A high-affinity bradykinin receptor in membranes from rat myometrium is coupled to pertussis toxin-sensitive G-proteins of the Gi family.
In rat myometrial membranes, two 3H-Bradykinin binding sites with KD values of 16 pM and 1.0 nM were identified. Employed at pM concentrations, bradykinin stimulated high affinity GTPases. This effect was abolished by the bradykinin antagonist, [D-Arg(Hyp3-Thi5,8, D-Phe7)]bradykinin (10 microM), and by treatment of membranes with pertussis toxin. Myometrial membranes contained two pertussis toxin substrates of 40 and 41 kDa, which corresponded immunologically to alpha-subunits of Gi-type G-proteins. The faster migrating substrate was tentatively identified as Gi2 alpha-subunit. The electrophoretic mobility of the slower migrating Gi alpha-subunit was very similar to that of the Gi3 alpha-subunit. Go alpha-subunits were not detected. Thus, in uterine smooth muscle, G-proteins of the Gi-family (Gi2, Gi3) couple high-affinity bradykinin receptors to their effector enzymes.
Liebmann
C
C
Bereich Allgemeine Biochemie, Friedrich-Schiller-Universität Jena, East Germany.
Offermanns
S
S
Spicher
K
K
Hinsch
K D
KD
Schnittler
M
M
Morgat
J L
JL
Reissmann
S
S
Schultz
G
G
Rosenthal
W
W
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000818:Animals; D001920:Bradykinin / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002772:Cholera Toxin / Q000494:pharmacology; D005260:Female; D020558:GTP Phosphohydrolases / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D009215:Myometrium / Q000378:metabolism*; D037342:Pertussis Toxin; D051381:Rats; D011919:Rats, Inbred Strains; D018002:Receptors, Bradykinin; D017981:Receptors, Neurotransmitter / Q000302:isolation & purification / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D046911:Macromolecular Substances; D018002:Receptors, Bradykinin; D017981:Receptors, Neurotransmitter; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D002772:Cholera Toxin; D037342:Pertussis Toxin; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D001920:Bradykinin