Figure 7. Protein interactions within the >100 kDa sample reveal a high density of protein-protein interactions.

Phosphoproteins and phosphoprotein complexes were obtained by passing yeast extract over the Pro-Q Diamond resin. The sample was then separated by size using a 100 kDa centrifugal concentrator. The retentate contained proteins and protein complexes larger than 100 kDa. Figure 8 shows the proteins found in the flow-through indicating a size smaller than 100 kDa. Osprey software was used to generate a figure depicting all possible interactions within the sample, where each node represents a single protein ⁵⁶. Proteins are represented by grey and black nodes where black nodes represent proteins previously reported to be phosphorylated (see Supplemental Table 2). Protein interactions from the entire retentate of the 100 kDa centrifugal concentrators were obtained from the BioGRID database ¹³ and are indicated by solid lines (http://www.thebiogrid.org/).