A1 adenosine receptors. Two amino acids are responsible for species differences in ligand recognition.

Tucker, Amy L.; Robeva, Anna; Taylor, Heidi E.; Holeton, Diane; Bockner, M; Lynch, Kevin R.; Linden, Joel

doi:10.1016/s0021-9258(18)46872-x

Cited by 74 publications

(22 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The receptors had similar affinities for [$H]CPX, with K d values ranging between 6 and 11 nM. This is typical for the affinity of [$H]CPX reported for canine A " receptors [27]. All of the chimaeric receptors with A " TM sequences retained at least a 300-fold higher affinity for the A " selective agonist CPA than for the A #A -selective agonist CGS21680 (results not shown).…”

Section: Radioligand Binding Of Subtype-selective Ligands To Chimaeric a 1 /A 2a Adenosine Receptorsupporting

confidence: 58%

Dominance of Gs in doubly Gs/Gi-coupled chimaeric A1/A2A adenosine receptors in HEK-293 cells

TUCKER¹,

JIA²,

HOLETON³

et al. 2000

Biochem. J.

View full text Add to dashboard Cite

A(1) adenosine receptors inhibit adenylate cyclase by activating G(i)/G(o), whereas A(2A) receptors activate G(s). We examined how regions of A(1) and A(2A) receptors regulate coupling to G-proteins by constructing chimaeras in which the third intracellular loops (3ICL or L) and/or the C-termini (or T) were switched. Pertussis toxin (PTX) was used in membrane radioligand binding assays to calculate the fraction of recombinant receptors coupled to G(i)/G(o) and in whole cells to differentially influence agonist-stimulated cAMP accumulation. Switching A(1)/A(2A) 3ICL domains results in receptors that maintain binding selectivity for ligands but are doubly coupled. Receptor chimaeras with an A(1) 3ICL sequence (A(2A)/A(1)L or A(2A)/A(1)LT) respond to agonist stimulation with elevated cAMP despite being coupled predominantly to G(i)/G(o). These chimaeras have basal cAMP levels lower than those of wild-type A(2A) receptors, similar to wild-type A(1) receptors. The A(1) C-terminus modulates the coupling of receptors with A(1) 3ICL such that A(2A)/A(1)LT is better coupled to G(i)/G(o) than A(2A)/A(1)L. The C-terminus has little impact on coupling to receptors containing A(2A) 3ICL sequence. Our results show that the C-terminus sequence selectively facilitates coupling to G(i)/G(o) mediated by A(1) 3ICL and not by other intracellular domains that favour G(i) coupling. The C-terminus sequence has little or no effect on coupling to G(s). For doubly G(s)/G(i)-coupled adenosine receptors in HEK-293 cells, G(s)-mediated stimulation predominates over G(i)/G(o)-mediated inhibition of adenylate cyclase. We discuss the signalling consequences of simultaneously activating opposing G-proteins within single cells.

show abstract

Section: Radioligand Binding Of Subtype-selective Ligands To Chimaeric a 1 /A 2a Adenosine Receptorsupporting

confidence: 58%

Dominance of Gs in doubly Gs/Gi-coupled chimaeric A1/A2A adenosine receptors in HEK-293 cells

TUCKER¹,

JIA²,

HOLETON³

et al. 2000

Biochem. J.

View full text Add to dashboard Cite

show abstract

“…Previous studies of the canine A 1 R suggested that it has lower affinities compared with other species for DPCPX, KW3902, and two other xanthine derivatives, toponafylline and naxifylline, but similar affinities for CGS15943 and XAC (Table S1), and that the canine A 1 R is more similar to the A 2 subtype receptors (Martin, 1992). Another early study identified residues 7.35 and 7.42 as responsible for species difference in both agonist and antagonist binding in A 1 R (Tucker et al, 1994). This is in line with our results from mutagenesis, confirming the role of residue 7.35 in establishing ligand selectivity between A 1 and A 2A receptors (Figure 6).…”

