# Laser and single molecule microscopy (Kiessling)

> **NIH NIH P01** · UNIVERSITY OF VIRGINIA · 2020 · $108,736

## Abstract

PROJECT SUMMARY
The overall goal of this program project is to elucidate the precise molecular mechanism and regulation of the
fusion machine that drives exocytosis for the controlled release of neurotransmitter at nerve terminals. The
assembly of SNARE molecules residing in the synaptic vesicle and presynaptic plasma membrane takes
center stage and provides the driving energy for this process. Even though we know the structure of the fully
assembled cis-SNARE complex after fusion in atomic detail and have detailed conformational models for
several of the SNAREs before fusion, we do not precisely know how (i) they are conditioned with regulatory
proteins such as Munc18 and Munc13 to form an active acceptor complex on the plasma membrane, (ii) how
this acceptor SNARE complex engages with the synaptic vesicle SNARE upon encounter, and (iii) how this
high-energy trans-SNARE complex is ultimately triggered by the synaptic vesicle protein synaptotagmin and
calcium to proceed to full assembly and fusion.
Three projects led by three expert leaders in the biochemistry, structural biology, and biophysics of neuronal
exocytotic membrane fusion are designed to jointly unravel the precise molecular interactions that drive the
neuronal fusion machine through the vesicle docking, priming, and fusion steps with the highest possible
structural and time resolution. The team will seek to define the structures and configurations of the active
presynaptic acceptor SNARE complex and the fusion-restricted trans-SNARE complex between two
membranes, and the team will strive to uncover the molecular mechanism, by which calcium-synaptotagmin
engages with the membranes and/or complex to release their fusion-restriction.
To achieve this goal the team will use a unique combination of approaches ranging from highly innovative
biochemical procedures to reconstitute the relevant proteins, EPR, DEER, and NMR spectroscopy to
characterize the pertinent structures in membrane environments, and FLIC and single vesicle TIRF microscopy
to measure membrane topology and read out fusion on the millisecond timescale.

## Key facts

- **NIH application ID:** 9987652
- **Project number:** 5P01GM072694-14
- **Recipient organization:** UNIVERSITY OF VIRGINIA
- **Principal Investigator:** Volker Kiessling
- **Activity code:** P01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $108,736
- **Award type:** 5
- **Project period:** — → —

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9987652

## Citation

> US National Institutes of Health, RePORTER application 9987652, Laser and single molecule microscopy (Kiessling) (5P01GM072694-14). Retrieved via AI Analytics 2026-05-21 from https://api.ai-analytics.org/grant/nih/9987652. Licensed CC0.

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