Casein kinases are operationally defined by their preferential utilization of acidic proteins such as caseins as substrates. The alpha chain contains the catalytic site. May participate in Wnt signaling. Modulates two aspects of male mating behavior; response to hermaphrodite contact and vulval location, acting in the same pathway as lov-1 and pkd-2. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Tetramer of two alpha and two beta chains. Enriched in cilia in male sensory neurons. Expressed in a subset of the adult male sensory neurons: CEM head neurons, ray RnB neurons, and hook HOB tail neurons. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. CK2 subfamily.