Table II

Analysis of intrinsic sequence disorder

Summary of protein domain, intrinsic disorder, and 14-3-3 binding site analysis of 512 phosphorylation sites characterized on 141 cytosolic phosphoproteins from the double IMAC purification. Ser/Thr phosphorylation sites in the cytosolic phosphoproteome are significantly depleted in structural domains and significantly enriched in disordered regions of proteins.

No.%
Phosphoproteins (141 total)
    With Pfam-A domains11179
    With long (>40 residues) disordered regions13394a
Phosphorylation sites (512 total)
    Outside Pfam-A domains48294a
    In disordered regions43886
    Outside Pfam-A domains that are in disordered regions41995
    Potential 14-3-3 binding sites5811
  • a 16 out of the 32 phosphorylation sites mapped to Pfam domains are located in MAP2 projection domains, and as these domains are unstructured, at least 498 (97%) phosphorylation sites lie outside of structural domains in the cytosolic phosphoproteome.