The neuronal monoamine transporter VMAT2 is regulated by the trimeric GTPase Go(2).
Monoamines such as noradrenaline and serotonin are stored in secretory vesicles and released by exocytosis. Two related monoamine transporters, VMAT1 and VMAT2, mediate vesicular transmitter uptake. Previously we have reported that in the rat pheochromocytoma cell line PC 12 VMAT1, localized to peptide-containing secretory granules, is controlled by the heterotrimeric G-protein Go(2). We now show that in BON cells, a human serotonergic neuroendocrine cell line derived from a pancreatic tumor expressing both transporters on large, dense-core vesicles, VMAT2 is even more sensitive to G-protein regulation than VMAT1. The activity of both transporters is only downregulated by Galphao(2), whereas comparable concentrations of Galphao(1) are without effect. In serotonergic raphe neurons in primary culture VMAT2 is also downregulated by pertussis toxin-sensitive Go(2). By electron microscopic analysis from prefrontal cortex we show that VMAT2 and Galphao(2) associate preferentially to locally recycling small synaptic vesicles in serotonergic terminals. In addition, Go(2)-dependent modulation of VMAT2 also works when using a crude synaptic vesicle preparation from this brain area. We conclude that regulation of monoamine uptake by the heterotrimeric G proteins is a general feature of monoaminergic neurons that controls the content of both large, dense-core and small synaptic vesicles.
Höltje
M
M
Institut für Anatomie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany.
von Jagow
B
B
Pahner
I
I
Lautenschlager
M
M
Hörtnagl
H
H
Nürnberg
B
B
Jahn
R
R
Ahnert-Hilger
G
G
D000818:Animals; D002276:Carcinoid Tumor; D002463:Cell Membrane Permeability / Q000502:physiology; D015536:Down-Regulation / Q000502:physiology; D044385:GTP-Binding Protein alpha Subunits; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism*; D006632:Histamine / Q000493:pharmacokinetics; D006801:Humans; D008562:Membrane Glycoproteins / Q000032:analysis / Q000378:metabolism*; D026901:Membrane Transport Proteins; D016253:Microscopy, Immunoelectron; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000737:chemistry / Q000201:enzymology* / Q000648:ultrastructure; D009479:Neuropeptides; D016716:PC12 Cells; D010190:Pancreatic Neoplasms; D011817:Rabbits; D011903:Raphe Nuclei / Q000166:cytology; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012701:Serotonin / Q000493:pharmacokinetics; D014316:Tritium; D014407:Tumor Cells, Cultured; D050492:Vesicular Biogenic Amine Transport Proteins; D050493:Vesicular Monoamine Transport Proteins
D044385:GTP-Binding Protein alpha Subunits; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009479:Neuropeptides; D011993:Recombinant Fusion Proteins; C493449:SLC18A1 protein, human; C493452:SLC18A2 protein, human; C493451:Slc18a1 protein, rat; C493454:Slc18a2 protein, rat; D050492:Vesicular Biogenic Amine Transport Proteins; D050493:Vesicular Monoamine Transport Proteins; C084618:olfactory G protein subunit alpha olf; D014316:Tritium; D012701:Serotonin; D006632:Histamine; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D020962:Heterotrimeric GTP-Binding Proteins