The inverse autotransporter family: Intimin, invasin and related proteins

Intimin and invasin are adhesins and central virulence factors of attaching and effacing bacteria, such as enterohaemorrhagic Escherichia coil, and enteropathogenic Yersiniae, respectively. These proteins are prototypes of a large family of adhesins distributed widely in Gram-negative bacteria. It is now evident that this protein family represents a previously unrecognized autotransporter secretion system, termed type ye secretion. In contrast to classical autotransport, where the transmembrane beta-barrel domain or translocation unit is C-terminal to the extracellular region or passenger domain, type ye-secreted proteins have an inverted topology with the passenger domain C-terminal to the translocation unit; hence the term inverse autotransporter. This minireview covers the recent advances in elucidating the structure and biogenesis of inverse autotransporters. (C) 2015 Elsevier GmbH. All rights reserved.