Guanylate cyclase involved in the production of the second messenger cGMP (By similarity). Regulates chemotaxis responses toward the salt ion Mg(2+) and to a lesser extent toward Cl(1-) in ASE left (ASEL) sensory neuron (PubMed:19523832). GTP = 3',5'-cyclic GMP + diphosphate Expressed in both ASEL and ASER neurons throughout late embryonic and early larval stages. In adults, expressed asymmetrically in ASE left (ASEL) sensory neuron. The protein kinase domain is predicted to be catalytically inactive. Belongs to the adenylyl cyclase class-4/guanylyl cyclase family.