SFP6 fluorescent probes for imaging SAM dynamics in living cells

A genetically encoded probe, SFP6 (S-adenosyl-L-methionine fluorescent probe), based on the principle of fluorescence resonance energy transfer (FRET) was developed. The SFP6 probe dynamically visualizes changes in S-adenosyl-L-methionine (SAM) levels in living cells with high spatiotemporal resolution. The results demonstrated that SFP6 exhibits high sensitivity to SAM, can be stably expressed in various mammalian cells, and has excellent biocompatibility. The probe accurately monitors SAM levels and detects changes caused by both endogenous and exogenous factors. In summary, we have developed a fluorescent probe that can monitor changes in SAM levels with single-cell and time resolution. Dynamic changes in SAM levels are linked to various methylation modifications in cells. Therefore, monitoring intracellular SAM concentrations offers the possibility to study physiological and biochemical processes in real-time, such as gene expression and metabolism, related to methylation modifications.