Section: Discussionmentioning

confidence: 99%

Structures of Human A 1 and A 2A Adenosine Receptors with Xanthines Reveal Determinants of Selectivity

et al. 2017

View full text Add to dashboard Cite

The adenosine A and A receptors belong to the purinergic family of G protein-coupled receptors, and regulate diverse functions of the cardiovascular, respiratory, renal, inflammation, and CNS. Xanthines such as caffeine and theophylline are weak, non-selective antagonists of adenosine receptors. Here we report the structure of a thermostabilized human A receptor at 3.3 Å resolution with PSB36, an A-selective xanthine-based antagonist. This is compared with structures of the A receptor with PSB36 (2.8 Å resolution), caffeine (2.1 Å), and theophylline (2.0 Å) to highlight features of ligand recognition which are common across xanthines. The structures of AR and AR were analyzed to identify the differences that are important selectivity determinants for xanthine ligands, and the role of T270 in AR (M270 in AR) in conferring selectivity was confirmed by mutagenesis. The structural differences confirmed to lead to selectivity can be utilized in the design of new subtype-selective AR or AR antagonists.

show abstract

“…Natural variability by allelic variation accounts for, e.g., the pigmentation phenotypes regulated by the MSH receptor within one species [Robbins et al, 1993]. Species differences resulting from (minor) genetic variability have been documented for the human and hamster β 2 adrenoceptors [Caron et al, 1988], the rat and human serotonin 5HT 1B receptors [Parker et al, 1993], the human and rat neurokinin NK1 receptors [Jensen et al, 1994], adenosine A 3 receptors [Linden, 1994], mammalian adenosine A 1 receptors [Meng et al, 1994;Tucker et al, 1994], and primate dopamine D 4 receptors [Livak et al, 1995]. Moreover, allelic variation can result in an abundance of pathological conditions [Raymond, 1994].…”

Section: Allelic Variationsmentioning

confidence: 99%

Molecular architecture of G protein-coupled receptors

1996

View full text Add to dashboard Cite

This review of the current literature on mutations in G protein-coupled receptors (GPCRs) of the rhodopsin-related family intends to draw inferences from amino acid sequences for single receptors and multiple sequence alignments with regard to the molecular architecture of this class of receptors. For this purpose a comprehensive list of mutations within the transmembrane helical regions (TMs; over 390 mutations from 38 different receptor subtypes) and their effects on function was compiled, and an alignment of known GPCR sequences (over 150 separate sequences) was made. Regions most prominently involved in ligand binding are located in TMs 3, 5, 6, and 7. Position 3.32 in TM3 is occupied by a D in all biogenic amine receptors (sequence conservation) but may be occupied by uncharged residues in other receptors while its role in ligand binding is analogous (function conservation). TMs 5, 6, and 7 display considerable sequence conservation throughout the majority of GPCRs investigated, but not necessarily at those positions involved in ligand binding. However, considerable function conservation is observed for positions 5.42 (frequently hydrophilic), 5.46 (small amino acids required for agonist binding to "small ligand" receptors), 6.52 and 7.39 (high variability), and 7.43 (frequently aromatic). A general conclusion of this review is that there is overwhelming conservation of structure-function correlates among GPCRs. Thus, it is now possible to cross-correlate the results of mutagenesis studies between GPCRs of different subfamilies, and to use those results to predict the function of specific residues in new GPCR sequences.

show abstract

A1 adenosine receptors. Two amino acids are responsible for species differences in ligand recognition.

Cited by 74 publications

References 40 publications

Dominance of Gs in doubly Gs/Gi-coupled chimaeric A1/A2A adenosine receptors in HEK-293 cells

Dominance of Gs in doubly Gs/Gi-coupled chimaeric A1/A2A adenosine receptors in HEK-293 cells

Structures of Human A 1 and A 2A Adenosine Receptors with Xanthines Reveal Determinants of Selectivity

Molecular architecture of G protein-coupled receptors

Contact Info

Product

Resources

About