Abstract
Recent advances in the sequencing of whole genomes have given fascinating insights into the overall composition of the encoded proteins. Many of the amino acid sequences that have been deduced in this way have highly biased sequences and are predicted to be unfolded. A significant number of these sequences correspond to parts of functional proteins, and in a surprising number of cases, the unstructured regions correspond to the most relevant parts of the protein for function – the actual sites for the binding of activators, repressors, and other ligands. This is particularly true for proteins involved in signaling networks – that is, signal transduction, transcriptional activation, translation, and cell cycle regulation. The intrinsically disordered regions facilitate interactions with multiple binding partners and also provide a means for efficiently dissociating the complex after the signal has been transduced. This article briefly reviews some of the recent experimental evidence from our own and other labs, upon which these conclusions are based.