 A simple Sic1 construct containing 5 phosphorylation residues (1 priming site and two phosphodegron pairs) revealed that any slight movement of the priming site can have significant effects on cell cycle progression.The priming site should be within the +12 to +16 range of both residues in the phosphodegron pair to maximize phosphorylation.Sic1 phosphorylation is initiated by the G1 cyclins, Cln1,2, and then completed by S-phase cyclins, Clb5,6 (Fig.