FRET-based evaluation of Bid cleavage in a single primary cultured neuron

► This is the first report to demonstrate FRET analysis in the cultured neuron, not the cell line. ► Significant signals were confined in the mitochondria because the FRET probe encodes Bid. ► A weak, but concentrated signal in the mitochondria enabled to demonstrate the change of FRET. ► Our report offers the new methodology to quantitate the FRET even in the cultured neuron.