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Mapping eIF5A binding sites for Dys1 and Lia1: in vivo evidence for regulation of eIF5A hypusination
Author(s) -
Thompson Gloria M,
Cano Veridiana S.P,
Valentini Sandro R
Publication year - 2003
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(03)01305-x
Subject(s) - biology , microbiology and biotechnology , eukaryotic initiation factor , function (biology) , messenger rna , translation (biology) , eukaryotic translation , biochemistry , gene
The evolutionarily conserved factor eIF5A is the only protein known to undergo hypusination, a unique posttranslational modification triggered by deoxyhypusine synthase (Dys1). Although eIF5A is essential for cell viability, the function of this putative translation initiation factor is still obscure. To identify eIF5A‐binding proteins that could clarify its function, we screened a two‐hybrid library and identified two eIF‐5A partners in S. cerevisiae : Dys1 and the protein encoded by the gene YJR070C , named Lia1 ( igand of e F5 ). The interactions were confirmed by GST pulldown. Mapping binding sites for these proteins revealed that both eIF5A domains can bind to Dys1, whereas the C‐terminal domain is sufficient to bind Lia1. We demonstrate for the first time in vivo that the N‐terminal α‐helix of Dys1 can modulate enzyme activity by inhibiting eIF5A interaction. We suggest that this inhibition be abrogated in the cell when hypusinated and functional eIF5A is required.