TY - JOUR TI - Localization, proteomics, and metabolite profiling reveal a putative vesicular transporter for UDP-glucose AU - Qian, Cheng AU - Wu, Zhaofa AU - Sun, Rongbo AU - Yu, Huasheng AU - Zeng, Jianzhi AU - Rao, Yi AU - Li, Yulong A2 - Boudker, Olga A2 - Seal, Rebecca A2 - Krantz, David E VL - 10 PY - 2021 DA - 2021/07/16 SP - e65417 C1 - eLife 2021;10:e65417 DO - 10.7554/eLife.65417 UR - https://doi.org/10.7554/eLife.65417 AB - Vesicular neurotransmitter transporters (VNTs) mediate the selective uptake and enrichment of small-molecule neurotransmitters into synaptic vesicles (SVs) and are therefore a major determinant of the synaptic output of specific neurons. To identify novel VNTs expressed on SVs (thus identifying new neurotransmitters and/or neuromodulators), we conducted localization profiling of 361 solute carrier (SLC) transporters tagging with a fluorescent protein in neurons, which revealed 40 possible candidates through comparison with a known SV marker. We parallelly performed proteomics analysis of immunoisolated SVs and identified seven transporters in overlap. Ultrastructural analysis further supported that one of the transporters, SLC35D3, localized to SVs. Finally, by combining metabolite profiling with a radiolabeled substrate transport assay, we identified UDP-glucose as the principal substrate for SLC35D3. These results provide new insights into the functional role of SLC transporters in neurotransmission and improve our understanding of the molecular diversity of chemical transmitters. KW - neurotransmitters KW - transporter KW - solute carrier KW - synaptic vesicles KW - UDP-glucose JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -