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Mol Cell Neurosci. 2003 Jul;23(3):398-413.

Functional G-protein heterotrimers are associated with vesicles of putative glutamatergic terminals: implications for regulation of transmitter uptake.

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Institut für Anatomie/Neurowissenschaftliches Zentrum der Charité, Humboldt-Universität zu Berlin, Philippstrasse 12, D-10115 Berlin, Germany.

Erratum in

  • Mol Cell Neurosci. 2003 Nov;24(3):850. Nümberg, Bernd [corrected to Nürnberg, Bernd].


Changes in the vesicular transmitter content modulate synaptic strength and may contribute to synaptic plasticity. Several transporters mediating transmitter uptake into small synaptic vesicles (SSVs) have been identified but their regulation is largely unknown. Here we show by quantitative immunoelectron microscopy that the heterotrimeric G-protein subunits Galphao(2), Galpha(q/11), Gbeta(2), and Ggamma(7) are associated with vesicle-containing areas in terminals of cerebellar parallel fibers. These terminals also contain the vesicular glutamate transporter 1 (VGLUT1). In contrast, SSVs of climbing fiber terminals that contain VGLUT2 express one of the Gbeta-subunits Gbeta(1), Gbeta(3), or Gbeta(4), Ggamma(7), and one Galpha-subunit, probably Galphao(2). Glutamate uptake into cerebellar SSVs was inhibited by more than 50% by GMppNp, an activator of G proteins. Thus, vesicle populations with different subtypes of vesicular glutamate transporters contain functional G proteins with distinct subunit profiles. Heterotrimeric G proteins may play an important role in the control of vesicular filling.

[Indexed for MEDLINE]

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