Regulation of Vesicle Formation

Abstract

This chapter addresses the regulation of outer membrane vesicles (OMVs) production in gram-negative bacteria; however, a brief section is dedicated to summarizing current knowledge of gram-positive membrane vesicles (MVs). To understand the molecular mechanisms of OMV formation, it is important to first review the structural differences between the cell envelopes of Gram-negative and Gram-positive bacteria. Despite intense interest and research in the field since the discovery of OMVs, the molecular mechanism of OMV formation has not been completely elucidated. Three main models for the mechanism of OMV formation have been proposed, which are not mutually exclusive. Processes regulated by quorum sensing (QS) include production of secondary metabolites and virulence factors, light production, biofilm formation, and OMV formation. The contribution of OMVs to biofilm structures is discussed in the chapter; however, specifically within the host, the propensity to form microcolonies and the role OMVs play during infection may reveal novel biofilm-related regulatory mechanisms of OMV formation within the host. Through the combined efforts of many investigators over the course of decades of research, much light has been shed on the highly conserved process of bacterial MV formation, though several questions remain unanswered. Regulatory schemes for OMV formation are actively being determined, and some of the future progress could be derived from collaboration with other research areas like QS and regulatory RNAs.