Forces, Kinetics, and Fusion Efficiency Altered by the Full-Length Synaptotagmin-1 -PI(4,5)P2 Interaction in Constrained Geometries.

A mechanism for full-length synaptotagmin-1 (syt-1) to interact with anionic bilayers and to promote fusion in the presence of SNAREs is proposed. Colloidal probe force spectroscopy in conjunction with tethered particle motion monitoring showed that in the absence of Ca2+ the binding of syt-1 to membranes depends on the presence and content of PI(4,5)P2. Addition of Ca2+ switches the interaction forces from weak to strong, eventually exceeding the cohesion of the C2A domain of syt-1 leading to partial unfolding of the protein. Fusion of single unilamellar vesicles equipped with syt-1 and synaptobrevin 2 with planar pore-spanning target membranes containing PS and PI(4,5)P2 shows an almost complete suppression of stalled intermediate fusion states and an accelerated fusion kinetics in the presence of Ca2+, which is further enhanced upon addition of ATP.

[1]  Qiu-Wen Wang,et al.  Synaptotagmin-1 interacts with PI(4,5)P2 to initiate synaptic vesicle docking in hippocampal neurons. , 2021, Cell reports.

[2]  C. Steinem,et al.  In vitro single vesicle fusion assays based on pore-spanning membranes: merits and drawbacks , 2020, European biophysics journal : EBJ.

[3]  J. Rothman,et al.  Synaptotagmin-1 membrane binding is driven by the C2B domain and assisted cooperatively by the C2A domain , 2020, Scientific Reports.

[4]  Sarah B. Nyenhuis,et al.  Conserved arginine residues in synaptotagmin 1 regulate fusion pore expansion through membrane contact , 2020, Nature Communications.

[5]  M. R. Bowers,et al.  Synaptotagmin: Mechanisms of an electrostatic switch , 2020, Neuroscience Letters.

[6]  C. Steinem,et al.  Fusion Pore Formation Observed During SNARE-Mediated Vesicle Fusion with Pore-Spanning Membranes , 2020, bioRxiv.

[7]  J. Rothman,et al.  Synaptotagmin 1 oligomers clamp and regulate different modes of neurotransmitter release , 2019, Proceedings of the National Academy of Sciences.

[8]  Sarah B. Nyenhuis,et al.  Phosphatidylinositol 4,5 bisphosphate controls the cis and trans interactions of synaptotagmin 1 , 2019, bioRxiv.

[9]  J. Rizo,et al.  Synaptotagmin-1 and Doc2b exhibit distinct membrane remodeling mechanisms , 2019, bioRxiv.

[10]  R. Jahn,et al.  SNARE-Mediated Fusion of Single Chromaffin Granules with Pore-Spanning Membranes. , 2019, Biophysical journal.

[11]  J. Rothman,et al.  Synaptotagmin oligomers are necessary and can be sufficient to form a Ca2+‐sensitive fusion clamp , 2019, FEBS letters.

[12]  C. Kalodimos,et al.  Atomic view of the energy landscape in the allosteric regulation of Abl kinase , 2017, Nature Structural & Molecular Biology.

[13]  Yongsoo Park,et al.  Models of synaptotagmin‐1 to trigger Ca2+‐dependent vesicle fusion , 2018, FEBS letters.

[14]  Christian Rosenmund,et al.  Synaptotagmin-1 drives synchronous Ca2+ triggered fusion by C2B domain-mediated synaptic vesicle-membrane attachment , 2017, Nature Neuroscience.

[15]  R. Jahn,et al.  Reconstitution of calcium-mediated exocytosis of dense-core vesicles , 2017, Science Advances.

[16]  U. Diederichsen,et al.  SNARE-Mediated Single-Vesicle Fusion Events with Supported and Freestanding Lipid Membranes. , 2017, Biophysical journal.

[17]  Christian Rosenmund,et al.  Should I stop or should I go? The role of complexin in neurotransmitter release , 2016, Nature Reviews Neuroscience.

[18]  Jong Bae Seo,et al.  Synaptotagmin-1 binds to PIP2-containing membrane but not to SNAREs at physiological ionic strength , 2015, Nature Structural &Molecular Biology.

[19]  Nicholas K. Sauter,et al.  Architecture of the Synaptotagmin-SNARE Machinery for Neuronal Exocytosis , 2015, Nature.

[20]  R. Jahn,et al.  Resolving single membrane fusion events on planar pore-spanning membranes , 2015, Scientific Reports.

[21]  S. Hell,et al.  Hydrophobic mismatch sorts SNARE proteins into distinct membrane domains , 2015, Nature Communications.

[22]  S. Hell,et al.  Phosphatidylinositol 4,5-bisphosphate clusters act as molecular beacons for vesicle recruitment , 2013, Nature Structural &Molecular Biology.

[23]  G. van den Bogaart,et al.  Controlling synaptotagmin activity by electrostatic screening , 2012, Nature Structural &Molecular Biology.

[24]  Hayder Amin,et al.  Membrane protein sequestering by ionic protein-lipid interactions , 2011, Nature.

[25]  J. Rothman,et al.  A conformational switch in complexin is required for synaptotagmin to trigger synaptic fusion , 2011, Nature Structural &Molecular Biology.

[26]  G. van den Bogaart,et al.  Counting the SNAREs needed for membrane fusion. , 2011, Journal of molecular cell biology.

[27]  H. Grubmüller,et al.  Synaptotagmin-1 may be a distance regulator acting upstream of SNARE nucleation , 2011, Nature Structural &Molecular Biology.

[28]  Antoine M. van Oijen,et al.  Analysis of kinetic intermediates in single-particle dwell-time distributions. , 2010, Biophysical journal.

[29]  Changbong Hyeon,et al.  Dynamic Ca2+-Dependent Stimulation of Vesicle Fusion by Membrane-Anchored Synaptotagmin 1 , 2010, Science.

[30]  Edwin R. Chapman,et al.  Synaptotagmin-Mediated Bending of the Target Membrane Is a Critical Step in Ca2+-Regulated Fusion , 2009, Cell.

[31]  A. Oberhauser,et al.  The c2 domains of human synaptotagmin 1 have distinct mechanical properties. , 2009, Biophysical journal.

[32]  E. Chapman,et al.  Synaptotagmin arrests the SNARE complex before triggering fast, efficient membrane fusion in response to Ca2+ , 2008, Nature Structural &Molecular Biology.

[33]  Alexander Stein,et al.  N- to C-Terminal SNARE Complex Assembly Promotes Rapid Membrane Fusion , 2006, Science.

[34]  T. Südhof,et al.  Close membrane-membrane proximity induced by Ca2+-dependent multivalent binding of synaptotagmin-1 to phospholipids , 2006, Nature Structural &Molecular Biology.

[35]  E. Chapman,et al.  PIP2 increases the speed of response of synaptotagmin and steers its membrane-penetration activity toward the plasma membrane , 2004, Nature Structural &Molecular Biology.

[36]  T. Südhof,et al.  Synaptotagmin I functions as a calcium regulator of release probability , 2001, Nature.

[37]  E. Kandel,et al.  Evidence for synaptotagmin as an inhibitory clamp on synaptic vesicle release in Aplysia neurons. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[38]  T. Südhof,et al.  Synaptotagmin I: A major Ca2+ sensor for transmitter release at a central synapse , 1994, Cell.