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Mertins J, Finke J, Sies R, Rink KM, Hasenauer J, Lang T. The mesoscale organization of syntaxin 1A and SNAP25 is determined by SNARE-SNARE interactions. eLife 2021; 10:69236. [PMID: 34779769 PMCID: PMC8629428 DOI: 10.7554/elife.69236] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 11/14/2021] [Indexed: 01/01/2023] Open
Abstract
SNARE proteins have been described as the effectors of fusion events in the secretory pathway more than two decades ago. The strong interactions between SNARE domains are clearly important in membrane fusion, but it is unclear whether they are involved in any other cellular processes. Here, we analyzed two classical SNARE proteins, syntaxin 1A and SNAP25. Although they are supposed to be engaged in tight complexes, we surprisingly find them largely segregated in the plasma membrane. Syntaxin 1A only occupies a small fraction of the plasma membrane area. Yet, we find it is able to redistribute the far more abundant SNAP25 on the mesoscale by gathering crowds of SNAP25 molecules onto syntaxin clusters in a SNARE-domain-dependent manner. Our data suggest that SNARE domain interactions are not only involved in driving membrane fusion on the nanoscale, but also play an important role in controlling the general organization of proteins on the mesoscale. Further, we propose these mechanisms preserve active syntaxin 1A–SNAP25 complexes at the plasma membrane.
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Affiliation(s)
- Jasmin Mertins
- Departments of Membrane Biochemistry, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Jérôme Finke
- Departments of Membrane Biochemistry, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Ricarda Sies
- Departments of Membrane Biochemistry, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Kerstin M Rink
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Jan Hasenauer
- Computational Life Sciences, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany.,Interdisciplinary Research Unit Mathematics and Life Sciences, University of Bonn, Bonn, Germany.,Institute of Computational Biology, Helmholtz Center Munich - German Research Center for Environmental Health, Neuherberg, Germany
| | - Thorsten Lang
- Departments of Membrane Biochemistry, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
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2
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Padmanabhan P, Bademosi AT, Kasula R, Lauwers E, Verstreken P, Meunier FA. Need for speed: Super-resolving the dynamic nanoclustering of syntaxin-1 at exocytic fusion sites. Neuropharmacology 2019; 169:107554. [PMID: 30826343 DOI: 10.1016/j.neuropharm.2019.02.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 02/21/2019] [Accepted: 02/27/2019] [Indexed: 01/08/2023]
Abstract
Communication between cells relies on regulated exocytosis, a multi-step process that involves the docking, priming and fusion of vesicles with the plasma membrane, culminating in the release of neurotransmitters and hormones. Key proteins and lipids involved in exocytosis are subjected to Brownian movement and constantly switch between distinct motion states which are governed by short-lived molecular interactions. Critical biochemical reactions between exocytic proteins that occur in the confinement of nanodomains underpin the precise sequence of priming steps which leads to the fusion of vesicles. The advent of super-resolution microscopy techniques has provided the means to visualize individual molecules on the plasma membrane with high spatiotemporal resolution in live cells. These techniques are revealing a highly dynamic nature of the nanoscale organization of the exocytic machinery. In this review, we focus on soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) syntaxin-1, which mediates vesicular fusion. Syntaxin-1 is highly mobile at the plasma membrane, and its inherent speed allows fast assembly and disassembly of syntaxin-1 nanoclusters which are associated with exocytosis. We reflect on recent studies which have revealed the mechanisms regulating syntaxin-1 nanoclustering on the plasma membrane and draw inferences on the effect of synaptic activity, phosphoinositides, N-ethylmaleimide-sensitive factor (NSF), α-soluble NSF attachment protein (α-SNAP) and SNARE complex assembly on the dynamic nanoscale organization of syntaxin-1. This article is part of the special issue entitled 'Mobility and trafficking of neuronal membrane proteins'.
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Affiliation(s)
- Pranesh Padmanabhan
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Queensland, Australia
| | - Adekunle T Bademosi
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Queensland, Australia
| | - Ravikiran Kasula
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Queensland, Australia
| | - Elsa Lauwers
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Patrik Verstreken
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Frédéric A Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Queensland, Australia.
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3
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Makaraci P, Kim K. trans-Golgi network-bound cargo traffic. Eur J Cell Biol 2018; 97:137-149. [PMID: 29398202 DOI: 10.1016/j.ejcb.2018.01.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/15/2017] [Accepted: 01/16/2018] [Indexed: 12/19/2022] Open
Abstract
Cargo following the retrograde trafficking are sorted at endosomes to be targeted the trans-Golgi network (TGN), a central receiving organelle. Though molecular requirements and their interaction networks have been somewhat established, the complete understanding of the intricate nature of their action mechanisms in every step of the retrograde traffic pathway remains unachieved. This review focuses on elucidating known functions of key regulators, including scission factors at the endosome and tethering/fusion mediators at the receiving dock, TGN, as well as a diverse range of cargo.
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Affiliation(s)
- Pelin Makaraci
- Department of Biology, Missouri State University, 901 S National Ave., Springfield, MO 65807, USA
| | - Kyoungtae Kim
- Department of Biology, Missouri State University, 901 S National Ave., Springfield, MO 65807, USA.
