LAPTM4B Protein

LAPTM4B Protein

Introduction

Laptm4B 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.

--- [@lysosomal2021]
title: LAPTM4B Protein [@autophagy2022]
--- [@laptmb2019]

<div class="infobox infobox-protein"> [@targeting2023]
<table> [@mtor2020]
<tr><th colspan="2" style="background:#f8f9fa; text-align:center;">LAPTM4B Protein</th></tr> [@autophagy2021]
<tr><td><b>Protein Name</b></td><td>Lysosomal-associated transmembrane protein 4 beta</td></tr> [@laptmb2022]
<tr><td><b>Gene</b></td><td>[LAPTM4B](/genes/laptm4b)</td></tr>
<tr><td><b>UniProt ID</b></td><td>[Q9Y5G5](https://www.uniprot.org/uniprot/Q9Y5G5)</td></tr>
<tr><td><b>Chromosomal Location</b></td><td>2q21.1</td></tr>
<tr><td><b>Description</b></td><td>Lysosomal membrane protein with roles in [autophagy](/entities/autophagy), cell proliferation, and cancer</td></tr>
<tr><td><b>Subcellular Localization</b></td><td>Lysosome, plasma membrane</td></tr>
<tr><td><b>Protein Family</b></td><td>LAPTMs (Lysosomal-associated transmembrane proteins)</td></tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
</div>

Overview

LAPTM4B Protein

Introduction

Laptm4B 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.

--- [@lysosomal2021]
title: LAPTM4B Protein [@autophagy2022]
--- [@laptmb2019]

<div class="infobox infobox-protein"> [@targeting2023]
<table> [@mtor2020]
<tr><th colspan="2" style="background:#f8f9fa; text-align:center;">LAPTM4B Protein</th></tr> [@autophagy2021]
<tr><td><b>Protein Name</b></td><td>Lysosomal-associated transmembrane protein 4 beta</td></tr> [@laptmb2022]
<tr><td><b>Gene</b></td><td>[LAPTM4B](/genes/laptm4b)</td></tr>
<tr><td><b>UniProt ID</b></td><td>[Q9Y5G5](https://www.uniprot.org/uniprot/Q9Y5G5)</td></tr>
<tr><td><b>Chromosomal Location</b></td><td>2q21.1</td></tr>
<tr><td><b>Description</b></td><td>Lysosomal membrane protein with roles in [autophagy](/entities/autophagy), cell proliferation, and cancer</td></tr>
<tr><td><b>Subcellular Localization</b></td><td>Lysosome, plasma membrane</td></tr>
<tr><td><b>Protein Family</b></td><td>LAPTMs (Lysosomal-associated transmembrane proteins)</td></tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
</div>

Overview

LAPTM4B (Lysosomal Associated Transmembrane Protein 4 Beta) is a multi-pass membrane protein with important roles in lysosomal function, autophagy, and cell proliferation. It is frequently overexpressed in various cancers and has been studied as both a prognostic biomarker and potential therapeutic target. In the brain, LAPTM4B supports neuronal function and is implicated in neurodegenerative diseases.

Structure

LAPTM4B contains multiple structural features:

• Transmembrane domains: Multiple helices span the lysosomal membrane
• Cytoplasmic N-terminus: Contains sorting and regulatory motifs
• C-terminal domain: Mediates protein-protein interactions

Normal Function

Lysosomal Function

LAPTM4B supports lysosomal homeostasis:

• Membrane trafficking: Facilitates transport to and from lysosomes
• Lysosomal integrity: Maintains lysosomal membrane stability
• Autophagy support: Promotes autophagosome-lysosome fusion

Cell Proliferation

The protein has growth-promoting effects:

• Cell cycle modulation: Affects G1/S transition
• Growth factor signaling: Modulates receptor tyrosine kinase signaling
• Anti-apoptotic functions: Inhibits caspase-dependent [apoptosis](/entities/apoptosis)

Autophagy Regulation

LAPTM4B modulates autophagy:

• [mTOR](/mechanisms/mtor-signaling-pathway) pathway: May affect mTORC1 signaling
• Autophagosome formation: Modulates initiation of autophagy
• Lysosomal function: Supports degradative capacity

Role in Neurodegeneration

Alzheimer's Disease

LAPTM4B contributes to AD pathogenesis:

Parkinson's Disease

In PD, LAPTM4B has complex roles:

Cancer Biology

LAPTM4B is an important oncogenic protein:

• Gene amplification: Frequently amplified in breast, ovarian, liver cancers
• Oncogenic signaling: Activates PI3K/AKT and other pathways
• Prognostic marker: High expression predicts poor survival

Therapeutic Implications

LAPTM4B is a therapeutic target:

• Cancer therapy: siRNA and antibody approaches in development
• Neurodegeneration: Modulation to enhance autophagy
• Biomarker: Serum LAPTM4B as cancer biomarker

See Also

• [LAPTM4B Gene](/genes/laptm4b)
• [Lysosomal Degradation](/mechanisms/lysosomal-degradation)
• [Autophagy Pathway](/mechanisms/autophagy)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)

Background

The study of Laptm4B 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.

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