Indications for a moonlighting function of translation factor aIF5A in the crenarchaeum Sulfolobus solfataricus

RNA Biol. 2019 May;16(5):675-685. doi: 10.1080/15476286.2019.1582953. Epub 2019 Mar 5.


Translation factor a/eIF5A is highly conserved in Eukarya and Archaea. The eukaryal eIF5A protein is required for transit of ribosomes across consecutive proline codons, whereas the function of the archaeal orthologue remains unknown. Here, we provide a first hint for an involvement of Sulfolobus solfataricus (Sso) aIF5A in translation. CRISPR-mediated knock down of the aif5A gene resulted in strong growth retardation, underlining a pivotal function. Moreover, in vitro studies revealed that Sso aIF5A is endowed with endoribonucleolytic activity. Thus, aIF5A appears to be a moonlighting protein that might be involved in protein synthesis as well as in RNA metabolism.

Keywords: Archaea; RNase; Translation factor aIF5A.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Archaeal Proteins / genetics
  • Archaeal Proteins / metabolism
  • CRISPR-Cas Systems
  • Peptide Initiation Factors / genetics
  • Peptide Initiation Factors / metabolism*
  • Protein Biosynthesis*
  • RNA, Archaeal / metabolism
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Sulfolobus solfataricus / growth & development*
  • Sulfolobus solfataricus / metabolism


  • Archaeal Proteins
  • Peptide Initiation Factors
  • RNA, Archaeal
  • RNA-Binding Proteins
  • eukaryotic translation initiation factor 5A

Grant support

Funds provided by Austrian Science Fund (FWF). This work was supported by Grant 22888 from the Austrian Science Fund to UB and by funds (RSA2017) from the Polytechnic University of Marche to ALT.