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Merklinger E, Schloetel JG, Weber P, Batoulis H, Holz S, Karnowski N, Finke J, Lang T. The packing density of a supramolecular membrane protein cluster is controlled by cytoplasmic interactions. eLife 2017; 6. [PMID: 28722652 PMCID: PMC5536946 DOI: 10.7554/elife.20705] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 07/17/2017] [Indexed: 01/24/2023] Open
Abstract
Molecule clustering is an important mechanism underlying cellular self-organization. In the cell membrane, a variety of fundamentally different mechanisms drive membrane protein clustering into nanometre-sized assemblies. To date, it is unknown whether this clustering process can be dissected into steps differentially regulated by independent mechanisms. Using clustered syntaxin molecules as an example, we study the influence of a cytoplasmic protein domain on the clustering behaviour. Analysing protein mobility, cluster size and accessibility to myc-epitopes we show that forces acting on the transmembrane segment produce loose clusters, while cytoplasmic protein interactions mediate a tightly packed state. We conclude that the data identify a hierarchy in membrane protein clustering likely being a paradigm for many cellular self-organization processes. DOI:http://dx.doi.org/10.7554/eLife.20705.001
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Affiliation(s)
- Elisa Merklinger
- Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Jan-Gero Schloetel
- Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Pascal Weber
- Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Helena Batoulis
- Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Sarah Holz
- Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Nora Karnowski
- Chemical Biology, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Jérôme Finke
- Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Thorsten Lang
- Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
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5
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Weber P, Batoulis H, Rink KM, Dahlhoff S, Pinkwart K, Söllner TH, Lang T. Electrostatic anchoring precedes stable membrane attachment of SNAP25/SNAP23 to the plasma membrane. eLife 2017; 6. [PMID: 28240595 PMCID: PMC5362264 DOI: 10.7554/elife.19394] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 02/26/2017] [Indexed: 11/15/2022] Open
Abstract
The SNAREs SNAP25 and SNAP23 are proteins that are initially cytosolic after translation, but then become stably attached to the cell membrane through palmitoylation of cysteine residues. For palmitoylation to occur, membrane association is a prerequisite, but it is unclear which motif may increase the affinities of the proteins for the target membrane. In experiments with rat neuroendocrine cells, we find that a few basic amino acids in the cysteine-rich region of SNAP25 and SNAP23 are essential for plasma membrane targeting. Reconstitution of membrane-protein binding in a liposome assay shows that the mechanism involves protein electrostatics between basic amino acid residues and acidic lipids such as phosphoinositides that play a primary role in these interactions. Hence, we identify an electrostatic anchoring mechanism underlying initial plasma membrane contact by SNARE proteins, which subsequently become palmitoylated at the plasma membrane. DOI:http://dx.doi.org/10.7554/eLife.19394.001 Cells often communicate with each other by releasing chemicals that normally are stored in small membrane-bound compartments called vesicles. For example, when a neuron is stimulated, vesicles merge with its cell membrane and release their content into a gap between itself and other neurons. This complicated process involves many steps and molecules, including proteins called SNAREs. Some SNARE proteins reside at the inner side of the cell membrane and help vesicles to fuse with this membrane. Two SNARE proteins called SNAP25 and SNAP23 are produced in the liquid inside the cell and initially float freely. Eventually, these proteins become directly anchored to the cell membrane, however, not much is known about what happens to these proteins in between these stages, or how they first attach to the membrane before anchoring to it. Electrostatic forces between oppositely charged molecules are known to be important for them to bind with each other. Here, electrostatic forces are less likely to occur because SNAP25 and SNAP23 are both mostly negatively charged, and should therefore be repelled from the cell membrane, which also typically has a negative charge. However, both SNAP25 and SNAP23 have a small cluster of positively charged amino acids (the building blocks of proteins) near the attachment site, and Weber et al. have now tested whether this charge is sufficient to overcome the predicted repulsion. The approach involved making mutant proteins with either more or less positively charged attachment regions. Mutant SNAP25 or SNAP23 proteins with more positive charges may stick more tightly but not necessarily more permanently to the membrane. However, when the number of positive charges was lowered, more of the proteins remained floating freely in the liquid inside the cell. These results suggest that even a small number of positively charged amino acids is sufficient to help a protein bind to a cell membrane for further processing. The findings of Weber et al. reveal an early step in the life cycle of SNAP25 and SNAP23 before they anchor to the cell membrane. They suggest that finely tuned protein electrostatics can regulate how long a protein spends at a specific site and thereby indirectly determine its fate. Such fine-tuned protein electrostatics are difficult to recognize and could represent an underestimated regulatory mechanism in all types of cells. DOI:http://dx.doi.org/10.7554/eLife.19394.002
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Affiliation(s)
- Pascal Weber
- Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Helena Batoulis
- Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Kerstin M Rink
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Stefan Dahlhoff
- Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Kerstin Pinkwart
- Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Thomas H Söllner
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Thorsten Lang
- Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
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6
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Toft-Bertelsen TL, Ziomkiewicz I, Houy S, Pinheiro PS, Sørensen JB. Regulation of Ca2+ channels by SNAP-25 via recruitment of syntaxin-1 from plasma membrane clusters. Mol Biol Cell 2016; 27:3329-3341. [PMID: 27605709 PMCID: PMC5170865 DOI: 10.1091/mbc.e16-03-0184] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 09/01/2016] [Indexed: 12/20/2022] Open
Abstract
SNAP-25 regulates Ca2+ channels in an unknown manner. Endogenous and exogenous SNAP-25 inhibit Ca2+ currents indirectly by recruiting syntaxin-1 from clusters on the plasma membrane, thereby making it available for Ca2+ current inhibition. Thus the cell can regulate Ca2+ influx by expanding or contracting syntaxin-1 clusters. SNAP-25 regulates Ca2+ channels, with potentially important consequences for diseases involving an aberrant SNAP-25 expression level. How this regulation is executed mechanistically remains unknown. We investigated this question in mouse adrenal chromaffin cells and found that SNAP-25 inhibits Ca2+ currents, with the B-isoform being more potent than the A-isoform, but not when syntaxin-1 is cleaved by botulinum neurotoxin C. In contrast, syntaxin-1 inhibits Ca2+ currents independently of SNAP-25. Further experiments using immunostaining showed that endogenous or exogenous SNAP-25 expression recruits syntaxin-1 from clusters on the plasma membrane, thereby increasing the immunoavailability of syntaxin-1 and leading indirectly to Ca2+ current inhibition. Expression of Munc18-1, which recruits syntaxin-1 within the exocytotic pathway, does not modulate Ca2+ channels, whereas overexpression of the syntaxin-binding protein Doc2B or ubMunc13-2 increases syntaxin-1 immunoavailability and concomitantly down-regulates Ca2+ currents. Similar findings were obtained upon chemical cholesterol depletion, leading directly to syntaxin-1 cluster dispersal and Ca2+ current inhibition. We conclude that clustering of syntaxin-1 allows the cell to maintain a high syntaxin-1 expression level without compromising Ca2+ influx, and recruitment of syntaxin-1 from clusters by SNAP-25 expression makes it available for regulating Ca2+ channels. This mechanism potentially allows the cell to regulate Ca2+ influx by expanding or contracting syntaxin-1 clusters.
