Fig. 8. CDK1 phosphorylation serves as a molecular switch that regulates the association of RII with centrosomal AKAP450. We propose this model for the regulation of RII association with AKAP450 by CDK1 phosphorylation. In interphase cells, unphosphorylated RII is tightly bound to the centrosomes through interaction with AKAP450. At mitosis entry, RII is phosphorylated at T54 by CDK1 and the centrosomal anchoring is disrupted. The binding is restored at mitosis exit by dephosphorylation of RII by a threonine phosphatase.