Crystal structures of GCN2 protein kinase C-terminal domains suggest regulatory differences in yeast and mammals.
In response to amino acid starvation, GCN2 phosphorylation of eIF2 leads to repression of general translation and initiation of gene reprogramming that facilitates adaptation to nutrient stress. GCN2 is a multidomain protein with key regulatory domains that directly monitor uncharged tRNAs which accumulate during nutrient limitation, leading to activation of this eIF2 kinase and translational control. A critical feature of regulation of this stress response kinase is its C-terminal domain (CTD). Here, we present high resolution crystal structures of murine and yeast CTDs, which guide a functional analysis of the mammalian GCN2. Despite low sequence identity, both yeast and mammalian CTDs share a core subunit structure and an unusual interdigitated dimeric form, albeit with significant differences. Disruption of the dimeric form of murine CTD led to loss of translational control by GCN2, suggesting that dimerization is critical for function as is true for yeast GCN2. However, although both CTDs bind single- and double-stranded RNA, murine GCN2 does not appear to stably associate with the ribosome, whereas yeast GCN2 does. This finding suggests that there are key regulatory differences between yeast and mammalian CTDs, which is consistent with structural differences.
From the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine and.
Hongzhen
H
He
From the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine and.
Isha
I
Singh
From the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine and.
Sheree A
SA
Wek
From the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine and.
Souvik
S
Dey
From the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine and.
Thomas D
TD
Baird
From the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine and rwek@iu.edu.
Ronald C
RC
Wek
From the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine and Department of Chemistry and Chemical Biology, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana 46202 mgeorgia@iu.edu.
Millie M
MM
Georgiadis
D000818:Animals; D002478:Cells, Cultured; D003460:Crystallization; D018360:Crystallography, X-Ray; D004622:Embryo, Mammalian / Q000166:cytology; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D015151:Immunoblotting; D051379:Mice; D018345:Mice, Knockout; D008958:Models, Molecular; D009154:Mutation; D011485:Protein Binding; D014176:Protein Biosynthesis / Q000235:genetics; D055503:Protein Multimerization; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012313:RNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D029701:Saccharomyces cerevisiae Proteins; D012313:RNA; C070634:Eif2ak4 protein, mouse; C512912:GCN2 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases
C-terminal Domain; Crystal Structure; GCN2; Protein Domains; Protein-Nucleic Acid Interaction; Stress; Translation Regulation; eIF2 Kinase