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Affiliation(s)
- Trine Lisberg Toft-Bertelsen
- Neurosecretion Group, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Iwona Ziomkiewicz
- Neurosecretion Group, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Sébastien Houy
- Neurosecretion Group, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Paulo S Pinheiro
- Neurosecretion Group, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Jakob B Sørensen
- Neurosecretion Group, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
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7
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Batoulis H, Schmidt TH, Weber P, Schloetel JG, Kandt C, Lang T. Concentration Dependent Ion-Protein Interaction Patterns Underlying Protein Oligomerization Behaviours. Sci Rep 2016; 6:24131. [PMID: 27052788 PMCID: PMC4823792 DOI: 10.1038/srep24131] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/21/2016] [Indexed: 11/09/2022] Open
Abstract
Salts and proteins comprise two of the basic molecular components of biological materials. Kosmotropic/chaotropic co-solvation and matching ion water affinities explain basic ionic effects on protein aggregation observed in simple solutions. However, it is unclear how these theories apply to proteins in complex biological environments and what the underlying ionic binding patterns are. Using the positive ion Ca2+ and the negatively charged membrane protein SNAP25, we studied ion effects on protein oligomerization in solution, in native membranes and in molecular dynamics (MD) simulations. We find that concentration-dependent ion-induced protein oligomerization is a fundamental chemico-physical principle applying not only to soluble but also to membrane-anchored proteins in their native environment. Oligomerization is driven by the interaction of Ca2+ ions with the carboxylate groups of aspartate and glutamate. From low up to middle concentrations, salt bridges between Ca2+ ions and two or more protein residues lead to increasingly larger oligomers, while at high concentrations oligomers disperse due to overcharging effects. The insights provide a conceptual framework at the interface of physics, chemistry and biology to explain binding of ions to charged protein surfaces on an atomistic scale, as occurring during protein solubilisation, aggregation and oligomerization both in simple solutions and membrane systems.
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Affiliation(s)
- Helena Batoulis
- Membrane Biochemistry, Life &Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Thomas H Schmidt
- Membrane Biochemistry, Life &Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Pascal Weber
- Membrane Biochemistry, Life &Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Jan-Gero Schloetel
- Membrane Biochemistry, Life &Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Christian Kandt
- Life Science Informatics B-IT, Computational Structural Biology, University of Bonn, Germany
| | - Thorsten Lang
- Membrane Biochemistry, Life &Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
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8
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Laporte G, Psaltis D. STED imaging of green fluorescent nanodiamonds containing nitrogen-vacancy-nitrogen centers. BIOMEDICAL OPTICS EXPRESS 2016; 7:34-44. [PMID: 26819815 PMCID: PMC4722908 DOI: 10.1364/boe.7.000034] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 11/19/2015] [Accepted: 11/30/2015] [Indexed: 05/21/2023]
Abstract
We report Stimulated Emission Depletion (STED) imaging of green fluorescent nanodiamonds containing Nitrogen-acancy-Nitrogen (NVN) centers with a resolution of 70 nm using a commercial microscope. Nanodiamonds have been demonstrated to have the potential to be excellent cellular biomarkers thanks to their low toxicity and nonbleaching fluorescence, and are especially appealing for superresolution imaging technique like STED microscopy. However, only red fluorescent nanodiamonds containing Nitrogen-Vacancy (NV) centers have been used with STED microscopy so far. The existence of only one color nonbleaching center limits the possible observations, for instance it complicates spatial correlation studies with STED. To provide a nonbleaching probe in a different color, we characterize here the optical properties of the NVN defect for STED imaging. We demonstrate STED imaging of the green fluorescent nanodiamonds containing NVN centers, opening the door for long term two-color STED observation. Furthermore we exemplify the use of green nanodiamonds as a second color nonbleaching STED biomarker by imaging 70 nm fluorescent crystals up taken into HeLa cells.
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Affiliation(s)
- Gregoire Laporte
- Laboratory of Optics, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Station 17, 1015 Lausanne, Switzerland
| | - Demetri Psaltis
- Laboratory of Optics, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Station 17, 1015 Lausanne, Switzerland
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9
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Destainville N, Schmidt TH, Lang T. Where Biology Meets Physics--A Converging View on Membrane Microdomain Dynamics. CURRENT TOPICS IN MEMBRANES 2015; 77:27-65. [PMID: 26781829 DOI: 10.1016/bs.ctm.2015.10.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
For several decades, the phenomenon of membrane component segregation into microdomains has been a well-known and highly debated subject, and varying concepts including the raft hypothesis, the fence-and-picket model, hydrophobic-mismatch, and specific protein-protein interactions have been offered as explanations. Here, we review the level of insight into the molecular architecture of membrane domains one is capable of obtaining through biological experimentation. Using SNARE proteins as a paradigm, comprehensive data suggest that several dozens of molecules crowd together into almost circular spots smaller than 100 nm. Such clusters are highly dynamical as they constantly capture and lose molecules. The organization has a strong influence on the functional availability of proteins and likely provides a molecular scaffold for more complex protein networks. Despite this high level of insight, fundamental open questions remain, applying not only to SNARE protein domains but more generally to all types of membrane domains. In this context, we explain the view of physical models and how they are beneficial in advancing our concept of micropatterning. While biological models generally remain qualitative and descriptive, physics aims towards making them quantitative and providing reproducible numbers, in order to discriminate between different mechanisms which have been proposed to account for experimental observations. Despite the fundamental differences in biological and physical approaches as far as cell membrane microdomains are concerned, we are able to show that convergence on common points of views is in reach.
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Affiliation(s)
- Nicolas Destainville
- Laboratoire de Physique Theorique (IRSAMC), Universite Toulouse 3-Paul Sabatier, UPS/CNRS, Toulouse, France
| | - Thomas H Schmidt
- Department of Membrane Biochemistry, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Thorsten Lang
- Department of Membrane Biochemistry, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
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10
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Kunieda K, Tsutsuki H, Ida T, Kishimoto Y, Kasamatsu S, Sawa T, Goshima N, Itakura M, Takahashi M, Akaike T, Ihara H. 8-Nitro-cGMP Enhances SNARE Complex Formation through S-Guanylation of Cys90 in SNAP25. ACS Chem Neurosci 2015. [PMID: 26221773 DOI: 10.1021/acschemneuro.5b00196] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nitrated guanine nucleotide 8-nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP) generated by reactive oxygen/nitrogen species causes protein S-guanylation. However, the mechanism of 8-nitro-cGMP formation and its protein targets in the normal brain have not been identified. Here, we investigated 8-nitro-cGMP generation and protein S-guanylation in the rodent brain. Immunohistochemistry indicated that 8-nitro-cGMP was produced by neurons, such as pyramidal cells and interneurons. Using liquid chromatography-tandem mass spectrometry, we determined endogenous 8-nitro-cGMP levels in the brain as 2.92 ± 0.10 pmol/mg protein. Based on S-guanylation proteomics, we identified several S-guanylated neuronal proteins, including SNAP25 which is a core member of the soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) complex. SNAP25 post-translational modification including palmitoylation, phosphorylation, and oxidation, are known to regulate neurotransmission. Our results demonstrate that S-guanylation of SNAP25 enhanced the stability of the SNARE complex, which was further promoted by Ca(2+)-dependent activation of neuronal nitric oxide synthase. Using site-directed mutagenesis, we identified SNAP25 cysteine 90 as the main target of S-guanylation which enhanced the stability of the SNARE complex. The present study revealed a novel target of redox signaling via protein S-guanylation in the nervous system and provided the first substantial evidence of 8-nitro-cGMP function in the nervous system.
