Figure 2

Reciprocal labeling in an isogenic yeast cell line reveals extensive error and variation that is unidirectionally biased. (A) Histograms for SILAC ratios of two independent phosphoproteome experiments comparing isogenic wild-type S. cerevisiae as depicted in Fig. 1A. EVs are colored in orange. (B) Scatterplot comparing experimental data from the two SILAC experiments shown in (A). EVs are colored in orange. (C) Histogram showing unidirectional bias of error and variation toward quadrants 2 and 4 in plot from (B).