Phosphosites at unstructured termini. (a) Structure of the Rho GDP-dissociation inhibitor 2 in complex with RAC  (Protein Data Bank [PDB]: 1ds6). (b) Structure of the orphan nuclear receptor NR4A1 bound to DNA  (PDB: 1cit). In both panels the phosphosite-containing domains are colored in cyan and their interacting partners in light yellow. The modified sites are shown in space-filled representation. (c,d) Two examples of phosphorylations found in short linkers between domains within the human Zinc finger protein 174 and the mouse discs large homolog 4, respectively. Notice that, for the latter, the displayed boundaries of the PDZ domain correspond to those from the structural assignment and not to those defined by Pfam, because the latter did not include the carboxyl-terminus. A list with additional details on the examples, including links to the appropriate mtcPTM entries, can be found in Additional data file 1.