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Affiliation(s)
- Kohei Kunieda
- Department
of Biological Science, Graduate School of Science, Osaka Prefecture University, Osaka 599-8531, Japan
| | - Hiroyasu Tsutsuki
- Department
of Microbiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Tomoaki Ida
- Department
of Environmental Health Sciences and Molecular Toxicology, Graduate
School of Medicine, Tohoku University, Miyagi 980-8575, Japan
| | - Yusuke Kishimoto
- Department
of Biological Science, Graduate School of Science, Osaka Prefecture University, Osaka 599-8531, Japan
| | - Shingo Kasamatsu
- Department
of Environmental Health Sciences and Molecular Toxicology, Graduate
School of Medicine, Tohoku University, Miyagi 980-8575, Japan
| | - Tomohiro Sawa
- Department
of Microbiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Naoki Goshima
- Quantitative
Proteomics Team, Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064, Japan
| | - Makoto Itakura
- Department
of Biochemistry, Kitasato University School of Medicine, Kanagawa 252-0374, Japan
| | - Masami Takahashi
- Department
of Biochemistry, Kitasato University School of Medicine, Kanagawa 252-0374, Japan
| | - Takaaki Akaike
- Department
of Environmental Health Sciences and Molecular Toxicology, Graduate
School of Medicine, Tohoku University, Miyagi 980-8575, Japan
| | - Hideshi Ihara
- Department
of Biological Science, Graduate School of Science, Osaka Prefecture University, Osaka 599-8531, Japan
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11
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Vreja IC, Kabatas S, Saka SK, Kröhnert K, Höschen C, Opazo F, Diederichsen U, Rizzoli SO. Secondary-ion mass spectrometry of genetically encoded targets. Angew Chem Int Ed Engl 2015; 54:5784-8. [PMID: 25783034 PMCID: PMC4471591 DOI: 10.1002/anie.201411692] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Indexed: 11/10/2022]
Abstract
Secondary ion mass spectrometry (SIMS) is generally used in imaging the isotopic composition of various materials. It is becoming increasingly popular in biology, especially for investigations of cellular metabolism. However, individual proteins are difficult to identify in SIMS, which limits the ability of this technology to study individual compartments or protein complexes. We present a method for specific protein isotopic and fluorescence labeling (SPILL), based on a novel click reaction with isotopic probes. Using this method, we added (19) F-enriched labels to different proteins, and visualized them by NanoSIMS and fluorescence microscopy. The (19) F signal allowed the precise visualization of the protein of interest, with minimal background, and enabled correlative studies of protein distribution and cellular metabolism or composition. SPILL can be applied to biological systems suitable for click chemistry, which include most cell-culture systems, as well as small model organisms.
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Affiliation(s)
- Ingrid C Vreja
- Department of Neuro- and Sensory Physiology, University Medical Center GöttingenHumboldtallee 23, 37073 Göttingen (Germany)
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen (Germany)
- International Max Planck Research School Molecular BiologyGöttingen (Germany)
| | - Selda Kabatas
- Institute for Organic and Biomolecular Chemistry, University of GöttingenTammannstrasse 2, 37077 Göttingen (Germany)
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen (Germany)
| | - Sinem K Saka
- Department of Neuro- and Sensory Physiology, University Medical Center GöttingenHumboldtallee 23, 37073 Göttingen (Germany)
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen (Germany)
| | - Katharina Kröhnert
- Department of Neuro- and Sensory Physiology, University Medical Center GöttingenHumboldtallee 23, 37073 Göttingen (Germany)
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen (Germany)
| | - Carmen Höschen
- Department of Ecology and Ecosystem Management, Center of Life and Food Sciences Weihenstephan, Technische Universität MünchenFreising-Weihenstephan (Germany)
| | - Felipe Opazo
- Department of Neuro- and Sensory Physiology, University Medical Center GöttingenHumboldtallee 23, 37073 Göttingen (Germany)
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen (Germany)
| | - Ulf Diederichsen
- Institute for Organic and Biomolecular Chemistry, University of GöttingenTammannstrasse 2, 37077 Göttingen (Germany)
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen (Germany)
| | - Silvio O Rizzoli
- Department of Neuro- and Sensory Physiology, University Medical Center GöttingenHumboldtallee 23, 37073 Göttingen (Germany)
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen (Germany)
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12
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Kiessling V, Liang B, Tamm LK. Reconstituting SNARE-mediated membrane fusion at the single liposome level. Methods Cell Biol 2015; 128:339-63. [PMID: 25997356 DOI: 10.1016/bs.mcb.2015.02.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Successful reconstitutions of SNARE-mediated intracellular membrane fusion have been achieved in bulk fusion assays since 1998 and in single liposome fusion assays since 2004. Especially in neuronal presynaptic SNARE-mediated exocytosis, fusion is controlled by numerous accessory proteins, of which some functions have also been reconstituted in vitro. The development of and results obtained with two fundamentally different single liposome fusion assays, namely liposome-to-supported membrane and liposome-to-liposome, are reviewed. Both assays distinguish between liposome docking and fusion steps of the overall fusion reaction and both assays are capable of resolving hemi-and full-fusion intermediates and end states. They have opened new windows for elucidating the mechanisms of these fundamentally important cellular reactions with unprecedented time and molecular resolution. Although many of the molecular actors in this process have been discovered, we have only scratched the surface of looking at their fascinating plays, interactions, and choreographies that lead to vesicle traffic as well as neurotransmitter and hormone release in the cell.
