SUMOylation regulates telomere length homeostasis by targeting Cdc13

Cdc13 forms a complex with Stn1-Ten1 that caps budding yeast telomeres; Cdc13 also recruits the telomerase complex. Indeed, Cdk1 phosphorylates Cdc13 and this favors the Cdc13- Est1p, at the expense of Cdc13 association with Stn1, which inhibits telomerase action at telomeres. Now a second, independent mechanism to control Cdc13-Stn1 interaction is revealed: sumoylation of Cdc13 promotes its interaction with Stn1 and prevents telomerase activity.