A prostaglandin E receptor coupled to a pertussis toxin-sensitive guanine nucleotide regulatory protein in rabbit cortical collecting tubule cells
At different concentrations, prostaglandin E2 (PGE2) can either stimulate or inhibit cAMP formation in freshly isolated rabbit cortical collecting tubule (RCCT) cells, but in cultured RCCT cells PGE2 can only stimulate cAMP synthesis (Sonnenburg, W. K., and Smith W. L. (1989) J. Biol. Chem. 263, 615...
Saved in:
Published in | The Journal of biological chemistry Vol. 265; no. 15; pp. 8479 - 8483 |
---|---|
Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Bethesda, MD
American Society for Biochemistry and Molecular Biology
25.05.1990
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | At different concentrations, prostaglandin E2 (PGE2) can either stimulate or inhibit cAMP formation in freshly isolated rabbit
cortical collecting tubule (RCCT) cells, but in cultured RCCT cells PGE2 can only stimulate cAMP synthesis (Sonnenburg, W.
K., and Smith W. L. (1989) J. Biol. Chem. 263, 6155-6160). Here, we report characteristics of [3H]PGE2 binding to membrane
receptor preparations from both freshly isolated and cultured RCCT cells. [3H]PGE2 binding to membranes from freshly isolated
RCCT cells was saturable and partially reversible. Equilibrium binding analyses indicated that in the absence of guanosine
5'-3-O-(thio)triphosphate (GTP gamma S) there is a single class of PGE2 binding sites (KD = 4.2 +/- 0.4 nM; Bmax = 583 +/-
28 fmol/mg); in the presence of 100 microM GTP gamma S, there is also only one class of binding sites but with a somewhat
lower KD = 1.2 +/- 0.5 nM (Bmax = 370 +/- 40 fmol/mg). This stimulatory effect of GTP gamma S was blocked by pretreatment
of the freshly isolated RCCT cells with pertussis toxin. The relative affinities of prostanoids for the [3H]PGE2-binding site
were determined to be 17,18,19,20-tetranor-16-phenoxy-PGE2-methylsulfonylamide (sulprostone) approximately PGE2 approximately
PGE1 approximately 16,16-dimethyl-PGE2 greater than carbacyclin approximately PGF2 alpha greater than PGD2. This is the order
of potency with which prostaglandins inhibit arginine vasopressin-induced cAMP formation in fresh RCCT cells. Interestingly,
[3H]PGE2 binding to membranes from cultured cells, which, unlike fresh cells, fail to show an inhibitory response to PGE2,
was only 10-20% of that observed with membranes from fresh cells; moreover, binding of [3H]PGE2 to membranes from cultured
cells was neither stimulated by GTP gamma S nor inhibited by sulprostone. The prostanoid binding specificities and the unusual
pertussis toxin-sensitive, stimulatory effect of GTP gamma S on binding of [3H]PGE2 to membranes from freshly isolated RCCT
cells are characteristics shared by a Gi-linked PGE receptor from renal medulla (Watanabe, T., Umegaki, K., and Smith, W.
L. (1986) J. Biol. Chem. 261, 14340-14349). Our results suggest that the [3H]PGE2 binding site of freshly isolated RCCT cells
is the PGE receptor which is coupled to a Gi to attenuate arginine vasopressin-induced cAMP synthesis in the renal collecting
tubule. |
---|---|
Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0021-9258 1083-351X |
DOI: | 10.1016/S0021-9258(19)38913-6 |