Dynamic activation of Src induced by low-power laser irradiation in living cells mediated by reactive oxygen species

Src tyrosine tdnases are central components of adhesive and growth factor responses and play key roles in the control of cell proliferation, survival and adhesion. In present study, to monitor Src activity in living cells in real time, we transfected Hela cells with Src reporter constructed on the basis of fluorescence resonance energy transfer (FRET) technique. We reported that 15J/cm(2) low-power laser irradiation (LPLI), as well as the addition of EGF to serum-starved Hela cells, activates tyrosine kinase Src. Reactive oxygen species (ROS) as intracellular messengers, were reported to play important roles in LPLI and EGF triggered signaling pathway. Using fluorescent probes 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA), we found LPLI and EGF stimulation caused ROS increase to 40% and 100% above the basal level. Exogenons added H2O2 (200 similar to 250 mu M) can also markly activate Src. We suggest that LPLI activates Src by inducing ROS production.