1. Enrichment of sequence disorder in the cytosolic phosphoproteome.
Enrichment of sequence disorder in the cytosolic phosphoproteome. The sequence composition of the data set of cytosolic phosphoproteins was compared with proteins in the entire Swiss-Prot database (A) and 825 UniProt M. musculus proteins (annotated as being expressed in the brain and located in the cytoplasm (UP-mbc)) (B) using Composition Profiler software. In addition, this set of UP-mbc proteins was compared with the entire Swiss-Prot database to determine the enrichment of disorder of these proteins due to their subcellular localization. The ratio of significant enrichment (p < 0.01) is color-coded according to the propensity of amino acids to promote protein disorder (red) or promote protein order (blue). It can be clearly seen that the cytosolic phosphoproteome is enriched in most disorder-promoting and depleted in most order-promoting amino acids when compared with the Swiss-Prot database as well as the UP-mbc data set, which is representative of the starting material (mouse brain cytosolic extract) used for the phosphopurifications. This UP-mbc data set also shows disorder enrichment compared with the Swiss-Prot database indicating that cytosolic proteins tend to be more disordered than proteins in other cellular compartments, and the enrichment of disorder between the cytosolic phosphoproteome and the UP-mbc data set is likely because they are phosphoproteins. Error bars represent fractional differences of the standard deviations of observed relative frequencies of the bootstrap samples.
Mark O. Collins et al. Mol Cell Proteomics 2008;7:
© 2008 The American Society for Biochemistry and Molecular Biology