| Autor: |
Shahrooz, Nasrollahi-Shirazi, Daniel, Szöllösi, Qiong, Yang, Edin, Muratspahic, Ali, El-Kasaby, Sonja, Sucic, Thomas, Stockner, Christian, Nanoff, Michael, Freissmuth |
| Rok vydání: |
2020 |
| Předmět: |
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| Zdroj: |
Mol Pharmacol |
| ISSN: |
1521-0111 |
| Popis: |
In medium-size, spiny striatal neurons of the direct pathway, dopamine D(1)- and adenosine A(1)-receptors are coexpressed and are mutually antagonistic. Recently, a mutation in the gene encoding the A(1)-receptor (A(1)R), A(1)R-G279S(7.44), was identified in an Iranian family: two affected offspring suffered from early-onset l-DOPA–responsive Parkinson’s disease. The link between the mutation and the phenotype is unclear. Here, we explored the functional consequence of the G279S substitution on the activity of the A(1)-receptor after heterologous expression in HEK293 cells. The mutation did not affect surface expression and ligand binding but changed the susceptibility to heat denaturation: the thermodynamic stability of A(1)R-G279S(7.44) was enhanced by about 2 and 8 K when compared with wildtype A(1)-receptor and A(1)R-Y288A(7.53) (a folding-deficient variant used as a reference), respectively. In contrast, the kinetic stability was reduced, indicating a lower energy barrier for conformational transitions in A(1)R-G279S(7.44) (73 ± 23 kJ/mol) than in wild-type A(1)R (135 ± 4 kJ/mol) or in A(1)R-Y288A(7.53) (184 ± 24 kJ/mol). Consistent with this lower energy barrier, A(1)R-G279S(7.44) was more effective in promoting guanine nucleotide exchange than wild-type A(1)R. We detected similar levels of complexes formed between D(1)-receptors and wild-type A(1)R or A(1)R-G279S(7.44) by coimmunoprecipitation and bioluminescence resonance energy transfer. However, lower concentrations of agonist were required for half-maximum inhibition of dopamine-induced cAMP accumulation in cells coexpressing D(1)-receptor and A(1)R-G279S(7.44) than in those coexpressing wild-type A(1)R. These observations predict enhanced inhibition of dopaminergic signaling by A(1)R-G279S(7.44) in vivo, consistent with a pathogenic role in Parkinson’s disease. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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