scholarly journals Live-cell multiphoton fluorescence correlation spectroscopy with an improved large Stokes shift fluorescent protein

2015 ◽  
Vol 26 (11) ◽  
pp. 2054-2066 ◽  
Author(s):  
Yinghua Guan ◽  
Matthias Meurer ◽  
Sarada Raghavan ◽  
Aleksander Rebane ◽  
Jake R. Lindquist ◽  
...  

We report an improved variant of mKeima, a monomeric long Stokes shift red fluorescent protein, hmKeima8.5. The increased intracellular brightness and large Stokes shift (∼180 nm) make it an excellent partner with teal fluorescent protein (mTFP1) for multiphoton, multicolor applications. Excitation of this pair by a single multiphoton excitation wavelength (MPE, 850 nm) yields well-separable emission peaks (∼120-nm separation). Using this pair, we measure homo- and hetero-oligomerization interactions in living cells via multiphoton excitation fluorescence correlation spectroscopy (MPE-FCS). Using tandem dimer proteins and small-molecule inducible dimerization domains, we demonstrate robust and quantitative detection of intracellular protein–protein interactions. We also use MPE-FCCS to detect drug–protein interactions in the intracellular environment using a Coumarin 343 (C343)-conjugated drug and hmKeima8.5 as a fluorescence pair. The mTFP1/hmKeima8.5 and C343/hmKeima8.5 combinations, together with our calibration constructs, provide a practical and broadly applicable toolbox for the investigation of molecular interactions in the cytoplasm of living cells.

2006 ◽  
Vol 91 (5) ◽  
pp. L45-L47 ◽  
Author(s):  
Peter Dedecker ◽  
Jun-ichi Hotta ◽  
Ryoko Ando ◽  
Atsushi Miyawaki ◽  
Yves Engelborghs ◽  
...  

2000 ◽  
Vol 113 (22) ◽  
pp. 3921-3930 ◽  
Author(s):  
R.H. Kohler ◽  
P. Schwille ◽  
W.W. Webb ◽  
M.R. Hanson

Dynamic tubular projections emanate from plastids in certain cells of vascular plants and are especially prevalent in non-photosynthetic cells. Tubules sometimes connect two or more different plastids and can extend over long distances within a cell, observations that suggest that the tubules may function in distribution of molecules within, to and from plastids. In a new application of two-photon excitation (2PE) fluorescence correlation spectroscopy (FCS), we separated diffusion of fluorescent molecules from active transport in vivo. We quantified the velocities of diffusion versus active transport of green fluorescent protein (GFP) within plastid tubules and in the cytosol in vivo. GFP moves by 3-dimensional (3-D) diffusion both in the cytosol and plastid tubules, but diffusion in tubules is about 50 times and 100 times slower than in the cytosol and an aqueous solution, respectively. Unexpectedly larger GFP units within plastid tubules exhibited active transport with a velocity of about 0.12 microm/second. Active transport might play an important role in the long-distance distribution of large numbers of molecules within the highly viscous stroma of plastid tubules.


2007 ◽  
Vol 82 (2) ◽  
pp. 156-162 ◽  
Author(s):  
Christophe Braet ◽  
Holger Stephan ◽  
Ian M. Dobbie ◽  
Denisio M. Togashi ◽  
Alan G. Ryder ◽  
...  

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