Mechanistic and Structural Analysis of Type IV Secretion Systems
from: Bacterial Secreted Proteins: Secretory Mechanisms and Role in Pathogenesis (Edited by: Karl Wooldridge). Caister Academic Press, U.K. (2009)
Type IV secretion systems are multiprotein complexes that mediate the translocation of macromolecules (proteins, DNA or DNA-protein complexes) across the bacterial cell envelope into the extracellular medium or directly into recipient cells. This strategy is exploited for the delivery of effector molecules that modulate host cell interactions by bacterial pathogens and symbionts. Type IV secretion systems also mediate the translocation of DNA molecules from bacteria and the uptake of DNA into bacteria and thereby contribute to horizontal gene transfer. This review will discuss the state of knowledge on individual type IV secretion system components focusing on mechanistic and structural analyses. Based on these data, current models of the assembly of type IV secretion systems and of substrate translocation across the bacterial cell envelope will be presented. The review will conclude with a discussion of the remaining challenges, the future opportunities and novel approaches aimed at deciphering the function of these versatile macromolecule transporters read more ...