Abstract
A G protein-coupled natriuretic peptide-guanylyl cyclase receptor-B (NPR-B) located in plasma membranes from bovine tracheal smooth muscle shows complex kinetics and regulation. NPR-B was activated by natriuretic peptides (CNP-53 > ANP-28) at the ligand extracellular domain, stimulated by Gq-protein activators, such as mastoparan, and inhibited by Gi-sensitive chloride, interacting at the juxtamembrane domain. The kinase homology domain was evaluated by the ATP inhibition of Mn2+-activated NPR-B, which was partially reversed by mastoparan. The catalytic domain was studied by kinetics of Mn2+/Mg2+ and GTP, and the catalytic effect with GTP analogues with modifications of the /γ phosphates and ribose moieties. Most NPR-B biochemical properties remained after detergent solubilization but the mastoparan activation and chloride inhibition of NPR-B disappeared. Our results indicate that NPR-B is a highly regulated nano-machinery with domains acting at cross-talk points with other signal transducing cascades initiated by G protein-coupled receptors and affected by intracellular ligands such as chloride, Mn2+, Mg2+, ATP, and GTP.
Key Words: :
ABBREVIATIONS: | ||
ANP-28 | = | atrial NP 1-28 |
ARM | = | ATP-regulatory module |
BTSM | = | bovine tracheal smooth muscle |
CD | = | catalytic domain |
CNP-22 | = | C-type NP 1-22 |
CNP-53 | = | C-type NP 1-53 |
GC | = | guanylyl cyclase |
GPCR | = | G protein-coupled receptor |
GPRM | = | G protein regulatory module |
IMBX | = | isomethylbutylxantine |
JMD | = | juxtamembrane domain |
KHD | = | kinase homology domain |
LExD | = | ligand extracellular domain |
Mant-GTP | = | N-methylanthraniloyl 2′ GTP |
NP | = | natriuretic peptide |
NPR-A or GC-A | = | ANP-sensitive guanylyl cyclase |
NPR-B or GC-B | = | CNP-sensitive guanylyl cyclase |
NPR-GC | = | natriuretic peptide receptor guanylyl cyclase |
NPR-C | = | natriuretic peptide receptor clearance |
OG | = | octylglucoside |
OG-GC | = | octylglucoside solubilized guanylyl cyclase |
PMSF | = | phenylmethylsulfonyl fluoride |
PTX | = | pertussis toxin |
sGC | = | soluble guanylyl cyclase |
SNP | = | sodium nitroprusside |
TMD | = | transmembrane domain |
ABBREVIATIONS: | ||
ANP-28 | = | atrial NP 1-28 |
ARM | = | ATP-regulatory module |
BTSM | = | bovine tracheal smooth muscle |
CD | = | catalytic domain |
CNP-22 | = | C-type NP 1-22 |
CNP-53 | = | C-type NP 1-53 |
GC | = | guanylyl cyclase |
GPCR | = | G protein-coupled receptor |
GPRM | = | G protein regulatory module |
IMBX | = | isomethylbutylxantine |
JMD | = | juxtamembrane domain |
KHD | = | kinase homology domain |
LExD | = | ligand extracellular domain |
Mant-GTP | = | N-methylanthraniloyl 2′ GTP |
NP | = | natriuretic peptide |
NPR-A or GC-A | = | ANP-sensitive guanylyl cyclase |
NPR-B or GC-B | = | CNP-sensitive guanylyl cyclase |
NPR-GC | = | natriuretic peptide receptor guanylyl cyclase |
NPR-C | = | natriuretic peptide receptor clearance |
OG | = | octylglucoside |
OG-GC | = | octylglucoside solubilized guanylyl cyclase |
PMSF | = | phenylmethylsulfonyl fluoride |
PTX | = | pertussis toxin |
sGC | = | soluble guanylyl cyclase |
SNP | = | sodium nitroprusside |
TMD | = | transmembrane domain |