Phosphorylation of Elp1 by Hrr25 is required for elongator-dependent tRNA modification in yeast

PLoS Genet. 2015 Jan 8;11(1):e1004931. doi: 10.1371/journal.pgen.1004931. eCollection 2015 Jan.


Elongator is a conserved protein complex comprising six different polypeptides that has been ascribed a wide range of functions, but which is now known to be required for modification of uridine residues in the wobble position of a subset of tRNAs in yeast, plants, worms and mammals. In previous work, we showed that Elongator's largest subunit (Elp1; also known as Iki3) was phosphorylated and implicated the yeast casein kinase I Hrr25 in Elongator function. Here we report identification of nine in vivo phosphorylation sites within Elp1 and show that four of these, clustered close to the Elp1 C-terminus and adjacent to a region that binds tRNA, are important for Elongator's tRNA modification function. Hrr25 protein kinase directly modifies Elp1 on two sites (Ser-1198 and Ser-1202) and through analyzing non-phosphorylatable (alanine) and acidic, phosphomimic substitutions at Ser-1198, Ser-1202 and Ser-1209, we provide evidence that phosphorylation plays a positive role in the tRNA modification function of Elongator and may regulate the interaction of Elongator both with its accessory protein Kti12 and with Hrr25 kinase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Alanine / genetics
  • Casein Kinase I / genetics*
  • Casein Kinase I / metabolism
  • Gene Expression Regulation, Fungal
  • Histone Acetyltransferases / genetics*
  • Histone Acetyltransferases / metabolism
  • Multiprotein Complexes / genetics
  • Peptide Elongation Factors / genetics*
  • Peptide Elongation Factors / metabolism
  • Phenotype
  • Phosphorylation
  • RNA, Transfer / genetics*
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae Proteins / genetics*
  • Saccharomyces cerevisiae Proteins / metabolism
  • Uridine / genetics


  • Adaptor Proteins, Signal Transducing
  • KTI12 protein, S cerevisiae
  • Multiprotein Complexes
  • Peptide Elongation Factors
  • Saccharomyces cerevisiae Proteins
  • RNA, Transfer
  • Histone Acetyltransferases
  • IKI3 protein, S cerevisiae
  • Casein Kinase I
  • HRR25 protein, S cerevisiae
  • Alanine
  • Uridine