Soluble guanylate cyclase alpha subunit (sGCα)

Soluble guanylate cyclase alpha subunit is part of the heterodimeric soluble guanylate cyclase (sGC), a critical intracellular receptor and enzyme for nitric oxide (NO) signaling in mammals[1][2][4][5][6]. The functional sGC enzyme consists of an alpha (α, isoforms sGCα1 or sGCα2) and a beta (β1) subunit heterodimer, and is the principal receptor for NO, which binds to the heme-containing domain of the β subunit[2][3][5]. Upon activation by NO, sGC converts GTP to cyclic GMP (cGMP), a second messenger mediating smooth muscle relaxation, vasodilation, inhibition of platelet aggregation, and neuronal signaling[2][4]. sGC (and its alpha subunit) is a validated therapeutic target for cardiovascular diseases, and its function is exploited by both endogenous NO and pharmacologic sGC stimulators (such as riociguat and vericiguat) as well as by drugs that generate NO (organic nitrates)[3][4][5][6]. The sGCα1–β1 dimer is ubiquitously expressed, while α2–β1 has tissue-specific enrichment (e.g., brain, kidney, placenta)[2]. Dysfunction or altered expression of sGC alpha subunits is implicated in several cardiovascular and neurologic pathologies[2][4][5][9].

Other names

sGC alpha subunitGuanylyl cyclase soluble subunit alphaAlpha subunit of soluble guanylate cyclaseGUCY1A1 (gene for alpha-1)GUCY1A2 (gene for alpha-2)Soluble guanylyl cyclase alpha subunit

Stimulation or activation of sGC to increase cGMP production (as with NO or sGC stimulators like riociguat/vericiguat). Allosteric activation by direct binding of NO to the heme-binding site on the β subunit. Allosteric stimulation by sGC stimulators binding at subunit interfaces, stabilizing the active conformation.