A residue-level investigation of the equilibrium unfolding of the C2A domain of synaptotagmin 1

2009 ◽  
Vol 490 (2) ◽  
pp. 158-162 ◽  
Author(s):  
Veerappan Anbazhagan ◽  
Han-Min Wang ◽  
Ching-Song Lu ◽  
Chin Yu
Keyword(s):  
Residue Level ◽  
Synaptotagmin 1 ◽  
Equilibrium Unfolding ◽  
C2a Domain

scholarly journals Synaptotagmin 1 clamps synaptic vesicle fusion in mammalian neurons independent of complexin

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Nicholas A. Courtney ◽  
Huan Bao ◽  
Joseph S. Briguglio ◽  
Edwin R. Chapman
Keyword(s):  
Synaptic Vesicle ◽  
Vesicle Fusion ◽  
Snare Proteins ◽  
Major Focus ◽  
C2 Domains ◽  
Releasable Pool ◽  
Readily Releasable Pool ◽  
Synaptotagmin 1 ◽  
Synaptic Vesicle Fusion ◽  
C2a Domain

Abstract Synaptic vesicle (SV) exocytosis is mediated by SNARE proteins. Reconstituted SNAREs are constitutively active, so a major focus has been to identify fusion clamps that regulate their activity in synapses: the primary candidates are synaptotagmin (syt) 1 and complexin I/II. Syt1 is a Ca2+ sensor for SV release that binds Ca2+ via tandem C2-domains, C2A and C2B. Here, we first determined whether these C2-domains execute distinct functions. Remarkably, the C2B domain profoundly clamped all forms of SV fusion, despite synchronizing residual evoked release and rescuing the readily-releasable pool. Release was strongly enhanced by an adjacent C2A domain, and by the concurrent binding of complexin to trans-SNARE complexes. Knockdown of complexin had no impact on C2B-mediated clamping of fusion. We postulate that the C2B domain of syt1, independent of complexin, is the molecular clamp that arrests SVs prior to Ca2+-triggered fusion.

scholarly journals Structure/Function Analysis of Ca2+Binding to the C2A Domain of Synaptotagmin 1

2002 ◽  
Vol 22 (19) ◽  
pp. 8438-8446 ◽  
Author(s):  
Rafael Fernández-Chacón ◽  
Ok-Ho Shin ◽  
Andreas Königstorfer ◽  
Maria F. Matos ◽  
Alexander C. Meyer ◽  
...  
Keyword(s):  
Structure Function ◽  
Function Analysis ◽  
Synaptotagmin 1 ◽  
C2a Domain

Equilibrium unfolding of DLC8 monomer by urea and guanidine hydrochloride: Distinctive global and residue level features

Biochimie ◽  
2007 ◽  
Vol 89 (1) ◽  
pp. 117-134 ◽  
Author(s):  
Amarnath Chatterjee ◽  
P.M. Krishna Mohan ◽  
Arati Prabhu ◽  
Anindya Ghosh-Roy ◽  
Ramakrishna V. Hosur
Keyword(s):  
Guanidine Hydrochloride ◽  
Residue Level ◽  
Equilibrium Unfolding

scholarly journals Synaptotagmin-1 membrane binding is driven by the C2B domain and assisted cooperatively by the C2A domain

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Clémence Gruget ◽  
Oscar Bello ◽  
Jeff Coleman ◽  
Shyam S. Krishnakumar ◽  
Eric Perez ◽  
...  
Keyword(s):  
Neurotransmitter Release ◽  
Mutational Analysis ◽  
Membrane Binding ◽  
Surface Force ◽  
Membrane Interaction ◽  
C2 Domains ◽  
Binding Energetics ◽  
Synaptotagmin 1 ◽  
Site Binding ◽  
C2a Domain

Abstract Synaptotagmin interaction with anionic lipid (phosphatidylserine/phosphatidylinositol) containing membranes, both in the absence and presence of calcium ions (Ca2+), is critical to its central role in orchestrating neurotransmitter release. The molecular surfaces involved, namely the conserved polylysine motif in the C2B domain and Ca2+-binding aliphatic loops on both C2A and C2B domains, are known. Here we use surface force apparatus combined with systematic mutational analysis of the functional surfaces to directly measure Syt1-membrane interaction and fully map the site-binding energetics of Syt1 both in the absence and presence of Ca2+. By correlating energetics data with the molecular rearrangements measured during confinement, we find that both C2 domains cooperate in membrane binding, with the C2B domain functioning as the main energetic driver, and the C2A domain acting as a facilitator.

scholarly journals A Polybasic Patch on Synaptotagmin-1 C2A Domain is Essential for Evoked Release and Dilation of Fusion Pores

2020 ◽  
Vol 118 (3) ◽  
pp. 400a
Author(s):  
Zhenyong Wu ◽  
Lu Ma ◽  
Jie Zhu ◽  
Nicholas Courtney ◽  
Yongli Zhang ◽  
...  
Keyword(s):  
Synaptotagmin 1 ◽  
Fusion Pores ◽  
C2a Domain

scholarly journals The role of the C2A domain of synaptotagmin 1 in asynchronous neurotransmitter release

