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Nat Struct Mol Biol. 2016 Sep;23(9):821-9. doi: 10.1038/nsmb.3272. Epub 2016 Aug 1.

Clathrin-coat disassembly illuminates the mechanisms of Hsp70 force generation.

Author information

1
Department of Biochemistry and Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
2
Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland, USA.
3
Department for Macromolecular Structures, Centro Nacional de BiotecnologĂ­a (CNB-CSIC), Madrid, Spain.

Abstract

Hsp70s use ATP hydrolysis to disrupt protein-protein associations and to move macromolecules. One example is the Hsc70- mediated disassembly of the clathrin coats that form on vesicles during endocytosis. Here, we exploited the exceptional features of these coats to test three models-Brownian ratchet, power-stroke and entropic pulling-proposed to explain how Hsp70s transform their substrates. Our data rule out the ratchet and power-stroke models and instead support a collision-pressure mechanism whereby collisions between clathrin-coat walls and Hsc70s drive coats apart. Collision pressure is the complement to the pulling force described in the entropic pulling model. We also found that self-association augments collision pressure, thereby allowing disassembly of clathrin lattices that have been predicted to be resistant to disassembly. These results illuminate how Hsp70s generate the forces that transform their substrates.

PMID:
27478930
PMCID:
PMC5016234
DOI:
10.1038/nsmb.3272
[Indexed for MEDLINE]
Free PMC Article

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