mRNA-binding protein involved in translation elongation (By similarity). Has an important function at the level of mRNA turnover, probably acting downstream of decapping (By similarity). Critical for the efficient synthesis of peptide bonds between consecutive proline residues (By similarity). 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 (By similarity). With syntenin SDCBP, functions as a regulator of p53/TP53 and p53/TP53-dependent apoptosis (By similarity). Regulates also TNF-alpha-mediated apoptosis (By similarity). Mediates effects of polyamines on neuronal process extension and survival (PubMed:15377278). May play an important role in brain development and function, and in skeletal muscle stem cell differentiation (By similarity). Interacts with DHPS, with SDCBP and DOHH. Found in a complex with Ran and XPO4; the hypusine modification increases the interaction with XPO4. Hypusine modification promotes the nuclear export and cytoplasmic localization and there was a dynamic shift in the localization from predominantly cytoplasmic to primarily nuclear under apoptotic inducing conditions. Nuclear export of hypusinated protein is mediated by XPO4. Acetylated by PCAF/KAT2B, regulating its subcellular localization (By similarity). Deacetylated by SIRT2 (By similarity). Lys-50 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. Belongs to the eIF-5A family.