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Affiliation(s)
- Volker Kiessling
- Center for Membrane Biology and Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Binyong Liang
- Center for Membrane Biology and Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Lukas K Tamm
- Center for Membrane Biology and Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
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13
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Milovanovic D, Jahn R. Organization and dynamics of SNARE proteins in the presynaptic membrane. Front Physiol 2015; 6:89. [PMID: 25852575 PMCID: PMC4365744 DOI: 10.3389/fphys.2015.00089] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 03/05/2015] [Indexed: 01/19/2023] Open
Abstract
Our view of the lateral organization of lipids and proteins in the plasma membrane has evolved substantially in the last few decades. It is widely accepted that many, if not all, plasma membrane proteins and lipids are organized in specific domains. These domains vary widely in size, composition, and stability, and they represent platforms governing diverse cell functions. The presynaptic plasma membrane is a well-studied example of a membrane which undergoes rearrangements, especially during exo- and endocytosis. Many proteins and lipids involved in presynaptic function are known, and major efforts have been made to understand their spatial organization and dynamics. Here, we focus on the mechanisms underlying the organization of SNAREs, the key proteins of the fusion machinery, in distinct domains, and we discuss the functional significance of these clusters.
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Affiliation(s)
- Dragomir Milovanovic
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry Göttingen, Germany
| | - Reinhard Jahn
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry Göttingen, Germany
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14
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Vreja IC, Kabatas S, Saka SK, Kröhnert K, Höschen C, Opazo F, Diederichsen U, Rizzoli SO. Sekundärionen-Massenspektrometrie von genetisch kodierten Zielproteinen. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201411692] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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15
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Kavanagh DM, Smyth AM, Martin KJ, Dun A, Brown ER, Gordon S, Smillie KJ, Chamberlain LH, Wilson RS, Yang L, Lu W, Cousin MA, Rickman C, Duncan RR. A molecular toggle after exocytosis sequesters the presynaptic syntaxin1a molecules involved in prior vesicle fusion. Nat Commun 2014; 5:5774. [PMID: 25517944 PMCID: PMC4284649 DOI: 10.1038/ncomms6774] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 11/06/2014] [Indexed: 01/05/2023] Open
Abstract
Neuronal synapses are among the most scrutinized of cellular systems, serving as a model for all membrane trafficking studies. Despite this, synaptic biology has proven difficult to interrogate directly in situ due to the small size and dynamic nature of central synapses and the molecules within them. Here we determine the spatial and temporal interaction status of presynaptic proteins, imaging large cohorts of single molecules inside active synapses. Measuring rapid interaction dynamics during synaptic depolarization identified the small number of syntaxin1a and munc18-1 protein molecules required to support synaptic vesicle exocytosis. After vesicle fusion and subsequent SNARE complex disassembly, a prompt switch in syntaxin1a and munc18-1-binding mode, regulated by charge alteration on the syntaxin1a N-terminal, sequesters monomeric syntaxin1a from other disassembled fusion complex components, preventing ectopic SNARE complex formation, readying the synapse for subsequent rounds of neurotransmission.
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Affiliation(s)
- Deirdre M. Kavanagh
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh EH14 4AS, UK
- Edinburgh Super-Resolution Imaging Consortium, www.esric.org
| | - Annya M. Smyth
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh EH14 4AS, UK
- Edinburgh Super-Resolution Imaging Consortium, www.esric.org
- Centre for Integrative Physiology, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK
| | - Kirsty J. Martin
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh EH14 4AS, UK
- Edinburgh Super-Resolution Imaging Consortium, www.esric.org
| | - Alison Dun
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh EH14 4AS, UK
- Edinburgh Super-Resolution Imaging Consortium, www.esric.org
| | - Euan R. Brown
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh EH14 4AS, UK
- Edinburgh Super-Resolution Imaging Consortium, www.esric.org
| | - Sarah Gordon
- Centre for Integrative Physiology, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK
| | - Karen J. Smillie
- Centre for Integrative Physiology, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK
| | - Luke H. Chamberlain
- Strathclyde Institute of Pharmacy and Biomedical Sciences, 161 Cathedral Street, Glasgow G4 0RE, UK
| | - Rhodri S. Wilson
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh EH14 4AS, UK
- Edinburgh Super-Resolution Imaging Consortium, www.esric.org
| | - Lei Yang
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh EH14 4AS, UK
- Edinburgh Super-Resolution Imaging Consortium, www.esric.org
| | - Weiping Lu
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh EH14 4AS, UK
- Edinburgh Super-Resolution Imaging Consortium, www.esric.org
| | - Michael A. Cousin
- Centre for Integrative Physiology, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK
| | - Colin Rickman
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh EH14 4AS, UK
- Edinburgh Super-Resolution Imaging Consortium, www.esric.org
| | - Rory R. Duncan
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh EH14 4AS, UK
- Edinburgh Super-Resolution Imaging Consortium, www.esric.org
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16
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Tuson HH, Biteen JS. Unveiling the inner workings of live bacteria using super-resolution microscopy. Anal Chem 2014; 87:42-63. [PMID: 25380480 DOI: 10.1021/ac5041346] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Hannah H Tuson
- Department of Chemistry, University of Michigan , Ann Arbor, Michigan 48109, United States
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17
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Xie L, Liang T, Kang Y, Lin X, Sobbi R, Xie H, Chao C, Backx P, Feng ZP, Shyng SL, Gaisano HY. Phosphatidylinositol 4,5-biphosphate (PIP2) modulates syntaxin-1A binding to sulfonylurea receptor 2A to regulate cardiac ATP-sensitive potassium (KATP) channels. J Mol Cell Cardiol 2014; 75:100-10. [DOI: 10.1016/j.yjmcc.2014.07.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 07/15/2014] [Accepted: 07/18/2014] [Indexed: 11/15/2022]
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18
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Saka SK, Honigmann A, Eggeling C, Hell SW, Lang T, Rizzoli SO. Multi-protein assemblies underlie the mesoscale organization of the plasma membrane. Nat Commun 2014; 5:4509. [PMID: 25060237 PMCID: PMC4124874 DOI: 10.1038/ncomms5509] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 06/25/2014] [Indexed: 02/07/2023] Open
Abstract
Most proteins have uneven distributions in the plasma membrane. Broadly speaking, this may be caused by mechanisms specific to each protein, or may be a consequence of a general pattern that affects the distribution of all membrane proteins. The latter hypothesis has been difficult to test in the past. Here, we introduce several approaches based on click chemistry, through which we study the distribution of membrane proteins in living cells, as well as in membrane sheets. We found that the plasma membrane proteins form multi-protein assemblies that are long lived (minutes), and in which protein diffusion is restricted. The formation of the assemblies is dependent on cholesterol. They are separated and anchored by the actin cytoskeleton. Specific proteins are preferentially located in different regions of the assemblies, from their cores to their edges. We conclude that the assemblies constitute a basic mesoscale feature of the membrane, which affects the patterning of most membrane proteins, and possibly also their activity. Although many proteins adopt uneven distributions in the plasma membrane, it is not clear how these nanoscale heterogeneities relate to the general protein patterning of the membrane. Saka et al. use click chemistry to reveal the mesoscale organization of membrane proteins into multi-protein assemblies.
