Glutamate loading of synaptic vesicles requires moderate Cl− concentrations, but is inhibited by high Cl−. Here, Schenck et al. show that the glutamate transporter VGLUT1 is itself a chloride channel. Although high extravesicular Cl− inhibited glutamate import through a competitive mechanism, high intravesicular Cl− concentrations enhanced glutamate import. This suggests that, in addition to the pH gradient, VGLUT1 can also utilize a steep Cl− gradient to drive glutamate transport.
- Stephan Schenck
- Sonja M Wojcik
- Shigeo Takamori