Virtually every process in a cell is carried out by macromolecular complexes whose actions need to be perfectly orchestrated. The synchronization and regulation of these biological functions is indeed critical and is usually carried out by complex networks of transient protein interactions. Here, we review some of the many strategies that proteins in regulatory networks use to achieve the dynamic plasticity necessary to rapidly respond to diverse cellular needs. More specifically, we present recent work on the molecular bases of transient peptide-mediated interactions and the role that post-translational modifications and disordered regions might play. Finally, in light of some recent findings, we speculate on the possibility of a new regulatory code for intrinsically disordered proteins and the potential biophysical and functional advantages that disorder might provide.