scholarly journals Real-time observation of flow-induced cytoskeletal stress in living cells

2011 ◽  
Vol 301 (3) ◽  
pp. C646-C652 ◽  
Author(s):  
Jason Rahimzadeh ◽  
Fanjie Meng ◽  
Fredrick Sachs ◽  
Jianbin Wang ◽  
Deepika Verma ◽  
...  
Keyword(s):  
Shear Stress ◽  
Mechanical Stress ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Living Cells ◽  
Host Protein ◽  
Apical Surface ◽  
Intracellular Ca ◽  
In Series ◽  
Time Observation

The mechanical stress due to shear flow has profound effects on cell proliferation, transport, gene expression, and apoptosis. The mechanisms for flow sensing and transduction are unclear, but it is postulated that fluid flow pulls upon the apical surface, and the resulting stress is eventually transmitted through the cytoskeleton to adhesion plaques on the basal surface. Here we report a direct observation of this flow-induced stress in the cytoskeleton in living cells using a parallel plate microfluidic chip with a fluorescence resonance energy transfer (FRET)-based mechanical stress sensor in actinin. The sensing cassette was genetically inserted into the cytoskeletal host protein and transfected into Madin-Darby canine kidney cells. A shear stress of 10 dyn/cm2 resulted in a rapid increase in the FRET ratio indicating a decrease in stress across actinin with flow. The effect was reversible, and cells were able to respond to repeated stimulation and showed adaptive changes in the cytoskeleton. Flow-induced Ca2+ elevation did not affect the response, suggesting that flow-induced changes in actinin stress are insensitive to intracellular Ca2+ level. The reduction in FRET ratio suggests actin filaments are under normal compression in the presence of flow shear stress due to changes in cell shape, and/or actinin is not in series with actin. Treatment with cytochalasin-D that disrupts F-actin reduced prestress and the response to flow. The FRET/flow method is capable of resolving changes of stress in multiple proteins with optical spatial resolution and time resolution >1 Hz. This promises to provide insight into the force distribution and transduction in all cells.

scholarly journals A Fluorescence Resonance Energy Transfer-Based Analytical Tool for Nitrate Quantification in Living Cells

ACS Omega ◽  
2020 ◽  
Vol 5 (46) ◽  
pp. 30306-30314
Author(s):  
Urooj Fatima ◽  
Fuad Ameen ◽  
Neha Soleja ◽  
Parvez Khan ◽  
Abobakr Almansob ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Fluorescence Resonance Energy Transfer ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Living Cells ◽  
Analytical Tool ◽  
Fluorescence Resonance

scholarly journals Distribution of a Glycosylphosphatidylinositol-anchored Protein at the Apical Surface of MDCK Cells Examined at a Resolution of <100 Å Using Imaging Fluorescence Resonance Energy Transfer

1998 ◽  
Vol 142 (1) ◽  
pp. 69-84 ◽  
Author(s):  
A.K. Kenworthy ◽  
M. Edidin
Keyword(s):  
Energy Transfer ◽  
Lipid Rafts ◽  
Fluorescence Resonance Energy Transfer ◽  
Mdck Cells ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Membrane Microdomains ◽  
Apical Surface ◽  
Donor And Acceptor ◽  
Fluorescence Resonance

Membrane microdomains (“lipid rafts”) enriched in glycosylphosphatidylinositol (GPI)-anchored proteins, glycosphingolipids, and cholesterol have been implicated in events ranging from membrane trafficking to signal transduction. Although there is biochemical evidence for such membrane microdomains, they have not been visualized by light or electron microscopy. To probe for microdomains enriched in GPI- anchored proteins in intact cell membranes, we used a novel form of digital microscopy, imaging fluorescence resonance energy transfer (FRET), which extends the resolution of fluorescence microscopy to the molecular level (&lt;100 Å). We detected significant energy transfer between donor- and acceptor-labeled antibodies against the GPI-anchored protein 5′ nucleotidase (5′ NT) at the apical membrane of MDCK cells. The efficiency of energy transfer correlated strongly with the surface density of the acceptor-labeled antibody. The FRET data conformed to theoretical predictions for two-dimensional FRET between randomly distributed molecules and were inconsistent with a model in which 5′ NT is constitutively clustered. Though we cannot completely exclude the possibility that some 5′ NT is in clusters, the data imply that most 5′ NT molecules are randomly distributed across the apical surface of MDCK cells. These findings constrain current models for lipid rafts and the membrane organization of GPI-anchored proteins.

