The function of SLC17A8 (solute carrier family 17 member 8, ENSG00000179520) is as follows. Multifunctional transporter that transports L-glutamate as well as multiple ions such as chloride, sodium and phosphate (PubMed:12151341, PubMed:33440152). At the synaptic vesicle membrane, mainly functions as an uniporter that mediates the uptake of L- glutamate into synaptic vesicles at presynaptic nerve terminals of excitatory neural cells (PubMed:12151341). The L-glutamate 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:12151341). 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 (By similarity). 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 (Probable). The symporter activity is electrogenic (PubMed:33440152). Moreover, operates synergistically with SLC18A3/VACHT under a constant H(+) gradient, thereby allowing striatal vesicular acetylcholine uptake (By similarity). {ECO:0000250|UniProtKB:Q7TSF2, ECO:0000269|PubMed:12151341, ECO:0000305|PubMed:33440152}.