Receptor for the C-type natriuretic peptide NPPC/CNP hormone. Has guanylate cyclase activity upon binding of its ligand. May play a role in the regulation of skeletal growth. GTP = 3',5'-cyclic GMP + diphosphate High levels found in liver, atrium and gill. Moderate levels found in brain and ventricle, and low levels in esophageal sphincter, stomach, posterior intestine and kidney. By osmotic stress; levels decrease under saline conditions. Phosphorylated. Phosphorylation of the protein kinase-like domain is required for full activation by CNP. Glycosylated. Belongs to the adenylyl cyclase class-4/guanylyl cyclase family.