In situ architecture, function, and evolution of a contractile injection system

Abstract

Identification of a new injection system To interact with other cells, bacteria use contractile machines that function similarly to membrane-puncturing bacteriophages. The so-called type 6 secretion system (T6SS) functions from inside a bacterial cell. Böck et al. used modern electron microscopy methods and functional assays to resolve the structure and function of a T6SS in the cellular context. They identified three modules and showed large-scale structural changes upon firing. T6SSs are organized in multibarrel gun-like arrays and may contribute to the survival of bacteria inside their host. Science , this issue p. 713