Molecular Biology of Angiotensin II Receptors

Lassègue, Bernard; Griendling, Kathy K.; Alexander, R. Wayne

doi:10.1007/978-1-4615-2464-9_2

Cited by 14 publications

(16 citation statements)

References 150 publications

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“…Although this observation may appear difficult to reconcile with our finding, the cell specificity could account for such differences. There are many different CHO cell lines available and cell-specific alterations in Ang II receptor expression and function have been well documented [11,16]. We also observed differences in the profile of agonist-stimulated calcium transients between j3h-UTR and k3h-UTR expressing cells.…”

Section: Discussionsupporting

confidence: 55%

“…We report, in the present study, that the AT "A receptor without its 3h-UTR, when transfected into CHO-K1 cells, couples to cAMP stimulation and inhibition of DNA synthesis. In contrast, when transfected with its 3h-UTR, the AT "A did not couple to these two responses, which has been observed in many tissues and cells where native (j3h-UTR) receptors are expressed in reponse to Ang II [11,12,16]. Previously, in CHO-K1 cells overexpressing the AT "A (k3h-UTR) we demonstrated that the stimulation of cAMP is concentrationand time-dependent (EC &!…”

Section: Discussionmentioning

confidence: 94%

“…Data were analysed and non-linear regression curves were obtained using the computer software Prism (GraphPAD software, San Diego, CA, U.S.A.) ; K d and B max were calculated as described previously [19]. High-affinity agonist binding requires association of the receptor and the heterotrimeric G-protein with the α-subunit in the GDP-bound form [11,16]. The ability of plasma membrane AT "A receptors to couple to G-proteins was determined using GTP[S], a non-hydrolysable GTP analogue which lowers the affinity of the receptor for Ang II.…”

Section: Receptor-binding Studiesmentioning

confidence: 99%

“…Ang II also appears to participate in mediating numerous other actions, including fetal development, cell growth (normal and pathophysiological), neuromodulation and cytokine-like effects [11]. These actions of Ang II are mediated by two major types of Ang II receptors, AT " and AT # , which are both putative members of the seven transmembrane G-protein coupled receptor superfamily [11,12].…”

Section: Introductionmentioning

confidence: 99%

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Functional role for the angiotensin II receptor (AT1A) 3′-untranslated region in determining cellular responses to agonist: evidence for recognition by RNA binding proteins

Thekkumkara

Gruber

Motel

et al. 1998

Biochemical Journal

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We demonstrate a functional role for the 3ʹ-untranslated region (3ʹ-UTR) of the angiotensin II (Ang II) receptor subtype AT1A mRNA in Chinese hamster ovary (CHO-K1) cells by stably transfecting the coding region of the receptor gene with or without the 845 bp 3ʹ-UTR. Two cell lines expressing similar levels of cell-surface receptors (with 3ʹ-UTR, Bmax = 571 fmol/mg protein; without 3ʹ-UTR, Bmax = 663 fmol/mg protein) were used in the present study. Both cell lines expressed high-affinity receptors (with 3ʹ-UTR, Kd = 0.83 nM; without 3ʹ-UTR, Kd = 0.82 nM), and binding studies with 125I-labelled Ang II in the presence of GTP[S] demonstrated that both coupled to heterotrimeric G-proteins. Despite these similarities, significant differences were observed for receptor-mediated cell signalling pathways. In cells without the 3ʹ-UTR, Ang II stimulated an increase in cAMP accumulation (11-fold above control) and in cells with the 3ʹ-UTR no stimulation was observed, which was consistent with previous observations in most endogenous Ang II receptor (AT1)-expressing cells. Activation of cAMP by Ang II in cells without the 3ʹ-UTR correlated with an inhibition of DNA synthesis, determined by [3H]thymidine incorporation. Ang II-mediated responses were blocked by EXP3174, a selective non-peptide receptor antagonist. We also observed differences in the transient profiles of intracellular calcium between cells with and without the 3ʹ-UTR in response to Ang II. In cells with the 3ʹ-UTR, a sustained level of intracellular calcium was observed after Ang II stimulation, whereas cells without the 3ʹ-UTR displayed a full return to basal level within 50 s of Ang II treatment. Even though the expressed exogenous gene is under the control of a constitutively expressing promoter (cytomegalovirus promoter), Northern-blot analysis revealed a considerably greater accumulation of AT1A mRNA in cells without the 3ʹ-UTR compared with cells with the 3ʹ-UTR. Analysis of the decay rate of the AT1A mRNA in cells with and without the 3ʹ-UTR revealed that the normally unstable AT1A receptor mRNA became highly stable by removing its 3ʹ-UTR, identifying a role for the 3ʹ-UTR in mRNA destabilization. Interestingly, both cells express similar levels of receptors at the cell surface, suggesting that the 3ʹ-UTR is also involved in the efficient translation and/or translocation of the receptor protein to the plasma membrane. We hypothesized that these 3ʹ-UTR-mediated functions of the receptor are regulated by RNA-binding proteins. To identify possible RNA-binding proteins for the AT1A 3ʹ-UTR, cellular extracts were prepared from parental CHO-K1 cells and 3ʹ-UTR-binding assays, electrophoretic mobility-shift assays and UV crosslinking studies were performed. A major cellular protein of 55 kDa was identified, which specifically interacted with the 3ʹ-UTR. Our data suggest that the 3ʹ-UTR of the AT1A can control specific receptor functions, perhaps via selective recognition of the 3ʹ-UTR by RNA-binding proteins.

