WHEP domains direct noncanonical function of glutamyl-Prolyl tRNA synthetase in translational control of gene expression.
The heterotetrameric GAIT complex suppresses translation of selected mRNAs in interferon-gamma-activated monocytic cells. Specificity is dictated by glutamyl-prolyl tRNA synthetase (EPRS) binding to a 3'UTR element in target mRNAs. EPRS consists of two synthetase cores joined by a linker containing three WHEP domains of unknown function. Here we show the critical role of EPRS WHEP domains in targeting and regulating GAIT complex binding to RNA. The upstream WHEP pair directs high-affinity binding to GAIT element-bearing mRNAs, while the overlapping, downstream pair binds NSAP1, which inhibits mRNA binding. Interaction of EPRS with ribosomal protein L13a and GAPDH induces a conformational switch that rescues mRNA binding and restores translational control. Total reconstitution from purified components indicates that the four GAIT proteins are necessary and sufficient for self-assembly of a functional complex. Our results establish the essentiality of WHEP domains in the noncanonical function of EPRS in regulating inflammatory gene expression.
Jia
Jie
J
Department of Cell Biology, The Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
Arif
Abul
A
Ray
Partho S
PS
Fox
Paul L
PL
D020413:3' Untranslated Regions / Q000235:genetics; D000604:Amino Acyl-tRNA Synthetases / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D005786:Gene Expression Regulation; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000201:enzymology; D007700:Kinetics; D046911:Macromolecular Substances / Q000378:metabolism; D009000:Monocytes / Q000201:enzymology; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D000090822:Ribosomal Protein L3; D012269:Ribosomal Proteins / Q000378:metabolism; D014158:Transcription, Genetic
D020413:3' Untranslated Regions; D046911:Macromolecular Substances; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D000090822:Ribosomal Protein L3; D012269:Ribosomal Proteins; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D000604:Amino Acyl-tRNA Synthetases; C415462:glutamyl-prolyl-tRNA synthetase