Regulation of nitric oxide-responsive recombinant soluble guanylyl cyclase by calcium.

摘要: Calcium (Ca2+) and cyclic GMP (cGMP) subserve antagonistic functions that are reflected in their coordinated reciprocal regulation physiological systems. However, molecular mechanisms by which Ca2+ regulates cGMP-dependent signaling remain incompletely defined. In this study, the inhibition of recombinant nitric oxide (NO)-stimulated soluble guanylyl cyclase (SGC) was demonstrated. The alpha- beta-subunits rat SGC were heterologously coexpressed HEK 293 cells do not express NO synthase, whose Ca2+-stimulated activity can confound effects cation on SGC. inhibited basal NO-stimulated a concentration- guanine nucleotide-dependent fashion. This crude cell extracts immunopurified preparations. lowered both Vmax Km via an uncompetitive mechanism through direct interaction with enzyme. intact cells, increases intracellular concentration induced ionomycin, ionophore, thapsigargin, releases stores cation, cGMP accumulation. Similarly, carbachol-induced elevation accumulation cells. These data demonstrate behaves as sensitive detector may play central role coordinating Ca2+- mechanisms.