Identification of Regions in the Human Angiotensin II Receptor Type 1 Responsible for Gi and Gq Coupling by Mutagenesis Study

Shibata, Takeshi; Suzuki, Chise; Ohnishi, Junji; Murakami, Kazuo; Miyazaki, Hitoshi

doi:10.1006/bbrc.1996.0067

Cited by 54 publications

(57 citation statements)

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“…Using sitedirected mutagenesis, AT 1 /AT 2 chimerae, or other approaches, it has been possible to unambiguously localize the sequences involved in G q/11 protein coupling in the i3 loop and more precisely in its proximal and distal segments (10,11). The possibility that the i2 loop of AT 1 and the proximal segment of the C-terminal tail contain sequences involved in the coupling to G q/11 protein or, more probably, G i protein is more controversial (9,38). However, like for many other G protein-coupled receptors, it seems that the acquisition of the active conformation of the AT 1 receptor results from the general arrangement of numerous discrete sequences.…”

Section: Discussionmentioning

confidence: 99%

The C-terminal Third Intracellular Loop of the Rat AT1A Angiotensin Receptor Plays a Key Role in G Protein Coupling Specificity and Transduction of the Mitogenic Signal

Conchon¹,

Barrault²,

Miserey³

et al. 1997

Journal of Biological Chemistry

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Section: Discussionmentioning

confidence: 99%

The C-terminal Third Intracellular Loop of the Rat AT1A Angiotensin Receptor Plays a Key Role in G Protein Coupling Specificity and Transduction of the Mitogenic Signal

Conchon¹,

Barrault²,

Miserey³

et al. 1997

Journal of Biological Chemistry

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“…The COOH-terminal domain of some GPCRs plays an important role in G protein isotype selectivity (11,12). At least four isoforms of the prostaglandin EP3 receptor, differing only at their COOH-terminal tails (produced by alternative splicing), couple to different G proteins to activate different second messenger systems (13,14).…”

Section: Oxytocin (Ot)mentioning

confidence: 99%

“…The COOH terminus of the human parathyroid hormone receptor directs the receptor toward an interaction with G s , whereas a core region composed of the first, second, and third intracellular loops can interact promiscuously with different G proteins (11). A truncated human AT1 receptor mutant lacking the carboxyl-terminal 50 residues is deficient in coupling to G i , but it retains full ability to bind to G q (12).…”

Section: Oxytocin (Ot)mentioning

confidence: 99%

“…The juxtamembrane portions of cytoplasmic loop 3 and cytoplasmic loop 2 of several family members have been implicated in receptor-G protein interactions. In addition, the COOH-terminal region of adrenergic receptors (3, 4) and other receptor types (5-7) is also required for G protein interactions, but this domain does not appear to be important for receptor function of all GPCR family members (8 -10).The COOH-terminal domain of some GPCRs plays an important role in G protein isotype selectivity (11,12). At least four isoforms of the prostaglandin EP3 receptor, differing only at their COOH-terminal tails (produced by alternative splicing), couple to different G proteins to activate different second messenger systems (13,14).…”

mentioning

confidence: 99%

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The Proximal Portion of the COOH Terminus of the Oxytocin Receptor Is Required for Coupling to Gq, but Not Gi

Hoare

Copland

Straková

et al. 1999

Journal of Biological Chemistry

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As the oxytocin receptor plays a key role in parturition and lactation, there is considerable interest in defining its structure/functional relationships. We previously showed that the rat oxytocin receptor transfected into Chinese hamster ovary cells was coupled to both G q/11 and G i/o , and that oxytocin stimulated ERK-2 phosphorylation and prostaglandin E 2 synthesis via protein kinase C activity. In this study, we show that deletion of 51 amino acid residues from the carboxyl terminus resulted in reduced affinity for oxytocin and a corresponding rightward shift in the dose-response curve for oxytocin-stimulated [Ca 2؉ ] i . However, oxytocin-stimulated ERK-2 phosphorylation and prostaglandin E 2 synthesis did not occur in cells expressing the truncated receptor. Oxytocin also failed to increase phospholipase A activity or activate protein kinase C, indicating that the mutant receptor is uncoupled from G q -mediated pathways. The ⌬51 receptor is coupled to G i , as oxytocin-stimulated Ca 2؉ transients were inhibited by pertussis toxin, and a G␤␥ sequestrant. Preincubation of ⌬51 cells with the tyrosine kinase inhibitor, genistein, also blocked the oxytocin effect. A ⌬39 mutant had all the activities of the wild type oxytocin receptor. These results show that the portion between 39 and 51 residues from the COOH terminus of the rat oxytocin receptor is required for interaction with G q/11 , but not G i/o . Furthermore, an increase in intracellular calcium was generated via a G i ␤␥-tyrosine kinase pathway from intracellular stores that are distinct from G q -mediated inositol trisphosphate-regulated stores. Oxytocin (OT)1 is a nine-amino acid peptide that stimulates uterine smooth muscle and mammary myoepithelial cell contraction, and prostaglandin production by uterine endometrial and amnion cells. Nucleic acid sequencing of cDNA clones of the oxytocin receptor (OTR) indicated that it is a member of the G protein-coupled receptor (GPCR) superfamily (1). As OT plays a pivotal role in parturition and lactation, there is considerable interest in defining the structure of the OTR. It has been shown for a number of GPCRs that several regions in the cytoplasmic domains contribute directly or indirectly to G protein coupling (see Ref. 2 for a review). The juxtamembrane portions of cytoplasmic loop 3 and cytoplasmic loop 2 of several family members have been implicated in receptor-G protein interactions. In addition, the COOH-terminal region of adrenergic receptors (3, 4) and other receptor types (5-7) is also required for G protein interactions, but this domain does not appear to be important for receptor function of all GPCR family members (8 -10).The COOH-terminal domain of some GPCRs plays an important role in G protein isotype selectivity (11,12). At least four isoforms of the prostaglandin EP3 receptor, differing only at their COOH-terminal tails (produced by alternative splicing), couple to different G proteins to activate different second messenger systems (13,14). The COOH terminus of the human parathyroid h...

