In vivo FRET Imaging

Nature has designed a variety of calcium binding proteins for specifically sensing calcium ions.  Taking advantage of the 3D structural knowledge of these proteins, one can rationally design novel recombinant proteins that are useful for biomedical research or other related fields.  We have developed calmodulin-peptide hybrids, which, in collaboration with Drs. R. Tsien and A. Miyawaki, led us to design novel fluorescent indicators for calcium named cameleons. Recently, we have succeeded in developimg a new version of cameleons based on our structural studies of the calmodulin-CaMKKp complex. Our laboratory is now eqipped with a state-of-the art fluorescence ratio imaging microscope for in vivo FRET work. We are committed to use this promising technology to visualize various biological processes in living cells (Truong & Ikura, 2001).

Truong, K., Sawano, A., Mizuno, H., Hama, H., Tong, K.I., Mal, T.K., Miyawaki, A., and Ikura, M. (2001) FRET-based in vivo Ca2+-imaging by a new calmodulin-GFP fusion molecule. Nature Structural Biology, in press.

Troung, K. and Ikura, M. (2001) FRET imaging microscopy to detect protein-protein interactions and protein conformational changes in vivo. Review article, Curr. Opn. Sturct. Biol., in press.

Miyawaki, A., Llopis, J., Heim, R., McCaffery, J.M., Adams, J.A., Ikura, M. and Tsien, R. (1997) Cameleons: Fluorescent Indicators for Ca2+ Based on Green Fluorescent Proteins and Calmodulin.  Nature 388, 882-887.

Martin, S.R., Bayley, P.M., Brown, S.E., Porumb, T., Zhang, M. and Ikura, M. (1996) Spectroscopic Characterization of a High Affinity Calmodulin-Target Peptide Hybrid Molecule. Biochemistry 35, 3508-3517.

Porumb, T., Harvey, T.S., Yau, P. and Ikura, M. (1994)  A Calmodulin-target Peptide Hybrid Protein with Unique Calcium Binding Properties.  Protein Engineering 7, 109-115.