Guanylate Cyclase 1 Beta 3 (GUCY1b3)

Soluble guanylate cyclase (sGC), a heterodimeric protein consisting of an alpha subunit and a beta subunit, typically GUCY1B3, catalyzes conversion of GTP to the second messenger cGMP and functions as the main receptor for nitric oxide (NO) and nitrovasodilator drugs.

NOGC had been considered a soluble enzyme, but evidence that the alpha-2 subunit of the alpha-2/beta-1 isoform interacts with the PDZ domain of PSD95 (DLG4) suggests that the alpha-2 subunit directs a membrane association of this isoform. The interaction with PSD95 locates the alpha-2/beta-1 isoform in close proximity to the NO-generating NO synthase (NOS1), thereby enabling the NO sensor to respond to locally raised NO concentrations.