Publication Date:
2014-07-27
Description:
Serotonin (5-HT) interacts with a wide variety of 5-HT receptors (5-HTR) of which 5-HT 2A R plays an important target for antidepressant and atypical antipsychotic drugs. The carboxyl-terminal tail of 5-HT 2A R encodes a motif that mediates interactions with PSD-95/disc large/zona occludens (PDZ) domain–containing proteins. In the present study, we found that 5-HT 2A R interacts with synapse-associated protein 97 (SAP97; also known as DLG1) by coimmunoprecipitation in human embryonic 293 (HEK 293) cells and cortical brain lysates. We found that 5-HT 2A R expression results in the recruitment of SAP97 from the cytosol to the plasma membrane and that this recruitment is dependent on an intact 5-HT 2A R PDZ binding motif. We also show that 5-HT 2A R interacts with SAP97 using bioluminescence energy transfer and that overexpression of SAP97 retards 5-HT 2A R endocytosis, while single hairpin RNA knockdown facilitates 5-HT 2A R internalization. The knockdown of SAP97 in HEK 293 cells results in a reduction in the maximum efficacy for 5-HT 2A R-stimulated inositol phosphate formation and that the deletion of the 5-HT 2A R PDZ motif also impairs 5-HT 2A R signaling. Similarly to what has been observed for the corticotropin-releasing factor receptor 1 (CRFR1), SAP97 expression is essential for 5-HT 2A R-stimulated extracellular-regulated protein kinase 1/2 (ERK1/2) phosphorylation by a PDZ interaction-independent mechanism. Moreover, we find that SAP97 is not responsible for CRFR1-mediated sensitization of 5-HT 2A R signaling. Taken together, our studies show that SAP97 plays a conserved role in regulating 5-HT 2A R endocytosis and ERK1/2 signaling, but plays a novel role in regulating 5-HT 2A R G protein coupling.
Print ISSN:
0026-895X
Electronic ISSN:
1521-0111
Topics:
Chemistry and Pharmacology
,
Medicine
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