scholarly journals Visualization of growth signal transduction cascades in living cells with genetically encoded probes based on Förster resonance energy transfer

2008 ◽  
Vol 363 (1500) ◽  
pp. 2143-2151 ◽  
Author(s):  
Kazuhiro Aoki ◽  
Etsuko Kiyokawa ◽  
Takeshi Nakamura ◽  
Michiyuki Matsuda
Keyword(s):  
Signal Transduction ◽  
Energy Transfer ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Living Cells ◽  
Small Gtpases ◽  
Forster Resonance Energy Transfer ◽  
Fluorescence Probes ◽  
Förster Resonance Energy Transfer ◽  
Förster Resonance

Fluorescence probes based on the principle of Förster resonance energy transfer (FRET) have shed new light on our understanding of signal transduction cascades. Among them, unimolecular FRET probes containing fluorescence proteins are rapidly increasing in number because these genetically encoded probes can be easily loaded into living cells and allow simple acquisition of FRET images. We have developed probes for small GTPases, tyrosine kinases, serine–threonine kinases and phosphoinositides. Images obtained with these probes have revealed that membrane protrusions such as nascent lamellipodia or neurites provide an active signalling platform in the growth factor-stimulated cells.

scholarly journals Developing fluorescence sensor probe to capture activated muscle-specific calpain-3 (CAPN3) in living muscle cells

Biology Open ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. bio048975
Author(s):  
Koichi Ojima ◽  
Shoji Hata ◽  
Fumiko Shinkai-Ouchi ◽  
Mika Oe ◽  
Susumu Muroya ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Protease Activity ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Living Cells ◽  
Spectral Studies ◽  
Partial Amino Acid Sequence ◽  
Promising Tool ◽  
Calpain 3 ◽  
Sensor Probe

ABSTRACTCalpain-3 (CAPN3) is a muscle-specific type of calpain whose protease activity is triggered by Ca2+. Here, we developed CAPN3 sensor probes (SPs) to detect activated-CAPN3 using a fluorescence/Förster resonance energy transfer (FRET) technique. In our SPs, partial amino acid sequence of calpastatin, endogenous CAPN inhibitor but CAPN3 substrate, is inserted between two different fluorescence proteins that cause FRET. Biochemical and spectral studies revealed that CAPN3 cleaved SPs and changed emission wavelengths of SPs. Importantly, SPs were scarcely cleaved by CAPN1 and CAPN2. Furthermore, our SP successfully captured the activation of endogenous CAPN3 in living myotubes treated with ouabain. Our SPs would become a promising tool to detect the dynamics of CAPN3 protease activity in living cells.

scholarly journals FRET Microscopy in Yeast

Biosensors ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 122 ◽  
Author(s):  
Skruzny ◽  
Pohl ◽  
Abella
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fluorescent Proteins ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Living Cells ◽  
Bioactive Molecules ◽  
Biophysical Processes ◽  
Microscopy Method ◽  
Fret Biosensors

Förster resonance energy transfer (FRET) microscopy is a powerful fluorescence microscopy method to study the nanoscale organization of multiprotein assemblies in vivo. Moreover, many biochemical and biophysical processes can be followed by employing sophisticated FRET biosensors directly in living cells. Here, we summarize existing FRET experiments and biosensors applied in yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, two important models of fundamental biomedical research and efficient platforms for analyses of bioactive molecules. We aim to provide a practical guide on suitable FRET techniques, fluorescent proteins, and experimental setups available for successful FRET experiments in yeasts.

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