title: A recycling-defective vacuolar sorting receptor reveals an intermediate compartment situated between prevacuoles and vacuoles in tobacco.
abstract: Plant vacuolar sorting receptors (VSRs) display cytosolic Tyr motifs (YMPL) for clathrin-mediated anterograde transport to the prevacuolar compartment. Here, we show that the same motif is also required for VSR recycling. A Y612A point mutation in Arabidopsis thaliana VSR2 leads to a quantitative shift in VSR2 steady state levels from the prevacuolar compartment to the trans-Golgi network when expressed in Nicotiana tabacum. By contrast, the L615A mutant VSR2 leaks strongly to vacuoles and accumulates in a previously undiscovered compartment. The latter is shown to be distinct from the Golgi stacks, the trans-Golgi network, and the prevacuolar compartment but is characterized by high concentrations of soluble vacuolar cargo and the rab5 GTPase Rha1(RabF2a). The results suggest that the prevacuolar compartment matures by gradual receptor depletion, leading to the formation of a late prevacuolar compartment situated between the prevacuolar compartment and the vacuole.
authors.affiliation: Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom.
authors.forename: Ombretta
authors.initials: O
authors.lastname: Foresti
authors.forename: David C
authors.initials: DC
authors.lastname: Gershlick
authors.forename: Francesca
authors.initials: F
authors.lastname: Bottanelli
authors.forename: Eric
authors.initials: E
authors.lastname: Hummel
authors.forename: Chris
authors.initials: C
authors.lastname: Hawes
authors.forename: Jürgen
authors.initials: J
authors.lastname: Denecke
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D002451:Cell Compartmentation; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D017354:Point Mutation; D014026:Nicotiana / Q000378:metabolism*; D014617:Vacuoles / Q000378:metabolism*