Ndd1 Turnover by SCFGrr1 Is Inhibited by the DNA Damage Checkpoint in Saccharomyces cerevisiae

Abstract

In Saccharomyces cerevisiae, Ndd1 is the dedicated transcriptional activator of the mitotic gene cluster, which includes thirty-three genes that encode key mitotic regulators, making Ndd1 a hub for the control of mitosis. Previous work has shown that multiple kinases, including cyclin-dependent kinase (Cdk1), phosphorylate Ndd1 to regulate its activity during the cell cycle. Previously, we showed that Ndd1 was inhibited by phosphorylation in response to DNA damage. Here, we show that Ndd1 is also subject to regulation by protein turnover during the mitotic cell cycle: Ndd1 is unstable during an unperturbed cell cycle, but is strongly stabilized in response to DNA damage. We find that Ndd1 turnover in metaphase requires Cdk1 activity and the ubiquitin ligase SCFGrr1. In response to DNA damage, Ndd1 stabilization requires the checkpoint kinases Mec1/Tel1 and Swe1, the S. cerevisiae homolog of the Wee1 kinase. In both humans and yeast, the checkpoint promotes Wee1-dependent inhibitory phosphorylation of Cdk1 following exposure to DNA damage. While this is critical for checkpoint-induced arrest in most organisms, this is not true in budding yeast, where the function of damage-induced inhibitory phosphorylation is less well understood. We propose that the DNA damage checkpoint stabilizes Ndd1 by inhibiting Cdk1, which we show is required for targeting Ndd1 for destruction.

Three Different Pathways Prevent Chromosome Segregation in the Presence of DNA Damage or Replication Stress in Budding Yeast

“…In addition, the non-phosphorylatable Swe1(AQ) allele is catalytically active ( S8B Fig , right), despite it fails to block M-CDK activity ( Fig 4A ) and chromosome segregation ( S10B Fig ) similarly to the swe1 deletion. Significantly, a recent work dealing with the regulation of SFF transcription in response to DNA damage also places Swe1/Mih1 under the S phase checkpoint [ 39 ].…”

DNA damage kinase signaling: checkpoint and repair at 30 years

“…While DNA damage signaling in budding yeast does not appear to impinge upon the Cdc25 phosphatase homolog Mih1, the budding yeast kinase Swe1 (the WEE1 homolog) is regulated similar to its counterpart in higher eukaryotes and fission yeast. Swe1 is likely phosphorylated and activated by DNA damage signaling, which results in inhibition of M‐CDK (Fig ; Edenberg et al , ; Palou et al , ). DNA damage signaling in budding yeast is also able to suppress M‐CDK activity through additional redundant mechanisms that remain unclear (Palou et al , ).…”

The Cell-Cycle Transcriptional Network Generates and Transmits a Pulse of Transcription Once Each Cell Cycle

“…Indeed, it has been shown that the activity of Hcm1 is regulated by CDK phosphorylation (Landry et al, 2014). On the other hand, Nrm1, Yhp1, and Ndd1 appear to be substrates of APC Cdh1 (Edenberg et al, 2015; Ostapenko and Solomon, 2011; Sajman et al, 2015), which is an E3 ubiquitin ligase complex normally inactivated at G1/S transition by CDK phosphorylation (Huang et al, 2001; Jaspersen et al, 1999; Yeong et al, 2001; Zachariae et al, 1998). If Cdh1 is normally inactivated by CDK at the G1/S border, then the cdc28-4 mutant cells should have constitutively active APC Cdh1 , and thus APC Cdh1 substrates might not accumulate at the protein level.…”