title: The interaction between eukaryotic initiation factor 1A and eIF5 retains eIF1 within scanning preinitiation complexes.
abstract: Scanning of the mRNA transcript by the preinitiation complex (PIC) requires a panel of eukaryotic initiation factors, which includes eIF1 and eIF1A, the main transducers of stringent AUG selection. eIF1A plays an important role in start codon recognition; however, its molecular contacts with eIF5 are unknown. Using nuclear magnetic resonance, we unveil eIF1A's binding surface on the carboxyl-terminal domain of eIF5 (eIF5-CTD). We validated this interaction by observing that eIF1A does not bind to an eIF5-CTD mutant, altering the revealed eIF1A interaction site. We also found that the interaction between eIF1A and eIF5-CTD is conserved between humans and yeast. Using glutathione S-transferase pull-down assays of purified proteins, we showed that the N-terminal tail (NTT) of eIF1A mediates the interaction with eIF5-CTD and eIF1. Genetic evidence indicates that overexpressing eIF1 or eIF5 suppresses the slow growth phenotype of eIF1A-NTT mutants. These results suggest that the eIF1A-eIF5-CTD interaction during scanning PICs contributes to the maintenance of eIF1 within the open PIC.
authors: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School , Boston, Massachusetts 02115, United States.
authors: Rafael E
authors: RE
authors: Luna
authors: Haribabu
authors: H
authors: Arthanari
authors: Hiroyuki
authors: H
authors: Hiraishi
authors: Barak
authors: B
authors: Akabayov
authors: Leiming
authors: L
authors: Tang
authors: Christian
authors: C
authors: Cox
authors: Michelle A
authors: MA
authors: Markus
authors: Lunet E
authors: LE
authors: Luna
authors: Yuka
authors: Y
authors: Ikeda
authors: Ryosuke
authors: R
authors: Watanabe
authors: Edward
authors: E
authors: Bedoya
authors: Cathy
authors: C
authors: Yu
authors: Shums
authors: S
authors: Alikhan
authors: Gerhard
authors: G
authors: Wagner
authors: Katsura
authors: K
authors: Asano
mesh_terms: D000595:Amino Acid Sequence; D015977:Eukaryotic Initiation Factor-1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010448:Peptide Initiation Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D014176:Protein Biosynthesis; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D000097574:Eukaryotic Translation Initiation Factor 5A
chemical_list: D015977:Eukaryotic Initiation Factor-1; D010448:Peptide Initiation Factors; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D000097574:Eukaryotic Translation Initiation Factor 5A; C026022:eukaryotic peptide initiation factor-1A