A recurrent phospho-sumoyl switch in transcriptional repression and beyond.

How multisite posttranslational modification coordinates dynamic regulation of protein function is an issue fundamental to many biological processes. Related to this, a composite sequence motif has recently been identified that couples phosphorylation, sumoylation, and perhaps also deacetylation to control transcriptional repression in stress response, mitogen and nuclear hormone signaling, myogenesis, and neuronal differentiation. This motif is present in many proteins, integrates cellular signals from diverse pathways, and serves as a valuable signature for in silico identification of proteins regulated by adjacent phosphorylation and sumoylation.