The decoy SNARE Tomosyn sets tonic versus phasic release properties and is required for homeostatic synaptic plasticity

eLife

Nicole A Aponte-Santiago¹  Karen L Cunningham¹  Chad W Sauvola²  Yulia Akbergenova²  J Troy Littleton³ 

[1] Department of Biology, Massachusetts Institute of Technology, Cambridge, United States;Department of Brain and Cognitive Sciences, The Picower Institute of Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States;Department of Brain and Cognitive Sciences, The Picower Institute of Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States;Department of Biology, Massachusetts Institute of Technology, Cambridge, United States;

关键词: synapse;    snare complex;    neurotransmitter release;    synaptic plasticity;    Drosophila;    synaptic vesicle;    D. melanogaster;   

DOI  :  10.7554/eLife.72841

来源: eLife Sciences Publications, Ltd

【 摘 要 】

Synaptic vesicle (SV) release probability (Pr) is a key presynaptic determinant of synaptic strength established by cell-intrinsic properties and further refined by plasticity. To characterize mechanisms that generate Pr heterogeneity between distinct neuronal populations, we examined glutamatergic tonic (Ib) and phasic (Is) motoneurons in Drosophila with stereotyped differences in Pr and synaptic plasticity. We found the decoy soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) Tomosyn is differentially expressed between these motoneuron subclasses and contributes to intrinsic differences in their synaptic output. Tomosyn expression enables tonic release in Ib motoneurons by reducing SNARE complex formation and suppressing Pr to generate decreased levels of SV fusion and enhanced resistance to synaptic fatigue. In contrast, phasic release dominates when Tomosyn expression is low, enabling high intrinsic Pr at Is terminals at the expense of sustained release and robust presynaptic potentiation. In addition, loss of Tomosyn disrupts the ability of tonic synapses to undergo presynaptic homeostatic potentiation.

【 授权许可】

CC BY