GCN1
Domain
The RWDBD (RWD-binding domain) region mediates binding to RWD domain-containing proteins, such as EIF2AK4/GCN2, IMPACT and RNF14.
Function
Ribosome collision sensor that plays a key role in the RNF14-RNF25 translation quality control pathway, a pathway that takes place when a ribosome has stalled during translation, and which promotes ubiquitination and degradation of translation factors on stalled ribosomes (PubMed:32610081, PubMed:36638793, PubMed:37651229, PubMed:37951215, PubMed:37951216). Directly binds to the ribosome and acts as a sentinel for colliding ribosomes: activated following ribosome stalling and promotes recruitment of RNF14, which directly ubiquitinates EEF1A1/eEF1A, leading to its degradation (PubMed:36638793, PubMed:37951215, PubMed:37951216). In addition to EEF1A1/eEF1A, the RNF14-RNF25 translation quality control pathway mediates degradation of ETF1/eRF1 and ubiquitination of ribosomal protein (PubMed:36638793, PubMed:37651229). GCN1 also acts as a positive activator of the integrated stress response (ISR) by mediating activation of EIF2AK4/GCN2 in response to amino acid starvation (By similarity). Interaction with EIF2AK4/GCN2 on translating ribosomes stimulates EIF2AK4/GCN2 kinase activity, leading to phosphorylation of eukaryotic translation initiation factor 2 (eIF-2-alpha/EIF2S1) (By similarity). EIF2S1/eIF-2-alpha phosphorylation converts EIF2S1/eIF-2-alpha into a global protein synthesis inhibitor, leading to a global attenuation of cap-dependent translation, and thus to a reduced overall utilization of amino acids, while concomitantly initiating the preferential translation of ISR-specific mRNAs, such as the transcriptional activator ATF4, and hence allowing ATF4-mediated reprogramming of amino acid biosynthetic gene expression to alleviate nutrient depletion (By similarity).
Sequence Similarities
Belongs to the GCN1 family.
Tissue Specificity
Ubiquitously expressed (PubMed:9039502). Expressed in skeletal muscules, ovary and testis (PubMed:9234705).
Cellular localization
- Cytoplasm
- Associates with ribosomes in undifferentiated neuroblastoma cells and increases after neuronal differentiation.
Alternative names
GCN1L1, KIAA0219, GCN1, Stalled ribosome sensor GCN1, GCN1 eIF-2-alpha kinase activator homolog, GCN1-like protein 1, General control of amino-acid synthesis 1-like protein 1, Translational activator GCN1, HsGCN1