A membrane network of receptors and enzymes for adenine nucleotides and nucleosides.
Most cells express more than one receptor plus degrading enzymes for adenine nucleotides or nucleosides, and cellular responses to purines are rarely compatible with the actions of single receptors. Therefore, these receptors are viewed as components of a combinatorial receptor web rather than self-dependent entities, but it remained unclear to what extent they can associate with each other to form signalling units. P2Y(1), P2Y(2), P2Y(12), P2Y(13), P2X(2), A(1), A(2A) receptors and NTPDase1 and -2 were expressed as fluorescent fusion proteins which were targeted to membranes and signalled like the unlabelled counterparts. When tested by FRET microscopy, all the G protein-coupled receptors proved able to form heterooligomers with each other, and P2Y(1), P2Y(12), P2Y(13), A(1), A(2A), and P2X(2) receptors also formed homooligomers. P2Y receptors did not associate with P2X, but G protein-coupled receptors formed heterooligomers with NTPDase1, but not NTPDase2. The specificity of prototypic interactions (P2Y(1)/P2Y(1), A(2A)/P2Y(1), A(2A)/P2Y(12)) was corroborated by FRET competition or co-immunoprecipitation. These results demonstrate that G protein-coupled purine receptors associate with each other and with NTPDase1 in a highly promiscuous manner. Thus, purinergic signalling is not only determined by the expression of receptors and enzymes but also by their direct interaction within a previously unrecognized multifarious membrane network.
Schicker
Klaus
K
Institute of Pharmacology, Medical University of Vienna, Waehringerstrasse 13a, A-1090 Vienna, Austria.
Hussl
Simon
S
Chandaka
Giri K
GK
Kosenburger
Kristina
K
Yang
Jae-Won
JW
Waldhoer
Maria
M
Sitte
Harald H
HH
Boehm
Stefan
S
D000227:Adenine Nucleotides / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D001081:Apyrase / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology*; D005453:Fluorescence; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D006868:Hydrolysis; D047468:Immunoprecipitation; D008564:Membrane Potentials; D051379:Mice; D009705:Nucleosides / Q000378:metabolism*; D011485:Protein Binding; D021122:Protein Subunits / Q000378:metabolism; D051381:Rats; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D011983:Receptors, Purinergic / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015203:Reproducibility of Results
D000227:Adenine Nucleotides; D015703:Antigens, CD; D009705:Nucleosides; D021122:Protein Subunits; D043562:Receptors, G-Protein-Coupled; D011983:Receptors, Purinergic; D011993:Recombinant Fusion Proteins; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D001081:Apyrase; C067869:CD39 antigen