Kölling, R. | Search bioRxiv

bioRxiv2023

The sorting nexin requirement of the Vps68 recycling signal is context dependent

Withdrawal statementThe author has withdrawn this manuscript because the central statement of the article that "The sorting nexin requirement of the Vps68 recycling signal is context dependent" proved to be incorrect. Newer results show that Vps68 recycling is indeed retromer dependent. The effect of retromer on Vps68 recycling was overlooked due to use of an expression construct, where sfGFP-Vps68 was about 5-fold overexpressed. This overexpression led to accumulation of sfGFP-Vps68 at the vacuolar membrane, which obscured the effect of the retromer deletion. Further, it turned out that Dcr2 is not involved in Vps68 recycling. The DCR2 open reading frame partially overlaps with the VPS38 gene, coding for a subunit of PI-3 kinase. The observed phenotypes of the DCR2 deletion can thus be totally attributed to the simultaneous loss of Vps38 function. A corrected version of the manuscript has been published in Biology Open (DOI: 10.1242/bio.062518). Therefore, the authors do not wish this work to be cited as a reference for the project.

cell biology↗

bioRxiv2022

Vps68 cooperates with ESCRT-III in intraluminal vesicle formation

The endosomal sorting complex required for transport (ESCRT)-III mediates budding and abscission of intraluminal vesicles (ILVs) into multivesicular endosomes. To further define the role of the ESCRT-III associated protein Mos10/Vps60 in ILV formation, we screened for new interaction partners by SILAC/MS. Here, we focused on the newly identified interaction partner Vps68. Our data suggest that Vps68 cooperates with ESCRT-III in ILV formation. The deletion of VPS68 caused a sorting defect similar to the SNF7 deletion, when the cargo load was high. The composition of ESCRT-III was altered, the level of core components was higher and the level of associated proteins was lower in the deletion strain. This suggests that a shift occurs from an active complex to a disassembly competent complex and that this shift is blocked in the{Delta} vps68 strain. We present evidence that during this shift Snf7 is replaced by Mos10. Vps68 has an unusual membrane topology. Two of its potential membrane helices are amphipathic helices localized to the luminal side of the endosomal membrane. Based on this membrane topology we propose that Vps68 and ESCRT-III cooperate in the abscission step by weakening the luminal and cytosolic leaflets of the bilayer at the abscission site.

molecular biology↗