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“…Included in these evaluations was the Glu/Asp-ArgTyr residue triplet (the "E/DRY motif"), which is highly conserved at the boundary between the third transmembrane segment and the second intracellular loop of many class I GPCRs. It has been postulated to play an important role in the transition between conformational states of some of these receptors (10,22,26).We have studied sequential deletions of residues within the predicted first, second, and third intracellular loop domains of the motilin receptor and have utilized alanine, phenylalanine, and histidine replacement for each residue within functionally important segments. Tyr66, Arg136, and Val299 were found to be critical for biological responses to both motilin and erythromycin.…”

mentioning

confidence: 99%

Mutational analysis of predicted intracellular loop domains of human motilin receptor

Tokunaga¹,

Matsuura²,

Dong

et al. 2008

American Journal of Physiology-Gastrointestinal and Liver Physi

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Motilin and erythromycin, two chemically distinct full agonists of the motilin receptor, are known to bind to distinct regions of this receptor, based on previous systematic mutagenesis of extracellular regions that dissociated the effects on these two agents. In the present work, we examined the predicted intracellular loop regions of this receptor for effects on motilin-and erythromycin-stimulated activity. We prepared motilin receptor constructs that included sequential deletions throughout the predicted first, second, and third intracellular loops, as well as replacing the residues in key regions with alanine, phenylalanine, or histidine. Each construct was transiently expressed in COS cells and characterized for motilin-and erythromycin-stimulated intracellular calcium responses and for motilin binding. Deletions of receptor residues 63-66, 135-137, and 296 -301 each resulted in substantial loss of intracellular calcium responses to stimulation by both motilin and erythromycin. Constructs with mutations of residues Tyr66, Arg136, and Val299 were responsible for the negative impact on biological activity stimulated by both agonists. These data suggest that action by different chemical classes of agonists that are known to interact with distinct regions of the motilin receptor likely yield a common activation state of the cytosolic face of this receptor that is responsible for interaction with its G protein. The identification of functionally important residues in the predicted cytosolic face provides strong candidates for playing roles in receptor-G protein interaction.erythromycin; G protein-coupled receptor; mutagenesis MOTILIN, a 22-residue peptide hormone, is secreted by endocrine cells of the intestinal mucosa. It plays an important role in the regulation of gastrointestinal motility, stimulating gastric emptying and initiating the interdigestive migrating motor complex. Agonists acting at the motilin receptor hold promise as a new class of drugs for the therapy of various gastrointestinal dysmotility states. However, the molecular basis for the binding of motilin and the nonpeptidyl agonist erythromycin to the motilin receptor and for the activation of that receptor has not been fully examined. A clear understanding of these events can provide insights that could be useful in the rational development and refinement of drugs acting at this important receptor.The motilin receptor belongs to the class I family of guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs), which also includes growth hormone secretagogue receptors (9). We recently reported (8, 16) affinity labeling of this receptor with photolabile motilin analogs with sites of covalent attachment through ligand positions 1 and 5. Both probes labeled receptor residues predicted to reside within extracellular loop regions of this receptor. We also used mutagenesis to identify critical residues within the predicted extracellular perimembranous loop and tail regions of this receptor (17,18). These residues were shown to be critic...

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Identification of Regions in the Human Angiotensin II Receptor Type 1 Responsible for Gi and Gq Coupling by Mutagenesis Study

Cited by 54 publications

References 0 publications

The C-terminal Third Intracellular Loop of the Rat AT1A Angiotensin Receptor Plays a Key Role in G Protein Coupling Specificity and Transduction of the Mitogenic Signal

The C-terminal Third Intracellular Loop of the Rat AT1A Angiotensin Receptor Plays a Key Role in G Protein Coupling Specificity and Transduction of the Mitogenic Signal

The Proximal Portion of the COOH Terminus of the Oxytocin Receptor Is Required for Coupling to Gq, but Not Gi

Mutational analysis of predicted intracellular loop domains of human motilin receptor

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