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Affiliation(s)
- Sinem K Saka
- 1] Department of Neuro- and Sensory Physiology, University of Göttingen Medical Centre, and Centre for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37075 Göttingen, Germany [2] International Max Planck Research School Molecular Biology, 37077 Göttingen, Germany
| | - Alf Honigmann
- Department of Nanobiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford OX3 9DS, UK
| | - Stefan W Hell
- Department of Nanobiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Thorsten Lang
- Department of Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, 53115 Bonn, Germany
| | - Silvio O Rizzoli
- Department of Neuro- and Sensory Physiology, University of Göttingen Medical Centre, and Centre for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37075 Göttingen, Germany
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19
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Kwiatek JM, Hinde E, Gaus K. Microscopy approaches to investigate protein dynamics and lipid organization. Mol Membr Biol 2014; 31:141-51. [DOI: 10.3109/09687688.2014.937469] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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20
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Bielopolski N, Lam AD, Bar-On D, Sauer M, Stuenkel EL, Ashery U. Differential interaction of tomosyn with syntaxin and SNAP25 depends on domains in the WD40 β-propeller core and determines its inhibitory activity. J Biol Chem 2014; 289:17087-99. [PMID: 24782308 DOI: 10.1074/jbc.m113.515296] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neuronal exocytosis depends on efficient formation of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes and is regulated by tomosyn, a SNARE-binding protein. To gain new information about tomosyn's activity, we characterized its mobility and organization on the plasma membrane (PM) in relation to other SNARE proteins and inhibition of exocytosis. By using direct stochastic optical reconstruction microscopy (dSTORM), we found tomosyn to be organized in small clusters adjacent to syntaxin clusters. In addition, we show that tomosyn is present in both syntaxin-tomosyn complexes and syntaxin-SNAP25-tomosyn complexes. Tomosyn mutants that lack residues 537-578 or 897-917 from its β-propeller core diffused faster on the PM and exhibited reduced binding to SNAP25, suggesting that these mutants shift the equilibrium between tomosyn-syntaxin-SNAP25 complexes on the PM to tomosyn-syntaxin complexes. As these deletion mutants impose less inhibition on exocytosis, we suggest that tomosyn inhibition is mediated via tomosyn-syntaxin-SNAP25 complexes and not tomosyn-syntaxin complexes. These findings characterize, for the first time, tomosyn's dynamics at the PM and its relation to its inhibition of exocytosis.
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Affiliation(s)
- Noa Bielopolski
- From the Department of Neurobiology, Life Sciences Faculty, and
| | - Alice D Lam
- the Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, and
| | - Dana Bar-On
- From the Department of Neurobiology, Life Sciences Faculty, and Sagol School of Neuroscience, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Markus Sauer
- the Department of Biotechnology and Biophysics, Julius Maximilians University Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Edward L Stuenkel
- the Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, and
| | - Uri Ashery
- From the Department of Neurobiology, Life Sciences Faculty, and Sagol School of Neuroscience, Tel Aviv University, 69978 Tel Aviv, Israel,
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21
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Abstract
Synaptic vesicle recycling is one of the best-studied cellular pathways. Many of the proteins involved are known, and their interactions are becoming increasingly clear. However, as for many other pathways, it is still difficult to understand synaptic vesicle recycling as a whole. While it is generally possible to point out how synaptic reactions take place, it is not always easy to understand what triggers or controls them. Also, it is often difficult to understand how the availability of the reaction partners is controlled: how the reaction partners manage to find each other in the right place, at the right time. I present here an overview of synaptic vesicle recycling, discussing the mechanisms that trigger different reactions, and those that ensure the availability of reaction partners. A central argument is that synaptic vesicles bind soluble cofactor proteins, with low affinity, and thus control their availability in the synapse, forming a buffer for cofactor proteins. The availability of cofactor proteins, in turn, regulates the different synaptic reactions. Similar mechanisms, in which one of the reaction partners buffers another, may apply to many other processes, from the biogenesis to the degradation of the synaptic vesicle.
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Affiliation(s)
- Silvio O Rizzoli
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen European Neuroscience Institute, Göttingen, Germany
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22
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James DJ, Martin TFJ. CAPS and Munc13: CATCHRs that SNARE Vesicles. Front Endocrinol (Lausanne) 2013; 4:187. [PMID: 24363652 PMCID: PMC3849599 DOI: 10.3389/fendo.2013.00187] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 11/18/2013] [Indexed: 11/13/2022] Open
Abstract
CAPS (Calcium-dependent Activator Protein for Secretion, aka CADPS) and Munc13 (Mammalian Unc-13) proteins function to prime vesicles for Ca(2+)-triggered exocytosis in neurons and neuroendocrine cells. CAPS and Munc13 proteins contain conserved C-terminal domains that promote the assembly of SNARE complexes for vesicle priming. Similarities of the C-terminal domains of CAPS/Munc13 proteins with Complex Associated with Tethering Containing Helical Rods domains in multi-subunit tethering complexes (MTCs) have been reported. MTCs coordinate multiple interactions for SNARE complex assembly at constitutive membrane fusion steps. We review aspects of these diverse tethering and priming factors to identify common operating principles.
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Affiliation(s)
- Declan J. James
- Department of Biochemistry, University of Wisconsin, Madison, WI, USA
| | - Thomas F. J. Martin
- Department of Biochemistry, University of Wisconsin, Madison, WI, USA
- *Correspondence: Thomas F. J. Martin, Department of Biochemistry, University of Wisconsin, 433 Babcock Drive, Madison, WI 53706, USA e-mail:
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23
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Abstract
Exocytosis, the process in which material is transported from the cell interior to the extracellular space, proceeds through a complex mechanism. Defects in this process are linked to a number of serious illnesses including diabetes, cancer, and a range of neuropathologies. In neuroendocrine cells, exocytosis involves the fusion of secretory vesicles, carrying signaling molecules, with the plasma membrane through the coordinated interplay of proteins, lipids, and small molecules. This process is highly regulated and occurs in a complex three-dimensional environment within the cell precisely coupled to the stimulus. The study of exocytosis poses significant challenges, involving rapidly changing, nano-scale, protein-protein, and protein-lipid interactions, at specialized sites in the cell. Over the last decade our understanding of neuroendocrine exocytosis has been greatly enhanced by developments in fluorescence microscopy. Modern microscopy encompasses a toolbox of advanced techniques, pushing the limits of sensitivity and resolution, to probe different properties of exocytosis. In more recent years, the development of super-resolution microscopy techniques, side-stepping the limits of optical resolution imposed by the physical properties of light, have started to provide an unparalleled view of exocytosis. In this review we will discuss how advances in fluorescence microscopy are shedding light on the spatial and temporal organization of the exocytotic machinery.
