Modulation of 5-HT3 receptor-mediated response and trafficking by activation of protein kinase C.
Modulation of neurotransmitter-gated membrane ion channels by protein kinase C (PKC) has been the subject of a number of studies. However, less is known about PKC modulation of the serotonin type 3 (5-HT3) receptor, a ligand-gated membrane ion channel that can mediate fast synaptic transmission in the central and peripheral nervous system. Here, we show that PKC potentiated 5-HT3 receptor-mediated current in Xenopus oocytes expressing 5-HT3A receptors and mouse N1E-115 neuroblastoma cells. In addition, using a specific antibody directed to the extracellular N-terminal domain of the 5-HT3A receptor, treatment with the PKC activator, 4 beta-phorbol 12-myristate 13-acetate (PMA), significantly increased surface immunofluorescence. PKC also increased the amount of 5-HT3A receptor protein in the cell membrane without affecting the amount receptor protein in the total cell extract. The magnitude of PMA potentiation of 5-HT3A receptor-mediated responses is correlated with the magnitude of PMA enhancement of the receptor abundance in the cell surface membrane. PMA potentiation is unlikely to occur via direct phosphorylation of the 5-HT3A receptor protein since the potentiation was not affected by point mutation of each of the putative sites for PKC phosphorylation. However, preapplication of phalloidin, which stabilizes the actin polymerization, significantly inhibited PMA potentiation of 5-HT-activated responses in both N1E-115 cells and oocytes expressing 5-HT3A receptors. On the other hand, latrunculin-A, which destabilizes actin cytoskeleton, enhanced the PMA potentiation of 5-HT3A receptors. The observations suggest that PKC can modulate 5-HT3A receptor function and trafficking through an F-actin-dependent mechanism.
Sun
Hui
H
Laboratory of Molecular and Cellular Neurobiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland 20892-8115, USA.
Hu
Xian-Qun
XQ
Moradel
Edgar M
EM
Weight
Forrest F
FF
Zhang
Li
L
D000199:Actins / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry; D002462:Cell Membrane / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D004594:Electrophysiology; D004789:Enzyme Activation; D006801:Humans; D007477:Ions; D051379:Mice; D008856:Microscopy, Fluorescence; D009154:Mutation; D009865:Oocytes / Q000378:metabolism; D010590:Phalloidine / Q000737:chemistry; D010766:Phosphorylation; D017354:Point Mutation; D011493:Protein Kinase C / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D018075:RNA, Complementary / Q000378:metabolism; D011985:Receptors, Serotonin / Q000737:chemistry* / Q000378:metabolism; D044406:Receptors, Serotonin, 5-HT3; D013755:Tetradecanoylphorbol Acetate; D013844:Thiazoles / Q000737:chemistry; D053778:Thiazolidines; D013997:Time Factors; D014407:Tumor Cells, Cultured; D014981:Xenopus; D014982:Xenopus laevis
D000199:Actins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D007477:Ions; D018075:RNA, Complementary; D011985:Receptors, Serotonin; D044406:Receptors, Serotonin, 5-HT3; D013844:Thiazoles; D053778:Thiazolidines; D010590:Phalloidine; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; C037067:latrunculin A