RIM-binding protein 2 regulates release probability by fine-tuning calcium channel localization at murine hippocampal synapses

M Katharina Grauel, Marta Maglione, Suneel Reddy-Alla, Claudia G Willmes, Marisa M Brockmann, Thorsten Trimbuch, Tanja Rosenmund, Maria Pangalos, Gülçin Vardar, Alexander Stumpf, Alexander M Walter, Benjamin R Rost, Britta J Eickholt, Volker Haucke, Dietmar Schmitz, Stephan J Sigrist, Christian Rosenmund

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Abstract

The tight spatial coupling of synaptic vesicles and voltage-gated Ca2+ channels (CaVs) ensures efficient action potential-triggered neurotransmitter release from presynaptic active zones (AZs). Rab-interacting molecule-binding proteins (RIM-BPs) interact with Ca2+ channels and via RIM with other components of the release machinery. Although human RIM-BPs have been implicated in autism spectrum disorders, little is known about the role of mammalian RIM-BPs in synaptic transmission. We investigated RIM-BP2-deficient murine hippocampal neurons in cultures and slices. Short-term facilitation is significantly enhanced in both model systems. Detailed analysis in culture revealed a reduction in initial release probability, which presumably underlies the increased short-term facilitation. Superresolution microscopy revealed an impairment in CaV2.1 clustering at AZs, which likely alters Ca2+ nanodomains at release sites and thereby affects release probability. Additional deletion of RIM-BP1 does not exacerbate the phenotype, indicating that RIM-BP2 is the dominating RIM-BP isoform at these synapses.

OriginalsprogEngelsk
TidsskriftProceedings of the National Academy of Sciences of the United States of America
Vol/bind113
Udgave nummer41
Sider (fra-til)11615-11620
Antal sider6
ISSN0027-8424
DOI
StatusUdgivet - 11 okt. 2016
Udgivet eksterntJa

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