In Situ Scanning Probe Microscopy Studies of Tetanus Toxin-Membrane Interactions

Slade, Andrea; Schoeniger, Joseph S.; Sasaki, Darryl Y.; Yip, Christopher M.

doi:10.1529/biophysj.105.080457

Cited by 21 publications

(16 citation statements)

References 66 publications

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“…Interestingly, however, the 50-kDa C-terminal region of the tetanus toxin heavy chain, which mediates the binding of the toxin to the ganglioside G T1b , has recently been shown by AFM analysis to cause the formation of 40-80 nm diameter and 1.5 nm deep indentations in supported lipid bilayers (48). These indentations developed slowly (i.e., over ~12 h) and were very stable.…”

Section: Discussionmentioning

confidence: 99%

Synaptotagmin Perturbs the Structure of Phospholipid Bilayers

et al. 2008

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Synaptotagmin I (syt), an integral protein of the synaptic vesicle membrane, is believed to act as a Ca 2+ sensor for neuronal exocytosis. Syt's cytoplasmic domain consists largely of two C2 domains, C2A and C2B. In response to Ca 2+ binding, the C2 domains interact with membranes, becoming partially embedded in the lipid bilayer. We have imaged syt C2AB in association with lipid bilayers under fluid, using AFM. As expected, binding of C2AB to bilayers required both an anionic phospholipid [phosphatidylserine (PS)] and Ca 2+ . C2AB associated with bilayers in the form of aggregates of varying stoichiometries, and aggregate size increased with an increase in PS content. Repeated scanning of bilayers revealed that as C2AB dissociated it left behind residual indentations in the bilayer. The mean depth of these identations was 1.81 nm, indicating that they did not span the bilayer. Individual C2 domains (C2A and C2B) also formed aggregates and produced bilayer indentations. Binding of C2AB to bilayers and the formation of indentations were significantly compromised by mutations that interfere with binding of Ca 2+ to syt or reduce the positive charge on the surface of C2B. We propose that bilayer perturbation by syt might be significant with respect to its ability to promote membrane fusion.Neurotransmitter release occurs in response to Ca 2+ influx across the presynaptic plasma membrane (1). There is persuasive evidence that a major Ca 2+ sensor at most nerve terminals is synaptotagmin I (syt), 1 an integral protein of the synaptic vesicle membrane (reviewed in refs 2 and 3). The cytoplasmic region of syt consists predominantly of two C2 domains, known as C2A and C2B, which bind three and two Ca 2+ ions, respectively (4, 5). In response to Ca 2+ binding, syt interacts both with negatively charged phospholipids, such as phosphatidylserine (PS) (5-11) and phosphatidylinositol 4,5-bisphosphate (PIP 2 ) (12-14), and with soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptors (SNAREs), proteins known to be key players in the process of membrane fusion (15-18). It is likely that the Ca 2+ -triggered binding of syt to both phospholipids and SNAREs is essential for its function as a Ca 2+ sensor for neurotransmitter release (19)(20)(21)(22)(23)(24).

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Section: Discussionmentioning

confidence: 99%

Synaptotagmin Perturbs the Structure of Phospholipid Bilayers

et al. 2008

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“…Different optical techniques have been combined with AFM. Among these techniques there are fluorescence microscopy (Frankel et al, 2006), confocal fluorescence microscopy (Shaw et al, 2006), (polarized) total internal reflection fluorescence microscopy (Slade et al, 2006;Oreopoulos and Yip, 2009), fluorescence correlation spectroscopy (Burns et al, 2005;Chiantia et al, 2006a) and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy (Verity et al, 2009).…”

Section: Chapter 3: Coupling Afm With Other Techniquesmentioning

confidence: 99%

Unraveling lipid/protein interaction in model lipid bilayers by Atomic Force Microscopy

Alessandrini

Facci

2011

J of Molecular Recognition

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The current view of the biological membrane is that in which lipids and proteins mutually interact to accomplish membrane functions. The lateral heterogeneity of the lipid bilayer can induce partitioning of membrane-associated proteins, favoring protein-protein interaction and influence signaling and trafficking. The Atomic Force Microscope allows to study the localization of membrane-associated proteins with respect to the lipid organization at the single molecule level and without the need for fluorescence staining. These features make AFM a technique of choice to study lipid/protein interactions in model systems or native membranes. Here we will review the technical aspects inherent to and the main results obtained by AFM in the study of protein partitioning in lipid domains concentrating in particular on GPI-anchored proteins, lipidated proteins, and transmembrane proteins. Whenever possible, we will also discuss the functional consequences of what has been imaged by Atomic Force Microscopy.

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“…(Alattia et al, 2007;Shaw et al, 2006cShaw et al, , 2008Shaw et al, , 2006dSlade et al, 2002Slade et al, , 2006. In these studies, the coupled imaging modalities offer a powerful means of addressing the key limitations of the individual techniques.…”

Section: Introductionmentioning

confidence: 99%