Multiple pathways allow protein secretion across the bacterial outer membrane

Secretion of proteins across the bacterial outer membrane takes place via a variety of mechanisms from simple one-component systems to complex multico mponent pathways. Secretion pathways can be organized into evolutionarily a nd functionally related groups, which highlight their relationship with org anelle biogenesis. Recent work is beginning to reveal the structure and fun ction of various secretion components and the molecular mechanisms of secre tion.