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Section: Discussionsupporting

confidence: 55%

Section: Discussionmentioning

confidence: 94%

Section: Receptor-binding Studiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Functional role for the angiotensin II receptor (AT1A) 3′-untranslated region in determining cellular responses to agonist: evidence for recognition by RNA binding proteins

Thekkumkara

Gruber

Motel

et al. 1998

Biochemical Journal

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“…Although most of the physiological responses to AngII are mediated by AT 1 receptors (29), the postreceptor mechanisms appear to differ among various vascular beds. Recent studies indicate that AngII transduces its signal with second messengers synthesized by phospholipase C in arterial smooth muscle (29). However, Ohya and Sperelakis (30) have demonstrated that AngII gates calcium channels by coupling with G protein in the portal vein.…”

Section: Discussionmentioning

confidence: 99%

Cellular mechanisms mediating rat renal microvascular constriction by angiotensin II.

Takenaka¹,

Suzuki²,

Fujiwara³

et al. 1997

J. Clin. Invest.

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To assess cellular mechanisms mediating afferent (AA) and efferent arteriolar (EA) constriction by angiotensin II (AngII), experiments were performed using isolated perfused hydronephrotic kidneys. In the first series of studies, AngII (0.3 nM) constricted AAs and EAs by 29 Ϯ 3 ( n ϭ 8, P Ͻ 0.01) and 27 Ϯ 3% ( n ϭ 8, P Ͻ 0.01), respectively. Subsequent addition of nifedipine restored AA but not EA diameter. Manganese (8 mM) reversed EA constriction by 65 Ϯ 9% ( P Ͻ 0.01). In the second group, the addition of N -ethylmaleimide (10 M), a Gi/Go protein antagonist, abolished AngIIinduced EA ( n ϭ 6) but not AA constriction ( n ϭ 6). In the third series of experiments, treatment with 2-nitro-4-carboxyphenyl-N , N -diphenyl-carbamate (200 M), a phospholipase C inhibitor, blocked both AA and EA constriction by AngII ( n ϭ 6 for each). In the fourth group, thapsigargin (1 M) prevented AngII-induced AA constriction ( n ϭ 8) and attenuated EA constriction (8 Ϯ 2% decrease in EA diameter at 0.3 nM AngII, n ϭ 8, P Ͻ 0.05). Subsequent addition of manganese (8 mM) reversed EA constriction. Our data provide evidence that in AAs, AngII stimulates phospholipase C with subsequent calcium mobilization that is required to activate voltage-dependent calcium channels. Our results suggest that AngII constricts EAs by activating phospholipase C via the Gi protein family, thereby eliciting both calcium mobilization and calcium entry. ( J.

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