Kamiya Toshio, Saitoh Osamu, Nakata Hiroyasu
Department of Molecular Cell Signaling, Tokyo Metropolitan Institute for Neuroscience, Japan.
Cell Struct Funct. 2005 Feb;29(5-6):139-45. doi: 10.1247/csf.29.139.
The direct homo- and heteromeric association between G-protein-coupled receptors (GPCRs), adenosine A2A receptor (A(2A)R) and dopamine D2 receptor (D2R), occurs although little is known about the selectivity of their formation (A(2A)R/A(2A)R vs. A(2A)R/D2R). In order to stimulate the heteromerization of A(2A)R and D2R, we have designed a single-polypeptide-chain heterodimeric A(2A)R/D2R complex by fusing the C-terminus of the A(2A)R via transmembrane (TM) of a type II TM protein with the N-terminus of D2R in tandem. This was successfully expressed on the cell surface as a full-length protein with specific binding to the respective ligands and functional coupling to G-proteins comparable to wild-type receptors, suggesting the possible creation of physiologically relevant heteromeric A(2A)R/D2R. This expression system would be useful to exclusively clarify the properties of heteromeric GPCRs irrespective of homomeric receptors.
G蛋白偶联受体（GPCRs）中的腺苷A2A受体（A(2A)R）和多巴胺D2受体（D2R）之间存在直接的同源和异源二聚体结合，尽管对它们形成的选择性（A(2A)R/A(2A)R与A(2A)R/D2R）了解甚少。为了促进A(2A)R和D2R的异源二聚化，我们通过将A(2A)R的C末端经由II型跨膜蛋白的跨膜区（TM）与D2R的N末端串联融合，设计了一种单多肽链异源二聚体A(2A)R/D2R复合物。该复合物成功地在细胞表面表达为全长蛋白，与各自的配体具有特异性结合，并与G蛋白进行功能性偶联，与野生型受体相当，这表明可能产生了生理相关的异源A(2A)R/D2R。该表达系统将有助于专门阐明异源GPCRs的特性，而不受同源受体的影响。
