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Organelle tethering, pore formation and SNARE compensation in the late endocytic pathway.

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Davis, Luther J 
Parkinson, Michael DJ  ORCID logo  https://orcid.org/0000-0001-8274-6794
Wartosch, Lena 

Abstract

To provide insights into the kiss-and-run and full fusion events resulting in endocytic delivery to lysosomes, we investigated conditions causing increased tethering and pore formation between late endocytic organelles in HeLa cells. Knockout of the soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) VAMP7 and VAMP8 showed, by electron microscopy, the accumulation of tethered lysosome-associated membrane protein (LAMP)-carrier vesicles around multivesicular bodies, as well as the appearance of 'hourglass' profiles of late endocytic organelles attached by filamentous tethers, but did not prevent endocytic delivery to lysosomal hydrolases. Subsequent depletion of the SNARE YKT6 reduced this delivery, consistent with it compensating for the absence of VAMP7 and VAMP8. We also investigated filamentous tethering between multivesicular bodies and enlarged endolysosomes following depletion of charged multi-vesicular body protein 6 (CHMP6), and provide the first evidence that pore formation commences at the edge of tether arrays, with pore expansion required for full membrane fusion.

Description

Keywords

Endosome, Lysosome, Membrane fusion, Endosomes, HeLa Cells, Humans, Lysosomes, Membrane Fusion, R-SNARE Proteins, SNARE Proteins

Journal Title

J Cell Sci

Conference Name

Journal ISSN

0021-9533
1477-9137

Volume Title

134

Publisher

The Company of Biologists

Rights

All rights reserved
Sponsorship
Medical Research Council (MR/R009015/1)