eIF-2-alpha kinase GCN2 - P15442 (GCN2_YEAST)

 

Protein Feature View of PDB entries mapped to a UniProtKB sequence  

  • Number of PDB entries for P15442: 7
 
Function
Metabolic-stress sensing protein kinase that phosphorylates the alpha subunit of eukaryotic translation initiation factor 2 (eIF-2-alpha/SUI2) on 'Ser-52' in response to low amino acid availability (PubMed:1739968, PubMed:7623840, PubMed:8798780, PubMed:9528799, PubMed:10983975, PubMed:17202131). Plays a role as an activator of the general amino acid control (GAAC) pathway required for adapatation to amino acid starvation. Converts phosphorylated eIF-2-alpha/SUI2 either to a competitive inhibitor of translation initiation factor eIF-2B, leading to a global protein synthesis repression, and thus to a reduced overall utilization of amino acids, or to a translational initiation activation of specific mRNAs, such as the transcriptional activator GCN4, and hence allowing GCN4-mediated reprogramming of amino acid biosynthetic gene expression to alleviate nutrient depletion (PubMed:2660141, PubMed:2188100, PubMed:1739968, PubMed:7621831, PubMed:7623840, PubMed:8798780, PubMed:10801780, PubMed:11350982, PubMed:24333428). Binds uncharged tRNAs (PubMed:7623840, PubMed:10983975). UniProt
Catalytic Activity
ATP + a protein = ADP + a phosphoprotein. UniProt
Pathway Maps
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Subunit Structure
Homodimer; homodimerization is important for kinase activation by uncharged tRNAs (PubMed:9566889, PubMed:10983975, PubMed:11250908, PubMed:17202131, PubMed:15964839). Interacts (via N-terminal RWD domain) with GCN1 (via N- and C-terminus); this interaction stimulates GCN2 kinase activity in a GCN20-dependent manner in response to amino acid starvation (PubMed:10775272, PubMed:11101534, PubMed:10801780, PubMed:11350982, PubMed:21849502). Interacts (via N-terminus) with the GCN1-GCN20 complex on translating ribosomes in amino acid-starved cells; GCN1 may bind near the ribosomal A-site and promotes the transfer of uncharged tRNAs from the A-site to the tRNA-binding domain in GCN2 for its subsequent kinase activation, and hence allowing GCN4 translational activation and derepression of amino acid biosynthetic genes (PubMed:10775272, PubMed:11101534). Interacts (via C-terminus) with TIF11; this interaction is direct, occurs in amino acid-repleted cells, may be stabilzed in a ribosome-dependent manner, reduces GCN2-mediated eIF-2-alpha phosphorylation but not GCN2 autophosphorylation and is lost in amino acid-starved cells and by uncharged tRNAs (PubMed:21849502). Associates (via C-terminus) with ribosomes (PubMed:2038314, PubMed:9430731, PubMed:10983975, PubMed:22888004). UniProt
Domain
The C-terminal domain negatively regulates kinase activity via an autoinhibitory association with the protein kinase and histidyl-tRNA synthetase-like domains in amino acid-repleted cells, that is counteracted by uncharged tRNAs in amino acid-starved cells (PubMed:7623840, PubMed:8798780, PubMed:10983975, PubMed:11250908). The C-terminal, histidyl-tRNA synthetase-like region and protein kinase domains are necessary for homodimer formation (PubMed:9566889, PubMed:10983975, PubMed:11250908). The C-terminal and protein kinase domains are necessary for ribosome association (PubMed:9566889, PubMed:10983975). The C-terminal and histidyl-tRNA synthetase-like regions are required for uncharged tRNAs binding in amino acid-starved cells (PubMed:7623840, PubMed:8798780, PubMed:9430731, PubMed:10983975). UniProt
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Data in green originates from UniProtKB  
Variation data (sourced from UniProt) shows non-genetic variation from the ExPASy   and dbSNP   websites.
Data in yellow originates from Pfam  , by interacting with the HMMER3 web site  
Data in purple originates from Phosphosite  .
Data in orange originates from the SCOP   (version 1.75) and SCOPe   (version 2.04) classifications.
Data in grey has been calculated using BioJava  . Protein disorder predictions are based on JRONN (Troshin, P. and Barton, G. J. unpublished), a Java implementation of RONN  
  • Red: potentially disorderd region
  • Blue: probably ordered region.
Hydropathy has been calculated using a sliding window of 15 residues and summing up scores from standard hydrophobicity tables.
  • Red: hydrophobic
  • Blue: hydrophilic.
Data in lilac represent the genomic exon structure projected onto the UniProt sequence.
Data in blue originates from PDB
  • Secstruc: Secondary structure projected from representative PDB entries onto the UniProt sequence.
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Validation Track

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The PDB to UniProt mapping is based on the data provided by the EBI SIFTS project. See also Velankar et al., Nucleic Acids Research 33, D262-265 (2005).
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