Cytoskeletal protein 4.1G binds to the third intracellular loop of the A1 adenosine receptor and inhibits receptor action.
To identify binding partners of the A1AR (A1 adenosine receptor), yeast two-hybrid screening of a rat embryonic cDNA library was performed. This procedure led to the identification of erythrocyte membrane cytoskeletal protein (represented as 4.1G) as an A1AR-binding partner. Truncation studies revealed that the C-terminal domain of 4.1G was essential for binding to A1ARs and that the C-terminal domain of 4.1G and the third intracellular loop of A1ARs interacted. A1AR-4.1G interaction was also confirmed in studies using brain tissue. Studies in HEK-293 (human embryonic kidney 293) cells and Chinese-hamster ovary cells showed that 4.1G interfered with A1AR signal transduction, as 4.1G reduced A1AR-mediated inhibition of cAMP accumulation and intracellular calcium release. 4.1G also altered cell-surface A1AR expression. These observations identify 4.1G as a novel A1AR-binding partner that can regulate adenosine action.
Lu
Dongcheng
D
Department of Pediatrics, Yale Child Health Research Center, Yale University School of Medicine, New Haven, CT, USA.
Yan
Henglin
H
Othman
Timothy
T
Turner
Christopher P
CP
Woolf
Thomas
T
Rivkees
Scott A
SA
D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D016466:CHO Cells; D020013:Calcium Signaling; D002460:Cell Line; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D008297:Male; D008958:Models, Molecular; D017434:Protein Structure, Tertiary; D051381:Rats; D017207:Rats, Sprague-Dawley; D043682:Receptor, Adenosine A1 / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D003598:Cytoskeletal Proteins; C480491:Epb41l2 protein, rat; D043682:Receptor, Adenosine A1; D000242:Cyclic AMP