Guanylate cyclase involved in the production of the second messenger cGMP (By similarity). Regulates chemotaxis responses toward Li(1-), Mg(2+), Cl(1-), Br(1)- and I(1-) salt ions and methionine in ASE right (ASER) sensory neuron (PubMed:19523832, PubMed:20837997). May regulate ASER neuronal activity such as axon sprouting and calcium responses to changes in salt concentrations (PubMed:19523832). GTP = 3',5'-cyclic GMP + diphosphate Expression in ASER neuron begins at an early larval stage and is maintained in the adult. The extracellular and guanylate cyclase domains are essential for chemosensory responses. The protein kinase domain is predicted to be catalytically inactive. Belongs to the adenylyl cyclase class-4/guanylyl cyclase family.