Essential for larval development (PubMed:22887816). Controls the rhythmic contraction of enteric muscles probably by regulating G-protein coupled receptor aex-2-mediated calcium influx in GABAergic DVB neurons (PubMed:24086161). Plays a role in the control of oocyte meiotic maturation by gonadal sheath cells (PubMed:22887816). Isoforms a and b: May play a role in the regulation of neuromuscular junctions. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Binding of cAMP to kin-2 regulatory subunits induces dissociation of the heterotetramer. The released catalytic subunits are active and able to phosphorylate their substrates. Heterotetramer composed of two regulatory subunits and two catalytic subunits. Experimental confirmation may be lacking for some isoforms. Expressed at low levels in the embryo. Expression increases after hatching and during larval stages and, despite a decrease, remains high in adults (at protein level). Isoform h and isoform j are myristoylated. RNAi-mediated knockdown of isoforms a and b in neurons shows a temperature-sensitive adult onset paralysis of the distal part of the body resulting in the loss of backward movements and an inability to lay eggs. RNAi-mediated knockdown of isoforms f and k results in no obvious phenotype. Belongs to the protein kinase superfamily. AGC Ser/Thr protein kinase family. cAMP subfamily.