenesis through several mechanisms:

• Microtubule destabilization: [Tau protein](/proteins/tau) hyperphosphorylation disrupts microtubule integrity. TUBB4B-containing microtubules may be particularly vulnerable to tau-mediated disruption
• Axonal transport deficits: Impaired transport of [APP](/entities/app-protein), [BACE1](/entities/bace1), and synaptic vesicles along microtubules contributes to amyloidogenic processing
• Neuronal polarity loss: Microtubule destabilization affects axonal maintenance and leads to dendritic sprouting

Parkinson's Disease (PD)

• Alpha-synuclein interaction: Microtubule dysfunction may enhance alpha-synuclein aggregation
• Axonal degeneration: Reduced microtubule stability contributes to dopaminergic neuron axonal loss in the striatum
• Mitochondrial transport: Impaired transport of mitochondria along microtubules affects neuronal bioenergetics

Other Neurodegenerative Conditions

• Amyotrophic Lateral Sclerosis (ALS): Microtubule dysfunction contributes to motor neuron degeneration
• Huntington's Disease (HD): Impaired microtubule-based transport affects mutant [huntingtin](/proteins/huntingtin) clearance
• Charcot-Marie-Tooth Disease (CMT): TUBB4B mutations can cause peripheral neuropathy

Therapeutic Implications

Microtubule-Stabilizing Agents

Drugs that stabilize microtubules (e.g., taxanes, epothilones) are being investigated for neurodegenerative diseases:

• Paclitaxel: Being explored for AD and peripheral neuropathy
• Epothilone D: Shows promise in mouse models of AD
• Davunetide: A microtubule-stabilizing peptide in clinical trials

Drug Targets

• Kinesin modulators: Enhancing anterograde axonal transport
• Dynein inhibitors: Reducing retrograde stress signaling
• Tubulin acetylation promoters: Improving microtubule function

Interactions

TUBB4B interacts with numerous proteins:

See Also

• [TUBB4B Gene](/genes/tubb4b)
• [Microtubule](/mechanisms/cytoskeleton)
• [Axonal Transport](/mechanisms/axonal-transport)
• [Tau Protein](/proteins/tau)
• [Alpha-Synuclein](/proteins/alpha-synuclein)
• [Cytoskeleton Mechanisms](/mechanisms/cytoskeleton-dynamics)

External Links

• [UniProt P68371](https://www.uniprot.org/uniprot/P68371)
• [NCBI Gene: TUBB4B](https://www.ncbi.nlm.nih.gov/gene/10382)
• [Human Protein Atlas: TUBB4B](https://www.proteinatlas.org/ENSG00000104833-TUBB4B)

Background

The study of Tubb4B Protein 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.

References