Promotes chemoreceptor gene expression in response to increased cGMP levels by antagonizing the gene repression functions of the class II HDAC hda-4 and the mef-2 transcription factor (PubMed:18832350). Regulates gene expression via recruitment of a histone deacetylase complex containing hda-2, saeg-1 and saeg-2 (PubMed:21573134). Represses body size and lifespan through the dbl-1 and insulin pathways, respectively (PubMed:12571101, PubMed:15330854, PubMed:26434723). May also signal through daf-3 and/or daf-5. Role in egg-laying, dauer formation and motility (PubMed:12571101, PubMed:11181837, PubMed:21573134). Regulates behavioral responses to various chemosensory stimuli in sensory neurons (PubMed:10978280, PubMed:22319638, PubMed:23874221, PubMed:26434723). Required for the initiation of long term adaptation to prolonged odor exposure which results in a decrease in odor seeking behavior (PubMed:12495623, PubMed:20220099, PubMed:26434723). May regulate this process by phosphorylating tax-2, a subunit of cyclic nucleotide-gated channel tax-2/tax-4 (PubMed:12495623). In ASH sensory neurons, negatively regulates avoidance behavior to some bitter tastants, such as quinine, probably by phosphorylating rgs-2 and rgs-3 which are 2 regulator of G-protein signaling proteins (PubMed:23874221). In AWB sensory neurons, involved in avoidance behavior to some repellent odors (PubMed:23954825). In ASE left (ASEL) sensory neuron, involved in the sensing of environmental alkalinity downstream of receptor-type guanylate cyclase gcy-14 (PubMed:23664973). In sensory neurons, involved in the signaling pathway downstream of insulin, TGF-beta and receptor-type guanylate cyclase responsible for inducing quiescence after food intake (PubMed:18316030). Might play a role in aversive olfactory learning in AWC neurons when an odor is associated with food deprivation, depending on the ins-1/age-1 signal from the AIA to the AWC neurons (PubMed:27383131). Probably by regulating neuronal transmission downstream of lin-3 and receptor lin-23 and phospholipase plc-3 in ALA neurons, involved in the decrease in locomotion during the quiescent state that precedes each larval molt (PubMed:17891142). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Binding of cGMP results in enzyme activation. When phosphorylated, interacts with saeg-2. May interact with saeg-1. In resting AWC sensory neurons, localizes in cytoplasm (PubMed:20220099, PubMed:23954825, PubMed:27383131). Prolonged exposure to attractive odorants sensed by AWC neurons results in nuclear translocation (PubMed:20220099, PubMed:23954825, PubMed:27383131). Nuclear translocation is required for the adaptation to prolonged odor exposure and is controlled by G(o)-alpha subunit protein goa-1 (PubMed:23954825, PubMed:20220099, PubMed:27383131). Localization is regulated by cGMP levels: high cGMP levels result in cytoplasmic localization whereas low cGMP levels result in nuclear localization (PubMed:20220099, PubMed:22319638). Nuclear localization in AWC neurons is dependent on age-1 (PubMed:27383131). In addition, an intact sensory cilia structure is required for cytoplasmic localization in resting AWC neurons (PubMed:22319638). In resting AWB sensory neurons, constitutive nuclear localization is dependent on goa-1 (PubMed:23954825). In resting ASH sensory neurons, localizes in both cytoplasm and nucleus (PubMed:23874221). Cytoplasmic localization is important for negative regulation of quinine sensitivity in ASH neurons (PubMed:23874221). Expressed in AWC sensory neurons (at protein level) (PubMed:20220099). Mainly expressed in head neurons, hypodermis, intestine and body wall muscles. L2 and L3 larvae show extensive expression, lower levels are observed in L4 larvae, later embryos and adults. Isoform c is expressed in a subset of neurons in the head, nerve ring, and ventral nerve cord including some motor neurons, also in several neurons in the tail, the pharyngeal marginal cells, body muscle, intestine, vulval muscles, and spermatheca (PubMed:11181837, PubMed:12571101, PubMed:15330854). Autophosphorylated. Increased size and extended lifespan (PubMed:11181837, PubMed:12571101, PubMed:18832350, PubMed:26434723). Defects in chemosensory behavior, egg-laying, synaptic transmission, and dauer formation (PubMed:11181837, PubMed:12571101, PubMed:18832350, PubMed:26434723). Impaired movement of adult animals in response to sensory stimuli (PubMed:10978280). Loss of adaptive behavior to long lasting exposure to attractive odorants (PubMed:20220099). Normal initial chemotaxis response during a first and short exposure to attractive odorants (PubMed:20220099). Loss of chemotaxis response to the repellent odor 2-nonanone (PubMed:23954825). Defective chemotaxis in response to diacetyl and isoamylalcohol (PubMed:26434723). High sensitivity to benzaldehyde, which is retained following pre-exposure in contrast to wild-type animals (PubMed:26434723). Increased basal cGMP levels (PubMed:24015261). Belongs to the protein kinase superfamily. AGC Ser/Thr protein kinase family. cGMP subfamily.