STAM2 Gene - Signal Transducing Adaptor Molecule 2

STAM2 Gene - Signal Transducing Adaptor Molecule 2

Introduction

[STAM2](/entities/stam2) (Signal Transducing Adaptor Molecule 2) is a key component of the ESCRT-0 complex that plays a critical role in endolysosomal trafficking and protein clearance. Together with STAM1, STAM2 has been identified as a novel Parkinson's disease therapeutic target through multi-omics studies showing that loss-of-function variants contribute to endolysosomal pathway dysfunction and [alpha-synuclein](/proteins/alpha-synuclein) accumulation[@stam1_parkinson_2025].

<div class="infobox infobox-gene">
<h3>STAM2</h3>
<table>
<tr><th>Full Name</th><td>Signal Transducing Adaptor Molecule 2</td></tr>
<tr><th>Gene Symbol</th><td>STAM2</td></tr>
<tr><th>Chromosomal Location</th><td>2q23.3</td></tr>
<tr><th>NCBI Gene ID</th><td>[23176](https://www.ncbi.nlm.nih.gov/gene/23176)</td></tr>
<tr><th>Ensembl ID</th><td>ENSG00000084073</td></tr>
<tr><th>UniProt</th><td>[O75886](https://www.uniprot.org/uniprot/O75886)</td></tr>
<tr><th>Protein Length</th><td>424 amino acids</td></tr>
<tr><th>Associated Diseases</th><td>[Parkinson's Disease](/diseases/parkinsons-disease), [Dementia with Lewy Bodies](/diseases/dementia-with-lewy-bodies)</td></tr>
</table>
</div>

Overview

The STAM2 gene encodes a signal transducing adaptor molecule that functions as a key regulator of endosomal sorting and lysosomal degradation. STAM2 is part of the ESCRT-0 complex (together with STAM1 and HGS), which recognizes and sorts ubiquitinated cargo proteins for delivery to lysosomes[@stam2_structure_2020].

STAM2 Gene - Signal Transducing Adaptor Molecule 2

Introduction

[STAM2](/entities/stam2) (Signal Transducing Adaptor Molecule 2) is a key component of the ESCRT-0 complex that plays a critical role in endolysosomal trafficking and protein clearance. Together with STAM1, STAM2 has been identified as a novel Parkinson's disease therapeutic target through multi-omics studies showing that loss-of-function variants contribute to endolysosomal pathway dysfunction and [alpha-synuclein](/proteins/alpha-synuclein) accumulation[@stam1_parkinson_2025].

<div class="infobox infobox-gene">
<h3>STAM2</h3>
<table>
<tr><th>Full Name</th><td>Signal Transducing Adaptor Molecule 2</td></tr>
<tr><th>Gene Symbol</th><td>STAM2</td></tr>
<tr><th>Chromosomal Location</th><td>2q23.3</td></tr>
<tr><th>NCBI Gene ID</th><td>[23176](https://www.ncbi.nlm.nih.gov/gene/23176)</td></tr>
<tr><th>Ensembl ID</th><td>ENSG00000084073</td></tr>
<tr><th>UniProt</th><td>[O75886](https://www.uniprot.org/uniprot/O75886)</td></tr>
<tr><th>Protein Length</th><td>424 amino acids</td></tr>
<tr><th>Associated Diseases</th><td>[Parkinson's Disease](/diseases/parkinsons-disease), [Dementia with Lewy Bodies](/diseases/dementia-with-lewy-bodies)</td></tr>
</table>
</div>

Overview

The STAM2 gene encodes a signal transducing adaptor molecule that functions as a key regulator of endosomal sorting and lysosomal degradation. STAM2 is part of the ESCRT-0 complex (together with STAM1 and HGS), which recognizes and sorts ubiquitinated cargo proteins for delivery to lysosomes[@stam2_structure_2020].

STAM1 and STAM2 are closely related paralogs that have partially overlapping functions in the endolysosomal pathway. Both proteins contain an SH3 domain that interacts with various signaling proteins, and a ubiquitin-interacting motif (UIM) for cargo recognition.

Structure and Function

STAM2 contains several functional domains:

• UIM (Ubiquitin-Interacting Motif): Binds ubiquitin-tagged cargo proteins
• SH3 Domain: Mediates protein-protein interactions with signaling molecules
• MIT Domain: Interacts with ESCRT-III proteins for cargo sorting

Parkinson's Disease Connection

Multi-Omics Evidence

STAM2, along with STAM1, has been identified as a novel PD therapeutic target through comprehensive multi-omics analysis[@stam1_parkinson_2025]:

• Genetic Findings: Rare loss-of-function variants in STAM1/STAM2 increase PD risk
• Transcriptomic Changes: STAM2 expression is altered in PD substantia nigra
• Proteomic Evidence: STAM2 protein levels correlate with alpha-synuclein burden
• Functional Validation: STAM2 deficiency leads to lysosomal dysfunction and alpha-synuclein accumulation[@stam2_lysosomal_2021]

Mechanism of Pathogenesis

Redundancy with STAM1

STAM1 and STAM2 have partially overlapping functions in the ESCRT-0 complex:

• Both can compensate for each other's loss in some cell types
• Neurons appear particularly vulnerable to combined deficiency
• Single-allele variants may be sufficient to increase PD risk
• Therapeutic targeting may need to address both proteins

Therapeutic Potential

Target Rationale

STAM2 represents an attractive therapeutic target for PD because:

Therapeutic Strategies

| Approach | Mechanism | Development Stage | Reference |
|----------|-----------|-------------------|------------|
| STAM2 overexpression | Restore ESCRT function | Preclinical | [@stam2_lysosomal_2021] |
| STAM1/STAM2 dual targeting | Restore complete ESCRT-0 | Discovery | [@stam1_parkinson_2025] |
| Small molecule enhancers | Boost ESCRT-0 activity | Discovery | - |
| Gene therapy | AAV-mediated delivery | Preclinical | - |
| ESCRT modulators | Upstream pathway activation | Discovery | [@stam_escrts_2019] |

Gene Function Summary

Molecular Functions

• Ubiquitin Binding: Recognizes and binds ubiquitinated cargo proteins
• Adaptor Function: Facilitates protein-protein interactions in ESCRT complex
• Signal Transduction: Couples cargo recognition to downstream sorting events

Biological Processes

• Endosomal protein sorting
• Lysosomal protein degradation
• Autophagosome-lysosome fusion
• Cellular protein quality control
• Neuronal protein homeostasis
• Dopaminergic neuron survival

See Also

• [Parkinson's Disease Pathway](/mechanisms/parkinsons-disease-pathway)
• [Alpha-Synuclein](/proteins/alpha-synuclein)
• [GBA Gene](/genes/gba) - Another PD risk gene in lysosomal pathway
• [STAM1 Gene](/genes/stam1) - Paralog with overlapping function
• [Endolysosomal Pathway](/mechanisms/endolysosomal-pathway-neurodegeneration)
• [ESCRT Complex](/mechanisms/escrts-neurodegeneration)

References

Disease Associations

Source: Open Targets Platform (opentargets.org)

| Disease | Association Score | Disease ID |
|--------|-------------------|------------|
| listeriosis | 0.3696 | EFO_0007347 |
| systemic lupus erythematosus | 0.3000 | MONDO_0007915 |
| Epiphora | 0.2978 | HP_0009926 |
| autoimmune disorder of musculoskeletal system | 0.2899 | MONDO_0000589 |
| food allergy | 0.2297 | EFO_1001890 |