PLoS ONE ◽  
2020 ◽  
Vol 15 (5) ◽  
pp. e0232991
Author(s):  
Mallory C. Shields ◽  
Matthew R. Bowers ◽  
Hannah L. Kramer ◽  
McKenzie M. Fulcer ◽  
Lara C. Perinet ◽  
...  
Keyword(s):  
Neurotransmitter Release ◽  
Synaptotagmin 1 ◽  
C2a Domain

Characterization of DLC1-SAM Equilibrium Unfolding at the Amino Acid Residue Level

Biochemistry ◽  
2009 ◽  
Vol 48 (19) ◽  
pp. 4040-4049 ◽  
Author(s):  
Shuai Yang ◽  
Christian G. Noble ◽  
Daiwen Yang
Keyword(s):  
Amino Acid ◽  
Amino Acid Residue ◽  
Residue Level ◽  
Equilibrium Unfolding

scholarly journals Mutations that disrupt Ca2+-binding activity endow Doc2β with novel functional properties during synaptic transmission

2014 ◽  
Vol 25 (4) ◽  
pp. 481-494 ◽  
Author(s):  
Jon D. Gaffaney ◽  
Renhao Xue ◽  
Edwin R. Chapman
Keyword(s):  
Plasma Membrane ◽  
Synaptic Transmission ◽  
Functional Properties ◽  
Binding Activity ◽  
Mutant Form ◽  
C2 Domains ◽  
Synaptotagmin 1 ◽  
Asynchronous Release ◽  
Vesicle Pool ◽  
C2a Domain

Double C2-domain protein (Doc2) is a Ca2+-binding protein implicated in asynchronous and spontaneous neurotransmitter release. Here we demonstrate that each of its C2 domains senses Ca2+; moreover, the tethered tandem C2 domains display properties distinct from the isolated domains. We confirm that overexpression of a mutant form of Doc2β, in which two acidic Ca2+ ligands in the C2A domain and two in the C2B domain have been neutralized, results in markedly enhanced asynchronous release in synaptotagmin 1–knockout neurons. Unlike wild-type (wt) Doc2β, which translocates to the plasma membrane in response to increases in [Ca2+]i, the quadruple Ca2+-ligand mutant does not bind Ca2+ but is constitutively associated with the plasma membrane; this effect is due to substitution of Ca2+ ligands in the C2A domain. When overexpressed in wt neurons, Doc2β affects only asynchronous release; in contrast, Doc2β Ca2+-ligand mutants that constitutively localize to the plasma membrane enhance both the fast and slow components of synaptic transmission by increasing the readily releasable vesicle pool size; these mutants also increase the frequency of spontaneous release events. Thus, mutations in the C2A domain of Doc2β that were intended to disrupt Ca2+ binding result in an anomalous enhancement of constitutive membrane-binding activity and endow Doc2β with novel functional properties.

scholarly journals Cooperativity and Avidity in Membrane Binding by C2AB Tandem Domains of Synaptotagmins 1 and 7

2018 ◽  
Author(s):  
H. Tran ◽  
L. Anderson ◽  
J. Knight
Keyword(s):  
Hormone Secretion ◽  
Membrane Binding ◽  
Dissociation Rate ◽  
Dissociation Kinetics ◽  
Kinetic Measurements ◽  
C2 Domains ◽  
Synaptotagmin 1 ◽  
Fusion Pores ◽  
Fluorescence Kinetic ◽  
C2a Domain

AbstractSynaptotagmin-1 (Syt-1) and synaptotagmin-7 (Syt-7) contain analogous tandem C2 domains, C2A and C2B, which together serve as a Ca2+ sensor to bind membranes and promote the stabilization of exocytotic fusion pores. Functionally, Syt-1 triggers fast release of neurotransmitters, while Syt-7 is involved in lower-Ca2+ processes such as hormone secretion. Evidence suggests that Syt-1 C2 domains bind membranes cooperatively, penetrating farther into membranes as the C2AB tandem than as individual C2 domains. In contrast, we previously reported that the two C2 domains of Syt-7 bind membranes independently, based in part on measurements of their liposome dissociation kinetics. Here, we have investigated the effects of C2A-C2B interdomain cooperativity with Syt-1 and Syt-7 using directly comparable measurements. We report Ca2+ sensitivities, dissociation kinetics, and membrane insertion using liposomes approximating physiological lipid compositions. Equilibrium Ca2+ titrations confirm that the Syt-7 C2AB tandem has a greater Ca2+ sensitivity of membrane binding than either of its individual domains. Stopped-flow fluorescence kinetic measurements show that Syt-1 C2AB dissociates from liposome membranes much more slowly than either of its isolated C2 domains, suggesting that the two C2 domains of Syt-1 bind membranes cooperatively. In contrast, the dominant population of Syt-7 C2AB has a dissociation rate comparable to its C2A domain, indicating a lack of cooperativity, while only a small subpopulation dissociates at a slower rate. Measurements using an environment-sensitive fluorescent probe indicate that the Syt-7 C2B domain inserts more deeply into membranes as part of the C2AB tandem, similarly to Syt-1. Overall, these measurements are consistent with a model in which the structural linkage of C2A and C2B impacts the membrane-binding geometry of synaptotagmin C2B domains, but imparts little or no cooperativity to Syt-7 membrane binding and dissociation events that are dominated by its C2A domain.

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