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Affiliation(s)
- Alicja Graczyk
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, UK
| | - Colin Rickman
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, UK
- *Correspondence: Colin Rickman, Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK e-mail:
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24
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25
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Kasai H, Takahashi N, Tokumaru H. Distinct Initial SNARE Configurations Underlying the Diversity of Exocytosis. Physiol Rev 2012; 92:1915-64. [DOI: 10.1152/physrev.00007.2012] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The dynamics of exocytosis are diverse and have been optimized for the functions of synapses and a wide variety of cell types. For example, the kinetics of exocytosis varies by more than five orders of magnitude between ultrafast exocytosis in synaptic vesicles and slow exocytosis in large dense-core vesicles. However, in all cases, exocytosis is mediated by the same fundamental mechanism, i.e., the assembly of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. It is often assumed that vesicles need to be docked at the plasma membrane and SNARE proteins must be preassembled before exocytosis is triggered. However, this model cannot account for the dynamics of exocytosis recently reported in synapses and other cells. For example, vesicles undergo exocytosis without prestimulus docking during tonic exocytosis of synaptic vesicles in the active zone. In addition, epithelial and hematopoietic cells utilize cAMP and kinases to trigger slow exocytosis of nondocked vesicles. In this review, we summarize the manner in which the diversity of exocytosis reflects the initial configurations of SNARE assembly, including trans-SNARE, binary-SNARE, unitary-SNARE, and cis-SNARE configurations. The initial SNARE configurations depend on the particular SNARE subtype (syntaxin, SNAP25, or VAMP), priming proteins (Munc18, Munc13, CAPS, complexin, or snapin), triggering proteins (synaptotagmins, Doc2, and various protein kinases), and the submembraneous cytomatrix, and they are the key to determining the kinetics of subsequent exocytosis. These distinct initial configurations will help us clarify the common SNARE assembly processes underlying exocytosis and membrane trafficking in eukaryotic cells.
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Affiliation(s)
- Haruo Kasai
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; and Faculty of Pharmaceutical Sciences at Kagawa, Tokushima Bunri University, Kagawa, Japan
| | - Noriko Takahashi
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; and Faculty of Pharmaceutical Sciences at Kagawa, Tokushima Bunri University, Kagawa, Japan
| | - Hiroshi Tokumaru
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; and Faculty of Pharmaceutical Sciences at Kagawa, Tokushima Bunri University, Kagawa, Japan
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26
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Mohrmann R, Sørensen JB. SNARE requirements en route to exocytosis: from many to few. J Mol Neurosci 2012; 48:387-94. [PMID: 22427188 DOI: 10.1007/s12031-012-9744-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Accepted: 02/29/2012] [Indexed: 12/30/2022]
Abstract
Although it has been known for almost two decades that the ternary complex of N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) constitutes the functional unit driving membrane fusion, our knowledge about the dynamical arrangement and organization of SNARE proteins and their complexes before and during vesicle exocytosis is still limited. Here, we review recent progress in this expanding field with emphasis on the question of fusion complex stoichiometry, i.e., how many SNARE proteins and complexes are needed for the fusion of a vesicle with the plasma membrane.
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Affiliation(s)
- Ralf Mohrmann
- Department of Physiology, University of Saarland, Homburg, Germany.
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27
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Saka S, Rizzoli SO. Super-resolution imaging prompts re-thinking of cell biology mechanisms: selected cases using stimulated emission depletion microscopy. Bioessays 2012; 34:386-95. [PMID: 22415724 DOI: 10.1002/bies.201100080] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The use of super-resolution imaging techniques in cell biology has yielded a wealth of information regarding cellular elements and processes that were invisible to conventional imaging. Focusing on images obtained by stimulated emission depletion (STED) microscopy, we discuss how the new high-resolution data influence the ways in which we use and interpret images in cell biology. Super-resolution images have lent support to some of our current hypotheses. But, more significantly, they have revealed unexpectedly complex processes that cannot be accounted for by the simpler models based on diffraction-limited imaging. The super-resolution imaging data challenge cell biologists to change their theoretical framework, by including, for instance, interpretations that describe multiple functions, functional errors or lack of function for cellular elements. In this context, we argue that descriptive research using super-resolution microscopy is now as necessary as hypothesis-driven research.
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Affiliation(s)
- Sinem Saka
- European Neuroscience Institute, DFG Center for Molecular Physiology of the Brain/Excellence Cluster, Göttingen, Germany
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28
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Müller T, Schumann C, Kraegeloh A. STED microscopy and its applications: new insights into cellular processes on the nanoscale. Chemphyschem 2012; 13:1986-2000. [PMID: 22374829 DOI: 10.1002/cphc.201100986] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Indexed: 11/09/2022]
Abstract
For about a decade, superresolution fluorescence microscopy has been advancing steadily, maturing from the proof-of-principle stage to routine application. Of the various techniques, STED (stimulated emission depletion) microscopy was the first to break the diffraction barrier. Today, it is a prominent and versatile form of superresolution light microscopy. STED microscopy has shed a sharper light on numerous topics in cell biology, but also in material sciences. Both disciplines extend into the nanometer range, making detailed studies of structural and functional relationships difficult or even impossible to achieve using diffraction-limited microscopy. With recent advancements like spectral multiplexing or live-cell imaging, STED microscopy makes nanoscale materials and components of the cell accessible for fluorescence-based investigations. With multicolor superresolution imaging, even the interactions between biological and engineered nanostructures can be studied in detail. This review gives an introduction into the working principle of STED microscopy, provides a detailed overview of recent advancements and new techniques implemented for use with STED microscopy and shows how these have been applied in the life sciences and nanotechnologies.
