Prolyl isomerization of the CENP-A N-terminus regulates centromeric integrity in fission yeast

Nucleic Acids Res. 2018 Feb 16;46(3):1167-1179. doi: 10.1093/nar/gkx1180.

Abstract

Centromeric identity and chromosome segregation are determined by the precise centromeric targeting of CENP-A, the centromere-specific histone H3 variant. The significance of the amino-terminal domain (NTD) of CENP-A in this process remains unclear. Here, we assessed the functional significance of each residue within the NTD of CENP-A from Schizosaccharomyces pombe (SpCENP-A) and identified a proline-rich 'GRANT' (Genomic stability-Regulating site within CENP-A N-Terminus) motif that is important for CENP-A function. Through sequential mutagenesis, we show that GRANT proline residues are essential for coordinating SpCENP-A centromeric targeting. GRANT proline-15 (P15), in particular, undergoes cis-trans isomerization to regulate chromosome segregation fidelity, which appears to be carried out by two FK506-binding protein (FKBP) family prolyl cis-trans isomerases. Using proteomics analysis, we further identified the SpCENP-A-localizing chaperone Sim3 as a SpCENP-A NTD interacting protein that is dependent on GRANT proline residues. Ectopic expression of sim3+ complemented the chromosome segregation defect arising from the loss of these proline residues. Overall, cis-trans proline isomerization is a post-translational modification of the SpCENP-A NTD that confers precise propagation of centromeric integrity in fission yeast, presumably via targeting SpCENP-A to the centromere.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Centromere / metabolism*
  • Centromere / ultrastructure
  • Chromosomal Proteins, Non-Histone / genetics
  • Chromosomal Proteins, Non-Histone / metabolism*
  • Chromosome Segregation
  • Chromosomes, Fungal / chemistry
  • Chromosomes, Fungal / metabolism*
  • Genetic Complementation Test
  • Genomic Instability
  • Isomerism
  • Kinetics
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Proline / chemistry
  • Proline / metabolism*
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Protein Processing, Post-Translational*
  • Schizosaccharomyces / genetics
  • Schizosaccharomyces / metabolism*
  • Schizosaccharomyces pombe Proteins / genetics
  • Schizosaccharomyces pombe Proteins / metabolism*
  • Sequence Alignment
  • Tacrolimus Binding Proteins / genetics
  • Tacrolimus Binding Proteins / metabolism

Substances

  • Chromosomal Proteins, Non-Histone
  • Cnp1 protein, S pombe
  • Nuclear Proteins
  • Protein Isoforms
  • Schizosaccharomyces pombe Proteins
  • Sim3 protein, S pombe
  • Proline
  • Tacrolimus Binding Proteins