G-protein-sensitive guanylyl cyclase activity associated with plasma membranes.
A mammalian plasma-membrane-bound guanylyl cyclase is inhibited by NaCl and this inhibition is dependent on GTP concentrations and independent of the chloride salt type. This chloride inhibition is reversed by GTP analogs such as GTP gamma S, suggesting the involvement of G proteins. When the ability of bacterial toxins to affect this chloride-sensitive guanylyl cyclase was examined, pertussis toxin decreased the basal activity and the chloride sensitivity was greatly reduced. Cholera toxin induced a slight activation of the basal activity, without significant changes in the NaCl inhibition. These data indicate that G proteins regulate the chloride sensitivity of this guanylyl cyclase activity. Another property described here is the ability of ATP and analogs to inhibit the basal activity. However, these nucleotides did not modify the chloride sensitivity of the membrane-bound guanylyl cyclase activity.
Lippo de Bécemberg
I
I
Sección de Biomembranas, Universidad Central de Venezuela, Caracas, Venezuela.
Correa de Adjounian
M F
MF
Sánchez de Villaroel
S
S
Peña de Aguilar
E
E
González de Alfonzo
R
R
Alfonzo
M
M
D015720:5'-Nucleotidase / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D015415:Biomarkers; D002417:Cattle; D002458:Cell Fractionation; D002462:Cell Membrane / Q000201:enzymology*; D002712:Chlorides / Q000494:pharmacology; D002772:Cholera Toxin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000187:drug effects / Q000378:metabolism*; D009130:Muscle, Smooth / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D037342:Pertussis Toxin; D013347:Subcellular Fractions / Q000378:metabolism; D014132:Trachea / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D015415:Biomarkers; D002712:Chlorides; D010566:Virulence Factors, Bordetella; C022571:adenosine 5'-O-(3-thiotriphosphate); D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D002772:Cholera Toxin; D037342:Pertussis Toxin; D015720:5'-Nucleotidase; D019204:GTP-Binding Proteins; D006162:Guanylate Cyclase