RIM-binding protein couples synaptic vesicle recruitment to release sites

J Cell Biol. 2020 Jul 6;219(7):e201902059. doi: 10.1083/jcb.201902059.

Abstract

At presynaptic active zones, arrays of large conserved scaffold proteins mediate fast and temporally precise release of synaptic vesicles (SVs). SV release sites could be identified by clusters of Munc13, which allow SVs to dock in defined nanoscale relation to Ca2+ channels. We here show in Drosophila that RIM-binding protein (RIM-BP) connects release sites physically and functionally to the ELKS family Bruchpilot (BRP)-based scaffold engaged in SV recruitment. The RIM-BP N-terminal domain, while dispensable for SV release site organization, was crucial for proper nanoscale patterning of the BRP scaffold and needed for SV recruitment of SVs under strong stimulation. Structural analysis further showed that the RIM-BP fibronectin domains form a "hinge" in the protein center, while the C-terminal SH3 domain tandem binds RIM, Munc13, and Ca2+ channels release machinery collectively. RIM-BPs' conserved domain architecture seemingly provides a relay to guide SVs from membrane far scaffolds into membrane close release sites.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Binding Sites
  • Calcium Channels / genetics
  • Calcium Channels / metabolism
  • Carrier Proteins / chemistry*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Central Nervous System / metabolism*
  • Central Nervous System / ultrastructure
  • Cloning, Molecular
  • Cytoskeletal Proteins / chemistry*
  • Cytoskeletal Proteins / genetics
  • Cytoskeletal Proteins / metabolism
  • Drosophila Proteins / chemistry*
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / metabolism*
  • Drosophila melanogaster / ultrastructure
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Female
  • Gene Expression Regulation
  • Genetic Vectors / chemistry
  • Genetic Vectors / metabolism
  • Larva / genetics
  • Larva / metabolism
  • Larva / ultrastructure
  • Male
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Nerve Tissue Proteins / chemistry
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Protein Binding
  • Protein Conformation, beta-Strand
  • Protein Interaction Domains and Motifs
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Synapses / metabolism*
  • Synapses / ultrastructure
  • Synaptic Transmission
  • Synaptic Vesicles / metabolism*
  • Synaptic Vesicles / ultrastructure
  • rab3 GTP-Binding Proteins / chemistry*
  • rab3 GTP-Binding Proteins / genetics
  • rab3 GTP-Binding Proteins / metabolism

Substances

  • BRP protein, Drosophila
  • Calcium Channels
  • Carrier Proteins
  • Cytoskeletal Proteins
  • Drosophila Proteins
  • Membrane Proteins
  • Nerve Tissue Proteins
  • RIM protein, Drosophila
  • Rbp protein, Drosophila
  • Recombinant Proteins
  • unc-13 protein, Drosophila
  • rab3 GTP-Binding Proteins