Is there a role for eIF5A in translation?
The putative translation factor eIF5A is essential for cell viability and is highly conserved from archaebacteria to mammals. This factor is the only cellular protein that undergoes an essential posttranslational modification dependent on the polyamine spermidine, called hypusination. This review focuses on the functional characterization of eIF5A. Although this protein was originally identified as a translation initiation factor, subsequent studies did not support a role for eIF5A in general translation initiation. eIF5A has also been implicated in nuclear export of HIV-1 Rev and mRNA decay, but these findings are controversial in the literature and may reflect secondary effects of eIF-5A function. Next, the involvement of eIF5A and hypusination in the control of the cell cycle and proliferation in various organisms is reviewed. Finally, recent evidence in favor of reconsidering the role of eIF5A as a translation factor is discussed. Future studies may reveal the specific mechanism by which eIF5A affects protein synthesis.
Zanelli
C F
CF
Department of Biological Sciences, School of Pharmaceutical Sciences, São Paulo State University - UNESP, Araraquara, Brazil.
Valentini
S R
SR
D000595:Amino Acid Sequence; D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D006801:Humans; D008969:Molecular Sequence Data; D010448:Peptide Initiation Factors / Q000235:genetics / Q000502:physiology*; D014176:Protein Biosynthesis / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D016415:Sequence Alignment; D054321:rev Gene Products, Human Immunodeficiency Virus / Q000096:biosynthesis; D000097574:Eukaryotic Translation Initiation Factor 5A
D010448:Peptide Initiation Factors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D054321:rev Gene Products, Human Immunodeficiency Virus; D000097574:Eukaryotic Translation Initiation Factor 5A; C514860:rev protein, Human Immunodeficiency Virus-1