Premium
Topology and maturation of filamentous haemagglutinin suggest a new model for two‐partner secretion
Author(s) -
Mazar Joseph,
Cotter Peggy A.
Publication year - 2006
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/j.1365-2958.2006.05392.x
Subject(s) - biology , secretion , microbiology and biotechnology , cleavage (geology) , secretory protein , function (biology) , biochemistry , paleontology , fracture (geology)
Summary Two‐partner secretion (TPS) is the most widely distributed secretion pathway known. These systems export large exoproteins through highly conserved channel‐forming β‐barrel proteins. Filamentous haemagglutinin (FHA), expressed by Bordetella species, is the prototypical TPS family member. Here we show that the C‐terminus of mature FHA, as opposed to the N‐terminus as previously proposed, is exposed on the cell surface and is required for mediating adherence to cultured epithelial cells. We show that the C‐terminus of the FHA pro‐protein (FhaB) is required for FHA function in vitro and in vivo and we show that cleavage of FhaB to form FHA is not the mechanism by which FHA is released from the cell. Based on these data, we propose a new model for TPS. This model provides an explanation for the energetics of export of globular protein domains across membranes in the absence of ATP and it suggests a new mechanism for the control of protein folding.