Abstract
Cyclic adenosine monophosphate (cyclic AMP) is a second messenger, which is involved in the regulation of various cellular processes, including neuronal firing rate, synaptic plasticity, axon formation and axon elongation in brain. Although the main molecules in the cAMP-mediated signaling pathway are well studied, the spatio-temporal dynamics of the cAMP remain to be elucidated. Live imaging is an informative tool to investigate the cell signaling dynamics. It allows continuous monitoring of a specific cell over a period of time. Thus, optical probes for cAMP are important tools for studying the dynamics of cAMP signaling. Multiple genetically encoded cAMP probes are available [1], [2], including Förster resonance energy transfer (FRET) based or circular permutated fluorescent protein (cpFP) based probes. cpFP-based probes have an advantage of easier handling than FRET-based probes caused by monomeric detection and smaller molecular size. However, there is no cAMP probe compatible with violet light excitation. Therefore, we fused violet light excitable cpGFP to cyclic nucleotide binding domain (CBD) in E. coli cAMP receptor protein. This construct successfully responded to cAMP concentration changes. We show here the spectra data and live-cell imaging data of the violet light excitable cAMP probe which can be used for multi-signal fluorescence imaging.