Actin dynamics generate forces to deform the membrane and overcome the cell's high turgor pressure during clathrin-mediated endocytosis (CME) in yeast, but precise molecular details are still unresolved. Our previous models predicted that actin filaments of the endocytic meshwork continually polymerize and disassemble, turning over multiple times during an endocytic event, similar to other actin systems. We applied single-molecule speckle tracking in live fission yeast to directly measure molecular turnover within CME sites for the first time. In contrast with the overall ~20-sec lifetimes of actin and actin-associated proteins in endocytic patches, we detected single-molecule residence times around 1 to 2 sec, and similarly high turnover rates of membrane-associated proteins in CME. Furthermore, we find heterogeneous behaviors in many proteins' motions. These results indicate that endocytic proteins turn over up to five times during the formation of an endocytic vesicle, and suggest revising quantitative models of force production.
All data generated or analysed during this study are included in the manuscript and the supporting file "SuppFile4sets.mat" (Matlab data file).
- Michael M Lacy
- Julien Berro
- Michael M Lacy
- Michael M Lacy
- David Baddeley
- Julien Berro
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Pekka Lappalainen, University of Helsinki, Finland
© 2019, Lacy et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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