1. An acidic loop in the forkhead-associated domain of the yeast meiosis-specific kinase Mek1 interacts with a specific motif in a subset of Mek1 substrates.
- Author
-
Weng Q, Wan L, Straker GC, Deegan TD, Duncker BP, Neiman AM, Luk E, and Hollingsworth NM
- Subjects
- Phosphorylation, Protein Binding, DNA Breaks, Double-Stranded, Nuclear Proteins metabolism, Nuclear Proteins genetics, Nuclear Proteins chemistry, Amino Acid Motifs, DNA-Binding Proteins metabolism, DNA-Binding Proteins genetics, DNA-Binding Proteins chemistry, Transcription Factors, Saccharomyces cerevisiae Proteins metabolism, Saccharomyces cerevisiae Proteins genetics, Saccharomyces cerevisiae Proteins chemistry, Saccharomyces cerevisiae genetics, Saccharomyces cerevisiae metabolism, MAP Kinase Kinase 1 metabolism, MAP Kinase Kinase 1 genetics, Meiosis
- Abstract
The meiosis-specific kinase Mek1 regulates key steps in meiotic recombination in the budding yeast, Saccharomyces cerevisiae. MEK1 limits resection at double-strand break (DSB) ends and is required for preferential strand invasion into homologs, a process known as interhomolog bias. After strand invasion, MEK1 promotes phosphorylation of the synaptonemal complex protein Zip1 that is necessary for DSB repair mediated by a crossover-specific pathway that enables chromosome synapsis. In addition, Mek1 phosphorylation of the meiosis-specific transcription factor, Ndt80, regulates the meiotic recombination checkpoint that prevents exit from pachytene when DSBs are present. Mek1 interacts with Ndt80 through a 5-amino acid sequence, RPSKR, located between the DNA-binding and activation domains of Ndt80. AlphaFold Multimer modeling of a fragment of Ndt80 containing the RPSKR motif and full-length Mek1 indicated that RPSKR binds to an acidic loop located in the Mek1 FHA domain, a noncanonical interaction with this motif. A second protein, the 5'-3' helicase Rrm3, similarly interacts with Mek1 through an RPAKR motif and is an in vitro substrate of Mek1. Genetic analysis using various mutants in the MEK1 acidic loop validated the AlphaFold model, in that they specifically disrupt 2-hybrid interactions with Ndt80 and Rrm3. Phenotypic analyses further showed that the acidic loop mutants are defective in the meiotic recombination checkpoint and, in certain circumstances, exhibit more severe phenotypes compared to the NDT80 mutant with the RPSKR sequence deleted, suggesting that additional, as yet unknown, substrates of Mek1 also bind to Mek1 using an RPXKR motif., Competing Interests: Conflicts of interest: The authors declare no conflicts of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Genetics Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)
- Published
- 2024
- Full Text
- View/download PDF