Fig. 3.

Bioinformatics analysis of the identified in vitro substrates of ROP18. A, integration of known PPI relationships revealed that 32 of the 68 identified substrates of ROP18 form a highly connected PPI network. TP53 is located as the most connected hub in the center of the PPI network. B, GO analysis demonstrated that 68 ROP18 targets (left panel), especially 32 of them with annotated PPI relationships (right panel), are significantly enriched in some biological functions, e.g. metabolic process, kinase activity/phosphorylation, response to growth factor, apoptotic process/cell death, and immune system process. C, ROP18 targets are over-represented in some signaling pathways. Examples of the insulin signaling and MAPK signaling pathways are shown. Identified ROP18 substrates are indicated by circles with GO terms annotated in different colors using the same code as A. D, using the M3 algorithm, ROP18 was found to specifically recognize an acidic phospho-motif, which is most similar to CSNK2A1. E, comparison of identified substrates using the protein microarray approach revealed 14 human kinases that share a significant portion of targets as ROP18. p values of the statistical significance of each human kinase are shown in the bottom panel.