title: The alpha2beta1 isoform of guanylyl cyclase mediates plasma membrane localized nitric oxide signalling.
abstract: Nitric oxide (NO) is a mediator of copious biological processes, in many cases through the production of cGMP from the enzyme nitric oxide-sensitive guanylyl cyclase. Natriuretic peptides also elevate cGMP, often with distinct biological effects, raising the issue of how specificity is achieved. Here we show that a recently described alpha(2)beta(1) isoform of guanylyl cyclase is expressed in a number of epithelia, where it is localized to the apical plasma membrane. We measured the functional properties of the alpha(2)beta(1) isoform by utilizing the NO-dependent activation of the ion channel cystic fibrosis transmembrane conductance regulator (CFTR), which occurs by phosphorylation via the membrane-bound type II isoform of cGMP-dependent protein kinase. We found that cGMP generated by NO activation of the alpha(2)beta(1) isoform of guanylyl cyclase is an exceptionally efficient mediator of nitric oxide action on membrane targets, activating CFTR far more effectively than the cytoplasmically located alpha(1)beta(1) guanylyl cyclase isoform. Targeting the alpha(1)beta(1) isoform of guanylyl cyclase to the membrane also dramatically enhanced the effects of nitric oxide on CFTR within the membrane. This was not due to increased enzymatic activity of guanylyl cyclase in a membrane location, but to production of a localised membrane pool of cGMP by membrane-localized NO-dependent guanylyl cyclase that was resistant to degradation by phosphodiesterases. Selective effects of cGMP produced from this enzyme in response to NO are directed at membrane targets and suggest that drugs selectively activating or inhibiting this alpha(2)beta(1) isoform of guanylyl cyclase may have unique pharmacological properties.
authors.affiliation: Division of Immunology, Infection and Inflammation, University of Glasgow, Glasgow Biomedical Research Centre, 120 University Place, Glasgow, United Kingdom.
authors.forename: Michelle
authors.initials: M
authors.lastname: Bellingham
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Evans
mesh_terms: D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology*; D006152:Cyclic GMP / Q000096:biosynthesis; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism; D004285:Dogs; D006162:Guanylate Cyclase / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000502:physiology; D020033:Protein Isoforms / Q000032:analysis / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000032:analysis / Q000378:metabolism*; D015398:Signal Transduction; D000071756:Soluble Guanylyl Cyclase; D014018:Tissue Distribution
chemical_list: C000605660:GUCY1A2 protein, human; D020030:Nitric Oxide Donors; D020033:Protein Isoforms; D018160:Receptors, Cytoplasmic and Nuclear; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D009569:Nitric Oxide; D010727:Phosphoric Diester Hydrolases; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D006152:Cyclic GMP