Serine/threonine-protein kinase, which, in association with cyy-1, regulates the trafficking of synaptic vesicles in the DA9 motor neuron and probably also in the DD motor neurons and in RIA interneurons. Sufficient for synaptic vesicle trafficking in the DA9 motor neuron. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Binds 2 Mg(2+) ions. Interacts with cyy-1; the interaction is required to activate pct-1. Evenly distributed in the dendrite, the axon and the cell body of the DA motor neuron. Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. CDC2/CDKX subfamily.