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

• Published in: Nucleic acids research 2018-02, Vol.46 (3), p.1167-1179
• Main Authors: Tan, Hwei Ling, Lim, Kim Kiat, Yang, Qiaoyun, Fan, Jing-Song, Sayed, Ahmed Mahmoud Mohammed, Low, Liy Sim, Ren, Bingbing, Lim, Teck Kwang, Lin, Qingsong, Mok, Yu-Keung, Liou, Yih-Cherng, Chen, Ee Sin
• Format: Article
• Language: English
• Subjects: 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; Gene regulation, Chromatin and Epigenetics; 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
• ISSN: 0305-1048; 1362-4962
• 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.