582 / 2019-04-13 11:57:58

VPS41 is a unique subunit of HOPS complex in the regulation of vacuole trafficking.

HOPS complex,vacuole traffikcing,Prevacuolar compartment,Protein storage protein,Rab5,Rab7

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The homotypic fusion and vacuole protein sorting (HOPS) complex is a conserved multisubunit tethering complex in all the eukaryotic cells. Previous work has revealed that the HOPS subunit VPS41 was a new factor controlling pollen tube-stigma interaction. In this work, we investigated the regulatory mechanism of VPS41 at vegetative stage. We demonstrated that VPS41 displayed plant unique characteristics. VPS41 localized on subdomains of the tonoplast and a novel endomembrane compartment which did not share common features with the traditional early or late endosomal proteins. Upstream factors from Rab5 and Rab7 pathways competitively determined the endosomal and tonoplast localizations of VPS41, respectively. Genetic evidence revealed that VPS41 was essential for cargo sorting of AP-3, ER and Rab5 vacuole trafficking pathways but not required for the cargo in the Rab7 pathway. This is quite different form the conserved mechanism in yeast and mammalian cells in which the VPS41 homologous counterparts are recruited to the late endosome after Rab7 activation. We also showed that VPS41 exhibited plant unique functions independent of HOPS complex as VPS41ΔRING truncated protein disrupted the association with the other HOPS subunits but retained on the endosomes and the VPS41ΔRING-GFP seedlings only exhibited minor growth defects. Taken together, our results reveal that VPS41 is a unique subunit of HOPS complex that carry out plant specific functions in vacuole trafficking.