GUCY1A1

GUCY1A1 encodes the α1 subunit of soluble guanylate cyclase (sGC), which heterodimerizes with the β1 subunit and catalyzes cGMP production upon nitric oxide (NO) stimulation to mediate vascular smooth muscle relaxation, platelet inhibition, angiogenesis, and endothelial cell survival (PMID:27342234, PMID:28487391, PMID:40856046). The transcription factor ZEB1 drives GUCY1A1 expression by binding an intronic regulatory element, and higher α1 levels enhance cGMP-mediated inhibition of platelet aggregation and vascular smooth muscle cell migration (PMID:28487391). Downstream of sGC-generated cGMP, PKG phosphorylates LDHA at T95, activating a moonlighting kinase function that phosphorylates GPX4 at S131 to prevent its chaperone-mediated autophagic degradation, thereby suppressing endothelial ferroptosis and protecting against microvascular no-reflow injury (PMID:40856046). Loss-of-function variants in GUCY1A1 cause blunted NO–cGMP signaling and are linked to moyamoya angiopathy, coronary artery disease, and hypertension (PMID:26777256, PMID:27342234, PMID:36941667).

1. 2004 Medium

   Establishing that GUCY1A1-driven cGMP production lies upstream of VEGF expression and angiogenesis resolved how sGC activity couples to tumor vascularization.

   Evidence Antisense knockdown in glioma cells with cGMP measurement, VEGF assays, HUVEC co-culture, and nude mouse tumor vascularization

   PMID:15201957

   Open questions at the time

   • Mechanism linking cGMP to VEGF transcription not delineated
   • Antisense approach lacks genetic specificity of modern KO methods
   • Not replicated in non-tumor vascular beds
2. 2014 Medium

   Demonstration that the α1-A680T variant produces a gain-of-function sGC with enhanced NO sensitivity established that GUCY1A1 activity is tunable in both directions and that increased function protects against pulmonary hypertension.

   Evidence Purified mutant protein enzymatic assay and reporter cell cGMP assay

   PMID:25373139

   Open questions at the time

   • Single variant studied
   • No in vivo confirmation of hemodynamic protection by this allele alone
   • Structural basis for enhanced NO sensitivity not resolved
3. 2016 High

   Functional characterization of multiple rare coding variants from MI patients demonstrated that loss-of-function mutations reduce NO-stimulated cGMP production while preserving β1 heterodimerization, and that pharmacological sGC stimulation can rescue activity, defining a therapeutic rationale.

   Evidence Co-immunoprecipitation for dimerization, cGMP radioimmunoassay in HEK293 cells, pharmacological rescue with BAY 41-2272

   PMID:27342234

   Open questions at the time

   • Rescue not tested in vivo or in patient-derived cells
   • Platelet and vascular phenotypes not directly measured for each variant
4. 2016 Medium

   Characterization of the C517Y missense variant as catalytically impaired directly linked a specific GUCY1A1 mutation to moyamoya disease and hypertension through blunted NO-cGMP signaling.

   Evidence Biochemical functional assay of mutant protein response to NO donor in vitro

   PMID:26777256

   Open questions at the time

   • Single variant in single family
   • No vascular cell or animal model confirmation
   • Protein stability and expression levels not fully characterized
5. 2017 High

   Identifying ZEB1 as a transcriptional regulator of GUCY1A1 via allele-specific binding at rs7692387 connected a common CAD-risk SNP to a molecular mechanism controlling sGC expression and downstream platelet and vascular smooth muscle function.

   Evidence Allele-specific ChIP, siRNA/overexpression of ZEB1, reporter assays, ex vivo platelet aggregation, VSMC migration assay

   PMID:28487391

   Open questions at the time

   • Other transcription factors at this locus not excluded
   • In vivo confirmation of ZEB1 regulation of GUCY1A1 in arterial tissue lacking
6. 2023 High

   Endothelial-specific Gucy1a1 knockout in mice revealed a PKG→LDHA(T95-P)→GPX4(S131-P) signaling cascade that suppresses ferroptosis by blocking chaperone-mediated autophagic degradation of GPX4, explaining how sGC-cGMP protects against microvascular no-reflow injury.

   Evidence EC-specific conditional KO and AAV overexpression in mice; mass spectrometry; CRISPR mutagenesis of phosphosites; Co-IP; CMA assay

   PMID:40856046

   Open questions at the time

   • LDHA's moonlighting kinase activity awaits structural characterization
   • Relevance of this pathway in non-cardiac vascular beds not tested
   • Whether other PKG substrates contribute to anti-ferroptotic protection is unknown
7. 2023 Medium

   Gucy1a3 knockout mice showed worsened stroke outcomes with reduced HIF-1α and VEGFA, positioning sGC upstream of the HIF-1α/VEGFA angiogenic axis in cerebral ischemia.

   Evidence KO mouse permanent MCAO model; TTC staining; CD31 immunohistochemistry; western blot for HIF-1α/VEGFA

   PMID:38064974

   Open questions at the time

   • Direct cGMP-dependent mechanism linking sGC to HIF-1α stabilization unresolved
   • Single lab, single ischemia model
   • Endothelial versus neuronal contributions not dissected
8. 2023 Medium

   A biallelic catalytic-domain missense variant confirmed by absent protein expression in patient cells solidified the genetic basis for moyamoya angiopathy as a loss-of-function GUCY1A1 disease.

   Evidence Exome sequencing, western blot of patient endothelial progenitor cells, 3D structural modeling

   PMID:36941667

   Open questions at the time

   • No enzymatic activity assay of the mutant protein performed
   • Rescue experiment not attempted
   • Small number of patients studied

• It remains unknown how sGC-derived cGMP mechanistically stabilizes HIF-1α, whether the LDHA moonlighting kinase pathway operates in non-cardiac vascular beds, and what structural features govern the differential activity of disease-associated α1 variants.
• No structural model of full-length α1β1 heterodimer with disease mutations mapped
• cGMP-to-HIF-1α link not biochemically resolved
• Tissue-specific requirements for sGC anti-ferroptotic signaling unknown