Negative regulator of the cell cycle acting downstream of the cAMP-dependent protein kinase. Part of a glucose-sensing system involved in growth control in response to glucose availability. Phosphorylates POP2. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Shuttles between both compartments in response to glucose. Phosphorylated; highly. Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. MNB/DYRK subfamily.