Regulated proteolysis in bacterial development

protease; regulatory proteolysis; signal; morphogenesis; differentiation; cell cycle. Bacteria use proteases to control three types of events temporally and spatially during the processes of morphological development. These events are the destruction of regulatory proteins, activation of regulatory proteins, and pro-duction of signals. While some of these events are entirely cytoplasmic, others involve intramembrane proteolysis of a substrate, transmembrane signaling, or secretion. In some cases, multiple proteolytic events are organized into path-ways, for example turnover of a regulatory protein activates a protease that generates a signal. We review well-studied and emerging examples and identify recurring themes and important questions for future research. We focus pri-marily on paradigms learned from studies of model organisms, but we note connections to regulated proteolytic events that govern bacterial adaptation, biofilm formation and disassembly, and pathogenesis