Ubiquilin-4 Protein

Ubiquilin-4 Protein

Introduction

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">Ubiquilin-4 Protein</th>
</tr>
<tr>
<td class="label">Target</td>
<td>Approach</td>
</tr>
<tr>
<td class="label">UBQLN4 expression</td>
<td>Gene therapy</td>
</tr>
<tr>
<td class="label">Proteasome enhancement</td>
<td>Small molecules</td>
</tr>
<tr>
<td class="label">Protein aggregate clearance</td>
<td>Immunotherapy</td>
</tr>
</table>

Ubiquilin 4 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.

Overview

Ubiquilin-4 (UBQLN4) is a member of the ubiquilin family of proteins that function as ubiquitin receptors in protein quality control pathways. It plays a critical role in targeting ubiquitinated proteins to the proteasome for degradation. [@edens2017]

Protein Information

• Gene Symbol: UBQLN4
• Protein Name: Ubiquilin-4
• Molecular Weight: ~66 kDa
• Aliases: UBIN, PROTI, Chap1

Structure

UBQLN4 contains multiple functional domains: [@bertram2005]

• N-terminal ubiquitin-like (Ubl) domain - interacts with proteasome
• Central STI (S/T-rich) domains - protein-protein interactions
• C-terminal ubiquitin-associated (UBA) domain - binds ubiquitin chains

...

Ubiquilin-4 Protein

Introduction

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">Ubiquilin-4 Protein</th>
</tr>
<tr>
<td class="label">Target</td>
<td>Approach</td>
</tr>
<tr>
<td class="label">UBQLN4 expression</td>
<td>Gene therapy</td>
</tr>
<tr>
<td class="label">Proteasome enhancement</td>
<td>Small molecules</td>
</tr>
<tr>
<td class="label">Protein aggregate clearance</td>
<td>Immunotherapy</td>
</tr>
</table>

Ubiquilin 4 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.

Overview

Ubiquilin-4 (UBQLN4) is a member of the ubiquilin family of proteins that function as ubiquitin receptors in protein quality control pathways. It plays a critical role in targeting ubiquitinated proteins to the proteasome for degradation. [@edens2017]

Protein Information

• Gene Symbol: UBQLN4
• Protein Name: Ubiquilin-4
• Molecular Weight: ~66 kDa
• Aliases: UBIN, PROTI, Chap1

Structure

UBQLN4 contains multiple functional domains: [@bertram2005]

• N-terminal ubiquitin-like (Ubl) domain - interacts with proteasome
• Central STI (S/T-rich) domains - protein-protein interactions
• C-terminal ubiquitin-associated (UBA) domain - binds ubiquitin chains

Molecular Function

• Ubiquitin Receptor: Binds polyubiquitinated proteins for proteasomal degradation
• [Autophagy](/entities/autophagy) Receptor: Participates in selective autophagy
• ERAD Component: Involved in endoplasmic reticulum-associated degradation
• Chaperone Activity: Helps prevent protein aggregation

Disease Implications

• ALS-FTD: UBQLN4 mutations cause autosomal dominant ALS with frontotemporal dementia
• IBMPFD: Inclusion body myopathy with early-onset Paget disease and FTD
• Alzheimer's Disease: Altered expression and aggregation in AD brain

Therapeutic Targeting

• Proteostasis modulators
• Autophagy enhancers
• Small molecules to restore protein quality control
• Gene therapy approaches

See Also

• [UBQLN4 Gene](/ubqln4-gene)
• [ALS](/diseases/amyotrophic-lateral-sclerosis)
• [Frontotemporal Dementia](/diseases/frontotemporal-dementia)
• [Protein Quality Control](/mechanisms/protein-quality-control-network)mechanisms/protein-quality-control-network)

Background

The study of Ubiquilin 4 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. [^4]

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions. [^5]

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

Molecular Mechanisms

Ubiquitin-Proteasome System

Ubiquilin-4 (UBQLN4) plays a critical role in the ubiquitin-proteasome system (UPS):

• Acts as a shuttle factor delivering ubiquitinated substrates to the proteasome
• Contains an N-terminal ubiquitin-like (Ubl) domain that interacts with proteasomal subunits
• C-terminal ubiquitin-associated (UBA) domain recognizes polyubiquitin chains
• Facilitates degradation of misfolded, damaged, or regulatory proteins

Protein Quality Control

UBQLN4 participates in cellular protein quality control:

• Targets aggregation-prone proteins for degradation
• Prevents toxic protein aggregate formation
• Helps clear oxidative stress-damaged proteins
• Supports neuronal survival under proteotoxic stress

Disease Associations

Alzheimer's Disease

• UBQLN4 colocalizes with amyloid plaques and neurofibrillary tangles
• Genetic variants associated with AD risk
• Implicated in tau degradation pathways
• May influence Aβ-induced neurotoxicity

Amyotrophic Lateral Sclerosis (ALS)

• UBQLN4 mutations cause familial ALS
• Dysregulated proteostasis in motor neurons
• Interaction with SOD1 and TDP-43 pathology
• Therapeutic target for UPS enhancement

Cancer

• UBQLN4 overexpression in multiple cancers
• Role in DNA damage response
• Prognostic biomarker for poor survival
• Target for anticancer therapy

Therapeutic Implications

Research Directions

• Understanding UBQLN4 substrate specificity
• Developing small molecule modulators
• Gene therapy approaches for UBQLN4 deficiency
• Biomarker development using UBQLN4 levels

References