Serine Protease Autotransporters of the (SPATEs): Out and About and Chopping It Up.

Autotransporters are secreted proteins with multiple functions produced by a variety of Gram-negative bacteria. In , a subgroup of these autotransporters are the SPATEs (serine protease autotransporters of ). SPATEs play a crucial role in survival and virulence of pathogens such as and spp. and contribute to intestinal and extra-intestinal infections. These high molecular weight proteases are transported to the external milieu by the type Va secretion system and function as proteases with diverse substrate specificities and biological functions including adherence and cytotoxicity. Herein, we provide an overview of SPATEs and discuss recent findings on the biological roles of these secreted proteins, including proteolysis of substrates, adherence to cells, modulation of the immune response, and virulence in host models. In closing, we highlight recent insights into the regulation of expression of SPATEs that could be exploited to understand fundamental SPATE biology.