EIF2S3B (Eukaryotic Translation Initiation Factor 2 Subunit Gamma, B)
A testis-specific isoform of the gamma subunit of eukaryotic initiation factor 2, involved in translation initiation and linked to intellectual disability and microcephaly.
Gene Information Card
| Symbol | EIF2S3B |
|---|---|
| Full Name | Eukaryotic translation initiation factor 2 subunit gamma, B |
| Gene Type | protein-coding |
| Chromosomal Location | Xp22.11 |
| NCBI Gene ID | 1967 ncbi.nlm.nih.gov/gene/1967 |
| Ensembl ID | ENSG00000285348 |
| UniProt ID | P41091 |
| OMIM ID | 300161 |
| HGNC ID | 3261 |
| Aliases | eIF-2gamma, eIF2gamma, EIF2S3 |
Description
EIF2S3B encodes a testis-specific isoform of the gamma subunit of eukaryotic translation initiation factor 2 (eIF2). This protein is part of the eIF2 complex that delivers initiator tRNA to the ribosome during translation initiation. The B isoform is highly similar to the ubiquitous EIF2S3 isoform but is predominantly expressed in the testis. Mutations in EIF2S3B have been associated with X-linked intellectual disability and microcephaly.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| X-linked intellectual disability | Loss-of-function mutations impair translation initiation, affecting neuronal development. | ClinVar, OMIM |
| Microcephaly | Reduced eIF2 activity leads to impaired cell proliferation and brain growth. | ClinVar, OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | High | High |
| Other tissues | Low/Not detected | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Testicular cell lines | High | Testis-specific expression |
| HeLa | Low | Low expression |
| HEK293 | Low | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1046G>A (p.Arg349His) | Missense | Rare | Impaired eIF2 complex formation |
| c.1189C>T (p.Arg397Trp) | Missense | Rare | Reduced translation initiation |
| c.1A>G (p.Met1Val) | Start loss | Rare | Loss of protein function |
Mutation functional classification
Loss of Function (LOF)
Mutations that reduce eIF2 activity or stability lead to haploinsufficiency, causing neurodevelopmental phenotypes.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
Some missense mutations may act in a dominant-negative manner by disrupting the eIF2 complex.
View complete mutation data：
Gene Ontology (GO)
| • translation initiation factor activity | • GTP binding |
| • ribosome binding | • cytoplasm |
| • eIF2 complex |
Pathways
• Eukaryotic translation initiation
• Regulation of eIF2 activity by phosphorylation
Protein Summary
The EIF2S3B protein is a 472-amino acid gamma subunit of eIF2, sharing high homology with the ubiquitous EIF2S3 isoform. It contains a GTP-binding domain and interacts with alpha and beta subunits to form the eIF2 complex. The testis-specific expression suggests a specialized role in spermatogenesis, but mutations also affect neuronal function, indicating a broader requirement in development.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| EIF2S3B Knockout HEK293 Cell Line | EDJ-KQ11793 | Human | 255308 | Details Get a Quote |
| EIF2S3B Knockout A-549 Cell Line | EDJ-KQ40201 | Human | 255308 | Details Get a Quote |
| EIF2S3B Knockout HCT 116 Cell Line | EDJ-KQ40202 | Human | 255308 | Details Get a Quote |
| EIF2S3B Knockout HeLa Cell Line | EDJ-KQ40203 | Human | 255308 | Details Get a Quote |
