Attenuated PLD1 association and signalling at the H452Y polymorphic form of the 5-HT(2A) receptor.

Zoe Barclay, Louise Dickson, Derek Robertson, Melanie Johnson, Pamela Holland, Roberta Rosie, Liting Sun, Helen Jerina, Eve Lutz, Sue Fleetwood-Walker, Rory Mitchell

Centre for Integrative Physiology, School of Biomedical Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK.

Cellular signalling 2013 Apr

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The 5-HT2A receptor (5-HT2AR) is implicated in psychotropic changes within the central nervous system (CNS). A number of polymorphisms have been reported in the 5-HT2AR gene; one of these results in a non-synonymous change, H452Y, in the carboxy-terminal tail of the receptor protein. The minor allele (9% occurrence) has been statistically associated with CNS dysfunction such as impaired memory processing and resistance to neuroleptic treatment in schizophrenic patients. We investigated the impact of H452Y mutation of the 5-HT2AR expressed in COS7 cells on distinctly coupled intracellular signalling pathways from the receptor, focusing on the heterotrimeric G protein-independent phospholipase D (PLD) pathway, compared to the conventional Gq/11-linked phospholipase C (PLC) pathway. The H452Y mutation selectively attenuated PLD signalling, which as in the wild-type receptor, was mediated by a molecular complex involving PLD1 docked to the receptor's carboxy-terminal tail domain. Co-immunoprecipitation and GST-fusion protein experiments revealed that the H452Y mutation selectively reduced PLD1 binding to the receptor. Experiments with blocking peptides to mimic short sections of the 5-HT2AR tail sequence revealed that the peptide spanning residue 452 strongly reduced PLD but not PLC responses of the receptor. Similar observations were made when assessing both PLD responses and PLD-dependent cellular proliferation elicited by activation of 5-HT2ARs natively expressed in MCF-7 cells. Overall these findings indicate that the H452Y polymorphic variant of the 5-HT2AR displays selective disruption of its PLD signalling pathway. This may potentially play a role in the CNS dysfunction associated with the H452Y allele of the 5-HT2AR. Copyright © 2013 Elsevier Inc. All rights reserved.

Citation

Zoe Barclay, Louise Dickson, Derek Robertson, Melanie Johnson, Pamela Holland, Roberta Rosie, Liting Sun, Helen Jerina, Eve Lutz, Sue Fleetwood-Walker, Rory Mitchell. Attenuated PLD1 association and signalling at the H452Y polymorphic form of the 5-HT(2A) receptor. Cellular signalling. 2013 Apr;25(4):814-21