Dynamic relocalization of the cytosolic type III secretion system components prevents premature protein secretion at low external pH

Stephan Wimmi, Alexander Balinovic, Hannah Jeckel, Lisa Selinger, Dimitrios Lampaki, Emma Eisemann, Ina Meuskens, Dirk Linke, Knut Drescher, Ulrike Endesfelder, Andreas Diepold

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Received Date: 27th March 20

Many bacterial pathogens use a type III secretion system (T3SS) to manipulate host cells. Protein secretion by the T3SS injectisome is activated upon contact to any host cell, and it has been unclear how premature secretion is prevented during infection. We found that in gastrointestinal pathogens, cytosolic injectisome components are temporarily released from the proximal interface of the injectisome at low external pH, preventing protein secretion in acidic environments, such as the stomach. In Yersinia enterocolitica, low external pH is detected in the periplasm and leads to a partial dissociation of the inner membrane injectisome component SctD, which in turn causes the dissociation of the cytosolic T3SS components. This effect is reversed upon restoration of neutral pH, allowing a fast activation of the T3SS at the native target regions within the host. These findings indicate that the cytosolic components form an adaptive regulatory interface, which regulates T3SS activity in response to environmental conditions.

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This is an abstract of a preprint hosted on an independent third party site. It has not been peer reviewed but is currently under consideration at Nature Communications.

Nature Communications

Nature Research, Springer Nature