| EMAP |
|---|
| Gene | [EMAP](/genes/emap) |
| UniProt ID | P40989 |
| Molecular Weight | 68 kDa |
| Subcellular Localization | Cytoplasm, stress granules |
| Protein Family | EMAP family / Translation factor family |
| Brain Expression | High in [neurons](/entities/neurons) |
EMAP (EMAP-Like 1, also known as Eukaryotic Translation Elongation Factor 1 Gamma-like) is a cytosolic protein originally characterized as a tumor antigen but increasingly recognized for its role in RNA metabolism and stress granule dynamics. In the nervous system, EMAP participates in RNA granule assembly and has been implicated in amyotrophic lateral sclerosis (ALS) and other neurodegenerative disorders characterized by RNA granule pathology .
EMAP possesses several functional domains:
- S1 Domain: RNA-binding capability
- Hinge Region: Flexible linker between domains
- Multiple WD-Repeat Regions: Protein-protein interaction surfaces
- Nuclear Localization Signals: Can shuttle between cytoplasm and nucleus
The protein forms homodimers and can multimerize, enabling the formation of larger RNA granule complexes .
EMAP is structurally related to translation elongation factors:
- Associates with the eukaryotic translation elongation factor 1 complex
- May participate in translational control
- Regulates protein synthesis during stress
Under cellular stress, EMAP localizes to stress granules:
- Stress Response: Assembly of stress granules as translational checkpoints
- mRNA Sequestration: Temporarily stores mRNAs not being translated
- Prosurvival Signaling: Stress granules communicate stress to the translation machinery
- Pre-mRNA splicing factors may associate with EMAP
- mRNA export and localization
- RNA stability regulation
EMAP has been reported to:
- Associate with microtubules
- Influence cell division
- Modulate cell motility
ALS is characterized by dysregulated stress granule dynamics, and EMAP is involved:
- Persistent Stress Granules: In ALS models, stress granules become persistent rather than transient
- Sequestration of TDP-43: EMAP-containing granules sequester TDP-43, a hallmark of ALS pathology
- Fusion with Autophagosomes: Abnormal fusion of stress granules with lysosomes
- TDP-43 (encoded by TARDBP) mislocalizes from nucleus to cytoplasm in 97% of ALS cases
- EMAP stress granules may nucleate TDP-43 aggregation
- The C-terminal glycine-rich region of TDP-43 drives aggregation
- Impaired stress response
- Failure to clear damaged proteins
- Dysregulated translation
- Persistent stress granules become toxic
- Sequestration of essential proteins
- Impaired autophagy
- EMAP variants have been associated with ALS risk
- Gene expression studies show altered EMAP in ALS spinal cord
- May modify disease progression
EMAP has been implicated in Alzheimer's disease:
- Tau Pathology: EMAP may interact with tau protein aggregation
- Stress Response: Chronic stress contributes to AD pathogenesis
- RNA Metabolism: Dysregulated RNA processing in AD neurons
- EMAP pathology overlaps with FTD
- TDP-43 positive inclusions in FTD contain stress granule proteins
- EMAP may represent a therapeutic target
Key protein interactions include:
- TDP-43 (TARDBP): RNA-binding protein
- FUS: Fused in sarcoma protein
- TIA-1: Stress granule assembly factor
- G3BP1: Ras-GAP SH3-domain binding protein
- Translation factors: eEF1A, eEF1B
EMAP represents a potential therapeutic target:
- Modulating Stress Granule Dynamics: Compounds that prevent persistent stress granule formation
- Enhancing Autophagy: Clearing pathological stress granules
- RNA-Based Therapies: Targeting EMAP mRNA
EMAP is a stress granule-associated protein that plays important roles in RNA metabolism and cellular stress responses. Its involvement in ALS pathogenesis through TDP-43 pathology makes it a relevant protein for understanding neurodegeneration. The stress granule axis offers therapeutic opportunities for intervention.