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

Research 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 SpCENPA NTD interacting protein that is dependent on GRANT proline residues. Ectopic expression of sim3+ complemented the chromosome segregation defect arising fromthe loss of these proline residues. Overall, cis–trans proline isomerization is a posttranslational modification of the SpCENP-A NTD that confers precise propagation of centromeric integrity in fission yeast, presumably via targeting SpCENP-A to the centromere.
Research Authors
Hwei Ling Tan, Kim Kiat Lim, Qiaoyun Yang, Jing-Song Fan,
Ahmed Mahmoud Mohammed Sayed, Liy Sim Low, Bingbing Ren, Teck Kwang Lim,
Qingsong Lin, Yu-Keung Mok, Yih-Cherng Liou and Ee Sin Chen
Research Department
Research Journal
Nucleic acids research
Research Pages
NULL
Research Publisher
Oxford University Press
Research Rank
1
Research Vol
NULL
Research Website
NULL
Research Year
2018