Protein disulfide-isomerase interacts with soluble guanylyl cyclase via a redox-based mechanism and modulates its activity

Erin J. Heckler, Pierre Antoine Crassous, Padmamalini Baskaran, Annie Beuve

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16 Scopus citations


NO binds to the receptor sGC (soluble guanylyl cyclase), stimulating cGMP production. The NO-sGC-cGMP pathway is a key component in the cardiovascular system. Discrepancies in sGC activation and deactivation in vitro compared with in vivo have led to a search for endogenous factors that regulate sGC or assist in cellular localization. In our previous work, which identified Hsp (heat-shock protein) 70 as a modulator of sGC, we determined that PDI (protein disulfide-isomerase) bound to an sGC-Affinity matrix. In the present study, we establish and characterize this interaction. Incubation of purified PDIwith semipurified sGC, both reduced and oxidized, resulted in different migration patterns on non-reducing Western blots indicating a redox component to the interaction. In sGC-infected COS-7 cells, transfected FLAG-tagged PDI and PDI CXXS (redox active site 'trap mutant') pulled down sGC. This PDI-sGC complex was resolved by reductant, confirming a redox interaction. PDI inhibited NO-stimulated sGC activity in COS-7 lysates, however, a PDI redox-inactive mutant PDI SXXS did not. Together, these data unveil a novel mechanism of sGC redox modulation via thiol-disulfide exchange. Finally, in SMCs (smooth muscle cells), endogenous PDI and sGC co-localize by in situ proximity ligation assay, which suggests biological relevance. PDI-dependent redox regulation of sGCNOsensitivity may provide a secondary control over vascular homoeostasis.

Original languageEnglish (US)
Pages (from-to)161-169
Number of pages9
JournalBiochemical Journal
Issue number1
StatePublished - May 15 2013

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology


  • Nitric oxide (NO)
  • Protein disulfide-isomerase (PDI)
  • Redox regulation
  • Smooth muscle cell (SMC)
  • Soluble guanylyl cyclase (sGC)


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