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A bifunctional ATPase drives tad pilus extension and retraction
Courtney K Ellison1, Jingbo Kan2,3, Jennifer L Chlebek1
1Department of Biology, Indiana University, 1001 E. 3rd Street, Bloomington, IN 47405, USA.
Science Advances
|January 4, 2020
Summary
A single motor protein, CpaF, powers both the extension and retraction of tight adherence (tad) pili. This bifunctional adenosine triphosphatase (ATPase) drives these dynamic fiber movements through adenosine 5'-triphosphate (ATP) hydrolysis.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Prokaryotic motors utilize secretion motor adenosine triphosphatases (ATPases) for dynamic fiber extension/retraction.
- Tight adherence (tad) pili are crucial for bacterial surface sensing and biofilm formation.
- The mechanism of tad pili retraction, lacking a dedicated motor ATPase, was previously unknown.
Purpose of the Study:
- To elucidate the mechanism behind tad pili retraction.
- To identify the molecular components responsible for both pilus extension and retraction.
Main Methods:
- Investigated the role of the bifunctional pilus motor ATPase, CpaF.
- Analyzed the effects of mutations within CpaF on pilus motor activity.
- Measured adenosine 5 -triphosphate (ATP) hydrolysis rates and retraction force.
Main Results:
- CpaF was identified as a bifunctional ATPase driving both pilus extension and retraction.
- Mutations in CpaF led to decreased rates of both extension and retraction.
- Reduced ATP hydrolysis and retraction force directly correlated with CpaF mutations.
Conclusions:
- A single motor ATPase, CpaF, is responsible for the bidirectional movement of tad pili.
- CpaF utilizes adenosine 5 -triphosphate (ATP) hydrolysis to power both extension and retraction.
- This finding resolves the mystery of tad pili retraction mechanism.
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