Fluorescent biosensor for quantitative real-time measurements of inositol 1,4,5-trisphosphate in single living cells.
The second messenger inositol 1,4,5-trisphosphate (IP(3)) plays a central role in the generation of a variety of spatiotemporally complex intracellular Ca(2+) signals involved in the regulation of many essential physiological processes. Here we describe the development of "LIBRA", a novel ratiometric fluorescent IP(3) biosensor that allows for the quantitative monitoring of intracellular IP(3) concentrations in single living cells in real time. LIBRA consists of the IP(3)-binding domain of the rat type 3 IP(3) receptor fused between the fluorescence resonance energy transfer pair cyan fluorescent protein and yellow fluorescent protein and preceded by a membrane-targeting signal. We show that the LIBRA fluorescent signal is highly selective for IP(3) and unaffected by concentrations of Ca(2+) and ATP in the physiological range. In addition, LIBRA can be calibrated in situ. We demonstrate the utility of LIBRA by monitoring the temporal relationship between the responses intracellular IP(3) and Ca(2+) concentrations in SH-SY5Y cells following acetylcholine stimulation.
Department of Dental Pharmacology, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan. tanimura@hoku-iryo-u.ac.jp
Akihiko
A
Tanimura
Akihiro
A
Nezu
Takao
T
Morita
R James
RJ
Turner
Yosuke
Y
Tojyo
D000255:Adenosine Triphosphate / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D015374:Biosensing Techniques / Q000379:methods*; D002118:Calcium / Q000378:metabolism*; D002614:Chelating Agents / Q000494:pharmacology; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D049452:Green Fluorescent Proteins; D006863:Hydrogen-Ion Concentration; D015544:Inositol 1,4,5-Trisphosphate / Q000737:chemistry*; D015759:Ionomycin / Q000494:pharmacology; D008164:Luminescent Proteins / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D011950:Receptors, Cholinergic / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction; D013050:Spectrometry, Fluorescence; D013997:Time Factors; D014162:Transfection
D001426:Bacterial Proteins; D002614:Chelating Agents; D008164:Luminescent Proteins; D011950:Receptors, Cholinergic; D011976:Receptors, Muscarinic; D011993:Recombinant Fusion Proteins; C054562:yellow fluorescent protein, Bacteria; D049452:Green Fluorescent Proteins; D015759:Ionomycin; D015544:Inositol 1,4,5-Trisphosphate; D000255:Adenosine Triphosphate; D002118:Calcium