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A translocator‐specific export signal establishes the translocator–effector secretion hierarchy that is important for type III secretion system function
Author(s) -
Tomalka Amanda G.,
Stopford Charles M.,
Lee PeiChung,
Rietsch Arne
Publication year - 2012
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12069
Subject(s) - biology , secretion , effector , hierarchy , function (biology) , translocator protein , microbiology and biotechnology , signal (programming language) , computational biology , biochemistry , immunology , computer science , inflammation , neuroinflammation , economics , market economy , programming language
Summary Type III secretion systems are used by many G ram‐negative pathogens to directly deliver effector proteins into the cytoplasm of host cells. To accomplish this, bacteria secrete translocator proteins that form a pore in the host‐cell membrane through which the effector proteins are then introduced into the host cell. Evidence from multiple systems indicates that the pore‐forming translocator proteins are exported before effectors, but how this secretion hierarchy is established is unclear. Here we used the P seudomonas aeruginosa translocator protein PopD as a model to identify its export signals. The N ‐terminal secretion signal and chaperone, PcrH , are required for export under all conditions. Two novel signals in PopD , one proximal to the chaperone binding site and one at the very C ‐terminus of the protein, are required for export of PopD before effector proteins. These novel export signals establish the translocator–effector secretion hierarchy, which in turn, is critical for the delivery of effectors into host cells.