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Affiliation(s)
- Tobias Müller
- INM-Leibniz-Institute for New Materials, Nano Cell Interactions Group, Saarbrücken, Germany
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29
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Keighron JD, Ewing AG, Cans AS. Analytical tools to monitor exocytosis: a focus on new fluorescent probes and methods. Analyst 2012; 137:1755-63. [DOI: 10.1039/c2an15901e] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Ca2+ induces clustering of membrane proteins in the plasma membrane via electrostatic interactions. EMBO J 2011; 30:1209-20. [PMID: 21364530 DOI: 10.1038/emboj.2011.53] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 02/02/2011] [Indexed: 12/23/2022] Open
Abstract
Membrane proteins and membrane lipids are frequently organized in submicron-sized domains within cellular membranes. Factors thought to be responsible for domain formation include lipid-lipid interactions, lipid-protein interactions and protein-protein interactions. However, it is unclear whether the domain structure is regulated by other factors such as divalent cations. Here, we have examined in native plasma membranes and intact cells the role of the second messenger Ca(2+) in membrane protein organization. We find that Ca(2+) at low micromolar concentrations directly redistributes a structurally diverse array of membrane proteins via electrostatic effects. Redistribution results in a more clustered pattern, can be rapid and triggered by Ca(2+) influx through voltage-gated calcium channels and is reversible. In summary, the data demonstrate that the second messenger Ca(2+) strongly influences the organization of membrane proteins, thus adding a novel and unexpected factor that may control the domain structure of biological membranes.
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31
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Dun AR, Rickman C, Duncan RR. The t-SNARE complex: a close up. Cell Mol Neurobiol 2010; 30:1321-6. [PMID: 21046449 DOI: 10.1007/s10571-010-9599-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Accepted: 09/03/2010] [Indexed: 11/26/2022]
Abstract
The SNARE proteins, syntaxin, SNAP-25, and synaptobrevin have long been known to provide the driving force for vesicle fusion in the process of regulated exocytosis. Of particular interest is the initial interaction between SNAP-25 and syntaxin to form the t-SNARE heterodimer, an acceptor for subsequent synaptobrevin engagement. In vitro studies have revealed at least two different dynamic conformations of t-SNARE heterodimer defined by the degree of association of the C-terminal SNARE motif of SNAP-25 with syntaxin. At the plasma membrane, these proteins are organized into dense clusters of 50-60 nm in diameter. More recently, the t-SNARE interaction within these clusters was investigated in live cells at the molecular level, estimating each cluster to contain 35-70 t-SNARE molecules. This work reported the presence of both partially and fully zippered t-SNARE complex at the plasma membrane in agreement with the earlier in vitro findings. It also revealed a spatial segregation into distinct clusters containing predominantly one conformation apparently patterned by the surrounding lipid environment. The reason for this dynamic t-SNARE complex in exocytosis is uncertain; however, it does take us one step closer to understand the complex sequence of events leading to vesicle fusion, emphasizing the role of both membrane proteins and lipids.
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Affiliation(s)
- Alison R Dun
- Centre for Integrative Physiology, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
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Lang T, Rizzoli SO. Membrane protein clusters at nanoscale resolution: more than pretty pictures. Physiology (Bethesda) 2010; 25:116-24. [PMID: 20430955 DOI: 10.1152/physiol.00044.2009] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Fluorescence microscopy is powerful for analyzing the composition and dynamics of cellular elements, but studying precise molecule patterns is precluded due to diffraction limited resolution. This barrier has been lifted now through several superresolution microscopy techniques. They revealed that proteins assemble in defined groups (clusters). A new challenge thus appears for the biologist: to find out whether clusters are molecular machines, stabilizers of defined protein conformations, or simply protein reservoirs.
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Affiliation(s)
- Thorsten Lang
- LIMES-Institute, Laboratory of Membrane Biochemistry, University of Bonn, Bonn
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Walter AM, Wiederhold K, Bruns D, Fasshauer D, Sørensen JB. Synaptobrevin N-terminally bound to syntaxin-SNAP-25 defines the primed vesicle state in regulated exocytosis. ACTA ACUST UNITED AC 2010; 188:401-13. [PMID: 20142423 PMCID: PMC2819690 DOI: 10.1083/jcb.200907018] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Time-resolved measurements of exocytosis identify a domain of the SNARE complex required to keep vesicles readily releasable. Rapid neurotransmitter release depends on the ability to arrest the SNAP receptor (SNARE)–dependent exocytosis pathway at an intermediate “cocked” state, from which fusion can be triggered by Ca2+. It is not clear whether this state includes assembly of synaptobrevin (the vesicle membrane SNARE) to the syntaxin–SNAP-25 (target membrane SNAREs) acceptor complex or whether the reaction is arrested upstream of that step. In this study, by a combination of in vitro biophysical measurements and time-resolved exocytosis measurements in adrenal chromaffin cells, we find that mutations of the N-terminal interaction layers of the SNARE bundle inhibit assembly in vitro and vesicle priming in vivo without detectable changes in triggering speed or fusion pore properties. In contrast, mutations in the last C-terminal layer decrease triggering speed and fusion pore duration. Between the two domains, we identify a region exquisitely sensitive to mutation, possibly constituting a switch. Our data are consistent with a model in which the N terminus of the SNARE complex assembles during vesicle priming, followed by Ca2+-triggered C-terminal assembly and membrane fusion.
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Affiliation(s)
- Alexander M Walter
- Molecular Mechanism of Exocytosis, Department of Membrane Biophysics, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
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Rickman C, Medine CN, Dun AR, Moulton DJ, Mandula O, Halemani ND, Rizzoli SO, Chamberlain LH, Duncan RR. t-SNARE protein conformations patterned by the lipid microenvironment. J Biol Chem 2010; 285:13535-41. [PMID: 20093362 PMCID: PMC2859514 DOI: 10.1074/jbc.m109.091058] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The spatial distribution of the target (t-)SNARE proteins (syntaxin and SNAP-25) on the plasma membrane has been extensively characterized. However, the protein conformations and interactions of the two t-SNAREs in situ remain poorly defined. By using super-resolution optical techniques and fluorescence lifetime imaging microscopy, we observed that within the t-SNARE clusters syntaxin and SNAP-25 molecules interact, forming two distinct conformations of the t-SNARE binary intermediate. These are spatially segregated on the plasma membrane with each cluster exhibiting predominantly one of the two conformations, representing the two- and three-helical forms previously observed in vitro. We sought to explain why these two t-SNARE intermediate conformations exist in spatially distinct clusters on the plasma membrane. By disrupting plasma membrane lipid order, we found that all of the t-SNARE clusters now adopted a single conformational state corresponding to the three helical t-SNARE intermediates. Together, our results define spatially distinct t-SNARE intermediate states on the plasma membrane and how the conformation adopted can be patterned by the underlying lipid environment.
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Affiliation(s)
- Colin Rickman
- Centre for Integrative Physiology, School of Informatics, University of Edinburgh, Edinburgh EH8 9XD, Scotland, United Kingdom
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