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EM of Pathogen Secretion Systems: Unfolded Protein Transport across Membranes in Action
Author(s) -
Marlovits Thomas
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.488.2
Subject(s) - secretion , membrane , intracellular , microbiology and biotechnology , biology , host (biology) , transport protein , bacteria , chemistry , biochemistry , ecology , genetics
We are focusing on two fundamental aspects in biology (1) assembly of multicomponent systems into functional nanomachines and (2) transport of proteins across membranes. Both are found in type three secretion systems (T3SS), which are required of bacterial secretion of proteins into the host that subvert the host antibacterial response in order to promote infection. These systems utilize a 3.5 MDa syringe‐like, membrane embedded “injectisome” containing an ~800 Å long needle complex thought to cross multiple membranes to connect the intracellular compartments of the bacteria and the host. The striking resemblance of the injectisome to a bona fide syringe, revealed by electron microscopy has led to the hypothesis that bacterial proteins are secreted through the needle complex into the host. I will discuss how and where substrates are passed through the T3SS and across two membranes by visualizing injectisomes in action and in situ.