6bqi
Structure of two-domain translational regulator Yih1 reveals a possible mechanism of action
Structural highlights
FunctionYIH1_YEAST Translational regulator that ensures constant high levels of translation under amino acid starvation. Plays a role as a negative regulator of the GCN2 kinase activity; impairs GCN1-mediated GCN2 activation, and hence GCN2-mediated eIF-2-alpha phosphorylation in amino acid-starved cells and subsequent down-regulation of protein synthesis (PubMed:15126500, PubMed:15937339, PubMed:24333428). In normal conditions, it resides in a actin complex and has no activity (PubMed:15126500).[1] [2] [3] Publication Abstract from PubMedYeast impact homolog 1 (Yih1), or IMPACT in mammals, is part of a conserved regulatory module controlling the activity of General Control Nonderepressible 2 (Gcn2), a protein kinase that regulates protein synthesis. Yih1/IMPACT is implicated not only in many essential cellular processes, such as neuronal development, immune system regulation and the cell cycle, but also in cancer. Gcn2 must bind to Gcn1 in order to impair the initiation of protein translation. Yih1 hinders this key Gcn1-Gcn2 interaction by binding to Gcn1, thus preventing Gcn2-mediated inhibition of protein synthesis. Here, we solved the structures of the two domains of Saccharomyces cerevisiae Yih1 separately using Nuclear Magnetic Resonance and determined the relative positions of the two domains using a range of biophysical methods. Our findings support a compact structural model of Yih1 in which the residues required for Gcn1 binding are buried in the interface. This model strongly implies that Yih1 undergoes a large conformational rearrangement from a latent closed state to a primed open state to bind Gcn1. Our study provides structural insight into the interactions of Yih1 with partner molecules. Experimentally based structural model of Yih1 provides insight into its function in controlling the key translational regulator Gcn2.,Harjes E, Jameson GB, Tu YH, Burr N, Loo TS, Goroncy AK, Edwards PJB, Harjes S, Munro B, Gobl C, Sattlegger E, Norris GE FEBS Lett. 2021 Feb;595(3):324-340. doi: 10.1002/1873-3468.13990. Epub 2020 Nov, 22. PMID:33156522[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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