Title : Biochemical and pharmacological study of N-linked glycosylation of the human serotonin
5-HT₇a receptor
Abstract :
- The 5-hydroxytryptamine (5-HT)(7 (a)) receptor is a G-protein-coupled receptor critically involved in human psychiatric and neurological disorders
- In the present study, we evaluate the presence and the functional role of N-glycosylation of the human 5-HT(7 ) receptor
- Western blot analysis of HEK293T cells transiently expressing the 5-HT(7 (a)) receptor in the presence of tunicamycin gave rise to a band shift, indicating the existence of an N-glycosylated form of the 5-HT(7 (a)) receptor
- To further investigate this, we mutated the two predicted N-glycosylation sites (N5Q and N66Q) and compared the molecular mass of the immunoreactive bands with those of the wild-type receptor , indicating that both asparagines were N-glycosylated
- The mutant receptors had the same binding affinity for [(3) H]5-CT and the same potency and efficacy with regard to 5-HT-induced activation of adenylyl cyclase
- However, there was a reduction in maximal ligand binding for the single and double mutants compared to the wild-type receptor
- Next, membrane labelling and immunocytochemical studies demonstrated that the N-glycosylation mutants were expressed at the cell surface
- We conclude that N-glycosylation is not important for cell surface expression of the 5-HT(7 ) receptor