Guanylyl cyclase that catalyzes synthesis of cyclic GMP (cGMP) from GTP. GTP = 3',5'-cyclic GMP + diphosphate Homotrimer. Interacts via its C-terminal region with PDZK2. Interacts with the lectin chaperone VIP36. The 145 kDa plasma membrane form of GUCY2C contains sialic acid and galactose residues, while a differencially glycosylated 130 Kda form is a high mannose form that is resident in the endoplasmic reticulum and may serve as the precursor for the cell surface form. The protein kinase domain is predicted to be catalytically inactive. Glycosylation at Asn-62 is required for interaction with VIP36 while glycosylation at Asn-348 and Asn-405 modulates ligand-mediated GC-C activation. Belongs to the adenylyl cyclase class-4/guanylyl cyclase family.