Figure 2. Temporal course of the changes in KFERQ-PS-CFP2 fluorescence during starvation.
(a–c) Temporal changes in the green fluorescence pattern of photoactivated NIH3T3 cells stably expressing KFERQ-PS-CFP2 maintained in the presence (black circles) or absence (white squares) of serum for the indicated times. (a) Representative images of cells maintained in serum-free media. Quantification of the number of puncta/cell (b) and green fluorescence intensity (c). Values are expressed as percentage of fluorescence at time 0 and half-lives (t1/2) are indicated. Differences in the number of puncta and fluorescence intensity between cells maintained in the presence and absence of serum (*) were significant for p=0.048 (16h) and p=0.04 (24h) (t-test). (d) The same cells imaged in the cyan channel, before and at the indicated times after photoconversion (arrow) by exposure to 405nm light. Top: Representative images of the cyan fluorescence. Bottom: Quantification of the intensity of the cyan fluorescence. Values are expressed as times the intensity before photoconversion that was given an arbitrary value of 1. Values are mean + SE of 3 different experiments with >10 cells counted per experiment. Scale bars: 5μm