scholarly journals Fluorescence Resonance Energy Transfer Detection of Synaptophysin I and Vesicle-associated Membrane Protein 2 Interactions during Exocytosis from Single Live Synapses

2002 ◽  
Vol 13 (8) ◽  
pp. 2706-2717 ◽  
Author(s):  
Maria Pennuto ◽  
David Dunlap ◽  
Andrea Contestabile ◽  
Fabio Benfenati ◽  
Flavia Valtorta

To investigate the molecular interactions of synaptophysin I and vesicle-associated membrane protein 2 (VAMP2)/synaptobrevin II during exocytosis, we have used time-lapse videomicroscopy to measure fluorescence resonance energy transfer in live neurons. For this purpose, fluorescent protein variants fused to synaptophysin I or VAMP2 were expressed in rat hippocampal neurons. We show that synaptophysin I and VAMP2 form both homo- and hetero-oligomers on the synaptic vesicle membrane. When exocytosis is stimulated with α-latrotoxin, VAMP2 dissociates from synaptophysin I even in the absence of appreciable exocytosis, whereas synaptophysin I oligomers disassemble only upon incorporation of the vesicle with the plasma membrane. We propose that synaptophysin I has multiple roles in neurotransmitter release, regulating VAMP2 availability for the solubleN-ethylmaleimide-sensitive factor attachment protein receptor complex and possibly participating in the late steps of exocytosis.

2004 ◽  
Vol 279 (50) ◽  
pp. 52399-52405 ◽  
Author(s):  
Anne J. Smith ◽  
Mark A. Sanders ◽  
Brian R. Thompson ◽  
Constantine Londos ◽  
Fredric B. Kraemer ◽  
...  

Previousin vitrostudies have established that hormone sensitive lipase (HSL) and adipocyte fatty acid-binding protein (AFABP) form a physical complex that presumably positions the FABP to accept a product fatty acid generated during catalysis. To assess AFABP-HSL interaction within a cellular context, we have used lipocytes derived from 293 cells (C8PA cells) and examined physical association using fluorescence resonance energy transfer. Transfection of C8PA cells with cyan fluorescent protein (CFP)-HSL, yellow fluorescent protein (YFP)-adipocyte FABP, or YFP-liver FABP revealed that under basal conditions each protein was cytoplasmic. In the presence of 20 μmforskolin, CFP-HSL translocated to the triacylglycerol droplet, coincident with BODIPY-FA labeled depots. Fluorescence resonance energy transfer analysis demonstrated that CFP-HSL associated with YFP-adipocyte FABP in both basal and forskolin-treated cells. In contrast, little if any fluorescence resonance energy transfer could be detected between CFP-HSL and YFP-liver FABP. These results suggest that a pre-lipolysis complex containing at least AFABP and HSL exists and that the complex translocates to the surface of the lipid droplet.


2020 ◽  
Vol 10 (10) ◽  
pp. 3508
Author(s):  
Haijun Yu ◽  
Haoxiang Li ◽  
Yao Zhou ◽  
Shengmin Zhou ◽  
Ping Wang

In this paper, a fluorescence resonance energy transfer (FRET)-based sensor for ultra-sensitive detection of H2O2 was developed by utilizing the unique enzymatic properties of peroxiredoxin (Prx) to H2O2. Cyan and yellow fluorescent protein (CFP and YFP) were fused to Prx and mutant thioredoxin (mTrx), respectively. In the presence of H2O2, Prx was oxidized into covalent homodimer through disulfide bonds, which were further reduced by mTrx to form a stable mixed disulfide bond intermediate between CFP-Prx and mTrx-YFP, inducing FRET. A linear quantification range of 10–320 nM was obtained according to the applied protein concentrations and the detection limit (LOD) was determined to be as low as 4 nM. By the assistance of glucose oxidase to transform glucose into H2O2, the CFP-Prx/mTrx-YFP system (CPmTY) was further exploited for the detection of glucose in real sample with good performance, suggesting this CPmTY protein sensor is highly practical.


Biochemistry ◽  
2001 ◽  
Vol 40 (8) ◽  
pp. 2502-2510 ◽  
Author(s):  
Hideaki Mizuno ◽  
Asako Sawano ◽  
Pharhad Eli ◽  
Hiroshi Hama ◽  
Atsushi Miyawaki

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