Adenosine deaminase interacts with A1 adenosine receptors in pig brain cortical membranes.
Adenosine deaminase is an enzyme of purine metabolism that has largely been considered to be cytosolic. A few years ago, adenosine deaminase was reported to appear on the surface of cells. Recently, it has been demonstrated that adenosine deaminase interacts with a type II membrane protein known as either CD26 or dipeptidylpeptidase IV. In this study, by immunoprecipitation and affinity chromatography it is shown that adenosine deaminase and A1 adenosine receptors interact in pig brain cortical membranes. This is the first report in brain demonstrating an interaction between a degradative ectoenzyme and the receptor whose ligand is the enzyme substrate. By means of this interaction adenosine deaminase leads to the appearance of the high-affinity site of the receptor, which corresponds to the receptor-G protein complex. Thus, it seems that adenosine deaminase is necessary for coupling A1 adenosine receptors to heterotrimeric G proteins.
Saura
C
C
Departament de Bioquímica i Biologia Molecular, Facultat de Química, Universitat de Barcelona, Catalonia, Spain.
Ciruela
F
F
Casadó
V
V
Canela
E I
EI
Mallol
J
J
Lluis
C
C
Franco
R
R
D000243:Adenosine Deaminase / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology / Q000648:ultrastructure; D002540:Cerebral Cortex / Q000737:chemistry / Q000166:cytology / Q000201:enzymology*; D007700:Kinetics; D008969:Molecular Sequence Data; D010660:Phenylisopropyladenosine / Q000494:pharmacology; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D018047:Receptors, Purinergic P1 / Q000378:metabolism*; D013552:Swine; D014316:Tritium; D014970:Xanthines / Q000494:pharmacology
D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D018047:Receptors, Purinergic P1; D014970:Xanthines; D014316:Tritium; D010660:Phenylisopropyladenosine; C051360:1,3-dipropyl-8-cyclopentylxanthine; D000243:Adenosine Deaminase