Discerning evolutionary trends in post-translational modification and the effect of intrinsic disorder: Analysis of methylation, acetylation and ubiquitination sites in human proteins
Fig 3
Distribution of PTM sites in ordered and disordered regions of human proteins for various subsets of the data.
(A) Distribution of MAU and phosphorylation sites in folding on binding (FB) regions and the percentage distribution of sites in FB non-FB/unclassified regions. Enrichment analysis is performed for the FB set as a sample of total ordered or disordered regions. Due to the limited experimental data, other PTM sites were detected only at very low levels or were not present: nitrosylated cysteines 2 sites, O-linked glycosylation (serine, 1 site and threonine, 5 sites), prenylated cysteine (2 sites), sulfated tyrosine (2 sites) and sumoylated lysines (24 sites), whereas carboxylation, myristoylation, palmitoylation sites are not present in the FB regions. We used hypergeometric probability tests to perform the enrichment/depletion analyses of PTM sites in FB regions. The critical P-value to test the significance is P<0.0014 (to correct for multiple hypotheses). (B) Distribution of MAU and phosphorylation sites in homopeptides. The enrichment and depletion analyses are calculated for homopeptides present in the ordered (olive green) and disordered (peach) regions. The statistical test and critical P-value is as for part (A). (C) Distribution of MAU and phosphorylation sites in Human prion-like proteins (grey). Enrichment analysis is performed for lysines or arginines in the prion-like protein set as a sample of total lysines or arginines in the disordered set, as appropriate. The statistical test and critical P-value is as for part (B).