mRNA-binding protein involved in translation elongation. Has an important function at the level of mRNA turnover, probably acting downstream of decapping. Critical for the efficient synthesis of peptide bonds between consecutive proline residues. Can resolve ribosomal stalling caused by consecutive prolines during translation (By similarity). Involved in actin dynamics and cell cycle progression, mRNA decay and probably in a pathway involved in stress response and maintenance of cell wall integrity. Essential for polarized growth, a process necessary for G1/S transition. May mediate large range of effects of the polyamine spermidine in the cell. Homodimer. Interacts with DYS1 and LIA1. Concentrates in the perinuclear region. Expressed in aerobic conditions. Lys-51 undergoes hypusination, a unique post-translational modification that consists in the addition of a butylamino group from spermidine to lysine side chain, leading to the formation of the unusual amino acid hypusine. eIF-5As are the only known proteins to undergo this modification, which is essential for their function. There are two genes for eIF-5A in yeast. Belongs to the eIF-5A family. Was originally thought (PubMed:641056) to be a translation initiation factor but further analysis (PubMed:19424157 and PubMed:19338753) clearly suggests that it is involved in translation elongation and not translation initiation. subclass.