PhosphoSerine/threonine binding domains: you can't pSERious?

The fundamental biological importance of protein phosphorylation is underlined by the existence of more than 500 protein kinase genes within the human genome. In many cases, phosphorylation on serine, threonine, and tyrosine residues creates binding surfaces for a variety of phospho-amino acid binding proteins/modules. Here, we review the insights into serine/threonine phosphorylation-dependent signal transduction processes provided by structures of several of these proteins and their complexes.