Figure 6.

Pin1 binds to both Ser-179–Pro and Thr-420–Pro sites of SIK2 via its WW domain. A, Pin1 associates with SIK2 through the WW domain. FLAG-tagged SIK2 were overexpressed in 293T cells, and cell lysates were prepared. The cell lysates were incubated with GST protein-conjugated beads, and the proteins were then immunoblotted (IB) with FLAG antibody. B, two Ser/Thr-Pro sites of SIK2 are essential for Pin1 binding. All Ser/Thr-Pro sites in SIK2 were substituted with alanine. Then one of the Ser/Thr residues was restored. Cell lysates including SIK2 mutants were incubated with GST protein-conjugated beads. C, GST–Pin1 was incubated with wild-type SIK2 or the SIK2 mutant in which both Ser-179 and Thr-420 had been switched to alanine. Representative data from one of three independent experiments are shown. CBB, Coomassie Brilliant Blue.