Fig. 1

Hypusine modification and role of eIF5A in translation. a Polyamine pathway leads to spermidine synthesis which is in turn used by deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH) to modify Lys50 of eIF5A in hypusine residue. ODC ornithine decarboxylase, SpdS spermidine synthase, SpmS spermine synthase, AdoMetDC adenosylmethionine decarboxylase, MTA 5′-deoxy-5′-(methylthio)adenosine. b Various roles of eIF5A in protein synthesis. At the initiation step, suppression of ribosomal pausing by eIF5A is necessary to maintain the fidelity of start codon selection. Suppression of ribosomal pausing by eIF5A maintains efficient scanning and translation initiation at the appropriate site (right). In the absence of eIF5A paused ribosomes impede scanning, increases dwell time and initiation at upstream leading to non-optimal start codons (left). eIF5A is crucial in elongation step of protein containing polyproline motifs by preserving from ribosome stalling. Finally, eIF5A participates to translation termination at STOP codon by promoting peptidyl hydrolysis due to release factor activity (RF)