RT Journal Article SR Electronic T1 Super-resolution imaging reveals the nanoscale organization of metabotropic glutamate receptors at presynaptic active zones JF Science Advances JO Sci Adv FD American Association for the Advancement of Science SP eaay7193 DO 10.1126/sciadv.aay7193 VO 6 IS 16 A1 Siddig, Sana A1 Aufmkolk, Sarah A1 Doose, Sören A1 Jobin, Marie-Lise A1 Werner, Christian A1 Sauer, Markus A1 Calebiro, Davide YR 2020 UL http://advances.sciencemag.org/content/6/16/eaay7193.abstract AB G protein–coupled receptors (GPCRs) play a fundamental role in the modulation of synaptic transmission. A pivotal example is provided by the metabotropic glutamate receptor type 4 (mGluR4), which inhibits glutamate release at presynaptic active zones (AZs). However, how GPCRs are organized within AZs to regulate neurotransmission remains largely unknown. Here, we applied two-color super-resolution imaging by direct stochastic optical reconstruction microscopy (dSTORM) to investigate the nanoscale organization of mGluR4 at parallel fiber AZs in the mouse cerebellum. We find an inhomogeneous distribution, with multiple nanodomains inside AZs, each containing, on average, one to two mGluR4 subunits. Within these nanodomains, mGluR4s are often localized in close proximity to voltage-dependent CaV2.1 channels and Munc-18-1, which are both essential for neurotransmitter release. These findings provide previously unknown insights into the molecular organization of GPCRs at AZs, suggesting a likely implication of a close association between mGluR4 and the secretory machinery in modulating synaptic transmission.