Yra2 regulates proteolysis of Cse4 to prevent its mislocalization to non-centromeric regions for chromosomal stability in budding yeast

Authors

Mishra, P. K., Ohkuni, K., Raymond, P., Costanzo, M., Boone, C., Zenklusen, D., Basrai, M. A.

Abstract

Restricting the localization of centromere-specific histone H3 variant Cse4 (CENP-A in humans) to centromeric chromatin is essential for chromosome segregation. Mislocalization of overexpressed Cse4/CENP-A to non-centromeric regions contributes to chromosomal instability (CIN) in model organisms and human cells. CIN is an important hallmark of many cancers and hence defining mechanisms that prevent mislocalization of Cse4 is clinically significant. Here we report a role for YRA2 (Yeast RNA Annealing Protein 2) in ubiquitin mediated proteolysis of Cse4 to prevent its mislocalization for chromosomal stability. YRA2 was identified in a genome-wide screen for gene deletions that exhibit synthetic dosage lethality (SDL) upon overexpression of CSE4 (GALCSE4). We determined that yra2{triangleup} strains exhibit increased Cse4 stability, enriched Cse4 chromatin association, reduced Cse4 ubiquitination, Cse4 mislocalization, and CIN. Defects in interaction of E3 ubiquitin ligase Psh1 with Cse4 contributes to stability of Cse4 in yra2{triangleup} strains. Consistent with these results, overexpression of PSH1 suppresses GALCSE4 SDL in yra2{triangleup} strain. We determined that Yra2 mediated proteolysis of Cse4 is independent of its RNA related functions as strain deleted for the C-terminal ChTOP domain of Yra2 with an intact N-terminal RNA binding domain exhibits GALCSE4 SDL and defects in Cse4 proteolysis. Furthermore, poly(A)+ RNA export mutants in YRA1 (yra1-2) and MEX67 (mex67-5), that interact with Yra2, do not exhibit GALCSE4 SDL and defects in RNA export are not observed in yra2{Delta} cells. In summary, we have defined a key role for Yra2 in preventing mislocalization of Cse4 by facilitating its proteolysis to preserve chromosomal stability.

Preprint server: bioRxiv
The authors list and abstract were imported from bioRxiv on 13 Aug 2026.

Stats

1-terrible, 9-excellent. How would you rate this preprint? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.