Slc17a7
Developmental stage
Expression of isoform 2 increases sharply during the first ten days of postnatal life, and also increases with increasing numbers of rhodopsin cells in the retina.
Function
Multifunctional transporter that transports L-glutamate as well as multiple ions such as chloride, proton, potassium, sodium and phosphate (PubMed:10938000, PubMed:11001057, PubMed:11698619, PubMed:18080752, PubMed:19169251, PubMed:25433636, PubMed:27133463, PubMed:29642010, PubMed:33440152, PubMed:8202535). At the synaptic vesicle membrane, mainly functions as an uniporter which transports preferentially L-glutamate but also phosphate from the cytoplasm into synaptic vesicles at presynaptic nerve terminals of excitatory neural cells (PubMed:10938000, PubMed:11001057, PubMed:11698619, PubMed:18080752, PubMed:29642010). The L-glutamate or phosphate uniporter activity is electrogenic and is driven by the proton electrochemical gradient, mainly by the electrical gradient established by the vacuolar H(+)-ATPase across the synaptic vesicle membrane (PubMed:29642010). In addition, functions as a chloride channel that allows a chloride permeation through the synaptic vesicle membrane that affects the proton electrochemical gradient and promotes synaptic vesicles acidification (PubMed:10938000, PubMed:19169251, PubMed:25433636, PubMed:27133463, PubMed:29642010). Moreover, may function as a K(+)/H(+) antiport allowing to maintain the electrical gradient and to decrease chemical gradient and therefore sustain vesicular glutamate uptake (PubMed:25433636). The vesicular K(+)/H(+) antiport activity is electroneutral (PubMed:25433636). At the plasma membrane, following exocytosis, functions as a symporter of Na(+) and phosphate from the extracellular space to the cytoplasm allowing synaptic phosphate homeostasis regulation (PubMed:29642010, PubMed:33440152, PubMed:8202535). The symporter activity is driven by an inside negative membrane potential and is electrogenic (PubMed:29642010). Is necessary for synaptic signaling of visual-evoked responses from photoreceptors (By similarity).
Sequence Similarities
Belongs to the major facilitator superfamily. Sodium/anion cotransporter family. VGLUT subfamily.
Tissue Specificity
Expressed in the cerebellum, cerberal cortex and hippocampus. Isoform 2 is expressed specifically in retina.
Cellular localization
- Cytoplasmic vesicle
- Secretory vesicle
- Synaptic vesicle membrane
- Cell membrane
- Multi-pass membrane protein
- Synapse
- Synaptosome
Alternative names
Bnpi, Vglut1, Vesicular glutamate transporter 1, VGluT1, Brain-specific Na(+)-dependent inorganic phosphate cotransporter, Solute carrier family 17 member 7