Has guanylyl cyclase on binding to the beta-1 subunit.
Isoform 2 acts as a negative regulator of guanylyl cyclase activity as it forms non-functional heterodimers with the beta subunits.
Subcellular locations: Cytoplasm
Isoform 1 is expressed in fetal brain, liver, colon, endothelium and testis. Isoform 2 is expressed only in liver, colon and endothelium.