The telomere-binding protein Rif2 and ATP-bound Rad50 have opposing roles in the activation of yeast Tel1(ATM) kinase Journal Article
| Authors: | Hailemariam, S.; De Bona, P.; Galletto, R.; Hohl, M.; Petrini, J. H.; Burgers, P. M. |
| Article Title: | The telomere-binding protein Rif2 and ATP-bound Rad50 have opposing roles in the activation of yeast Tel1(ATM) kinase |
| Abstract: | Saccharomyces cerevisiae Tel1 is the ortholog of human ATM kinase and initiates a cell cycle checkpoint in response to dsDNA breaks (DSBs). Tel1ATM kinase is activated synergistically by naked dsDNA and the Mre11-Rad50-Xrs2NBS1 complex (MRX). A multisubunit protein complex, which is related to human shelterin, protects telomeres from being recognized as DSBs, thereby preventing a Tel1ATM checkpoint response. However, at very short telomeres, Tel1ATM can be recruited and activated by the MRX complex, resulting in telomere elongation. Conversely, at long telomeres, Rap1-interacting-factor 2 (Rif2) is instrumental in suppressing Tel1 activity. Here, using an in vitro reconstituted Tel1 kinase activation assay, we show that Rif2 inhibits MRX-dependent Tel1 kinase activity. Rif2 discharges the ATP-bound form of Rad50, which is essential for all MRX-dependent activities. This conclusion is further strengthened by experiments with a Rad50 allosteric ATPase mutant that maps outside the conserved ATP binding pocket. We propose a model in which Rif2 attenuates Tel1 activity at telomeres by acting directly on Rad50 and discharging its activated ATP-bound state, thereby rendering the MRX complex incompetent for Tel1 activation. These findings expand our understanding of the mechanism by which Rif2 controls telomere length. © 2019 Hailemariam et al. Published under exclusive license by The American Society for Biochemistry and Molecular Biology, Inc. |
| Keywords: | yeast; kinase activity; enzymes; chromosomes; kinase activation; chemical activation; binding proteins; telomere length; multisubunit; protein complexes; atp binding pockets; bound state |
| Journal Title: | Journal of Biological Chemistry |
| Volume: | 294 |
| Issue: | 49 |
| ISSN: | 0021-9258 |
| Publisher: | American Society for Biochemistry and Molecular Biology |
| Date Published: | 2019-12-06 |
| Start Page: | 18846 |
| End Page: | 18852 |
| Language: | English |
| DOI: | 10.1074/jbc.RA119.011077 |
| PUBMED: | 31640985 |
| PROVIDER: | scopus |
| PMCID: | PMC6901328 |
| DOI/URL: | |
| Notes: | Article -- Export Date: 2 January 2020 -- Source: Scopus |
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