Has a role in substrate recognition in the Skp1-Cullin-1/Cdc53-F-box (SCF) ubiquitin ligase complex. Required for the maintenance of telomere length and transcriptional silencing at the telomere. Also required for chromosome segregation. A part of the E3 ubiquitin ligase Skp1-Cullin-1-F-box (SCF) complex. Interacts with cul1, mcl1 and skp1.