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PubMed · 15256598

A force-dependent switch reverses type IV pilus retraction.

Berenike Maier·Michael Koomey·Michael P Sheetz
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Abstract

Type IV pilus dynamics is important for virulence, motility, and DNA transfer in a wide variety of prokaryotes. The type IV pilus system constitutes a very robust and powerful molecular machine that transports pilus polymers as well as DNA through the bacterial cell envelope. In Neisseria gonorrhoeae, pilus retraction is a highly irreversible process that depends on PilT, an AAA ATPase family member. However, when levels of PilT are reduced, the application of high external forces (F = 110 +/- 10 pN) induces processive pilus elongation. At forces of >50 pN, single pili elongate at a rate of v = 350 +/- 50 nm/s. For forces of <50 pN, elongation velocity depends strongly on force and relaxation causes immediate retraction. Both pilus retraction and force-induced elongation can be modeled by chemical kinetics with same step length for the rate-limiting translocation step. The model implies that a force-dependent molecular switch can induce pilus elongation by reversing the retraction mechanism.

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Adenosine TriphosphatasesBacterial ProteinsDNA, BacterialFimbriae, BacterialKineticsMolecular Motor ProteinsNeisseria gonorrhoeaeStress, MechanicalTime FactorsJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.

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Berenike Maier, Michael Koomey, Michael P Sheetz. 2004-07-15. A force-dependent switch reverses type IV pilus retraction.. https://doi.org/10.1073/pnas.0402305101

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