CKLiK^297-321 inhibits CKLiK kinase activity. A cell permeable CKLiK peptide YGRKKRRQRRRIRKNFAKSKWRQAFNATAVVRHMRK was synthesized. (A) 32D cells stably expressing HA-CKLiK were lysed, and CKLiK was immunoprecipitated. CKLiK kinase assays were performed with increasing concentrations of CKLiK^297-321 as indicated. CREMβ was used as a substrate. A scrambled tat-control peptide was used a negative control. (B) COS cells were transiently transfected with 100 ng HA-CKLiK-296 or HA-CKLiK-WT (wild type). CKLiK was immune-precipitated with an antibody against the HA-epitope tag, and kinase assays were performed in the absence of Ca²⁺/calmodulin. Kinase assays with HA-CKLiK-WT were performed in the presence or absence of Ca²⁺/calmodulin, as positive and negative control, respectively.