 Sic1 is targeted for degradation by SCF (Cdc4), which recognizes Sic1 phosphodegron pairs.These phosphodegron pairs are closely positioned paired phosphorylation residues that each have strong affinities for Cdc4.In a Sic1 construct with the S69/S76/S80 cluster, processive phosphorylation of these phosphodegron pairs are reliant on Cdk1 sites.