A Ca 2+ -dependent protein kinase not only phosphorylates a substrate but also acts as a scaffold that promotes the interaction between a phosphorylation product and its binding protein. A molecular mechanism to ensure signaling specificity is a scaffold. REPRESSION OF SHOOT GROWTH (RSG) is a tobacco ( Nicotiana tabacum ) transcription factor that is involved in gibberellin feedback regulation. The 14-3-3 proteins negatively regulate RSG by sequestering it in the cytoplasm in response to gibberellins. The N. tabacum Ca 2+ -dependent protein kinase NtCDPK1 was identified as an RSG kinase that promotes 14-3-3 binding of RSG by phosphorylation of RSG. CDPKs are unique sensor responders of Ca 2+ that are only found in plants and some protozoans. Here, we report a scaffolding function of CDPK. 14-3-3 proteins bound to NtCDPK1 by a new mode. Autophosphorylation of NtCDPK1 was necessary for the formation of the binding between NtCDPK1 and 14-3-3 but not for its maintenance. NtCDPK1 formed a heterotrimer with RSG and 14-3-3. Furthermore, we found that NtCDPK1 transfers 14-3-3 to RSG after phosphorylation of RSG and that RSG dissociates from NtCDPK1 as a complex with 14-3-3. These results suggest that NtCDPK1 is an interesting scaffolding kinase that increases the specificity and efficiency of signaling by coupling catalysis with scaffolding on the same protein.