Protein phosphorylation in bacterial signal transduction

Background: Protein phosphorylation has emerged as one of the major post translational modifications in bacteria, involved in regulating a myriad of physiological processes. In a complex and dynamic system such as the bacterial cell, connectivity of its components accounts for a number of emergent properties. This article is part of a Special Issue entitled: Systems Biology of Microorganisms. Scope of review: This review focuses on the implications of bacterial protein phosphorylation in cell signaling and regulation and highlights the connections and cross talk between various signaling pathways: bacterial two-component systems and serine/threonine kinases, but also the interference between phosphorylation and other post-translational modifications (methylation and acetylation). Major conclusions: Recent technical developments in high accuracy mass spectrometry have profoundly transformed proteomics, and today exhaustive site-specific phosphoproteomes are available for a number of bacterial species. Nevertheless, prediction of phosphorylation sites remains the main guide for many researchers, so we discuss the characteristics, limits and advantages of available phosphorylation predictors. General significance: The advent of quantitative phosphoproteomics has brought the field on the doorstep of systems biology, but a number of challenges remain before the bacterial phosphorylation networks can be efficiently modeled and their physiological role understood. This article is part of a Special Issue entitled: Systems Biology of Microorganisms. (C) 2011 Elsevier B.V. All rights reserved.