Antagonistic control of DDK binding to licensed replication origins by Mcm2 and Rad53

• DOI: 10.7554/elife.58571
• Publication Date: 2020-07-23T12:03:11Z
• Authors: Syafiq Abd Wahab; Dirk Remus
• Keywords: Replication

Eukaryotic replication origins are licensed by the loading of replicative DNA helicase, Mcm2-7, in inactive double hexameric form around DNA. Subsequent origin activation is under control multiple protein kinases that either promote or inhibit activation, which important for genome maintenance. Using reconstituted budding yeast system, we find flexible N-terminal extension (NTE) Mcm2 promotes stable recruitment Dbf4-dependent kinase (DDK) to Mcm2-7 hexamers, turn DDK phosphorylation Mcm4 and −6 subsequent activation. Conversely, demonstrate checkpoint kinase, Rad53, inhibits binding hexamers. Unexpectedly, this function not dependent on Rad53 activity, suggesting steric inhibition activated Rad53. These findings identify critical determinants reaction uncover a novel mechanism checkpoint-dependent inhibition.