title: Trafficking of vacuolar proteins: the crucial role of Arabidopsis vacuolar protein sorting 29 in recycling vacuolar sorting receptor.
abstract: The retromer is involved in recycling lysosomal sorting receptors in mammals. A component of the retromer complex in Arabidopsis thaliana, vacuolar protein sorting 29 (VPS29), plays a crucial role in trafficking storage proteins to protein storage vacuoles. However, it is not known whether or how vacuolar sorting receptors (VSRs) are recycled from the prevacuolar compartment (PVC) to the trans-Golgi network (TGN) during trafficking to the lytic vacuole (LV). Here, we report that VPS29 plays an essential role in the trafficking of soluble proteins to the LV from the TGN to the PVC. maigo1-1 (mag1-1) mutants, which harbor a knockdown mutation in VPS29, were defective in trafficking of two soluble proteins, Arabidopsis aleurain-like protein (AALP):green fluorescent protein (GFP) and sporamin:GFP, to the LV but not in trafficking membrane proteins to the LV or plasma membrane or via the secretory pathway. AALP:GFP and sporamin:GFP in mag1-1 protoplasts accumulated in the TGN but were also secreted into the medium. In mag1-1 mutants, VSR1 failed to recycle from the PVC to the TGN; rather, a significant proportion was transported to the LV; VSR1 overexpression rescued this defect. Moreover, endogenous VSRs were expressed at higher levels in mag1-1 plants. Based on these results, we propose that VPS29 plays a crucial role in recycling VSRs from the PVC to the TGN during the trafficking of soluble proteins to the LV.
authors.affiliation: Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea.
authors.forename: Hyangju
authors.initials: H
authors.lastname: Kang
authors.forename: Soo Youn
authors.initials: SY
authors.lastname: Kim
authors.forename: Kyungyoung
authors.initials: K
authors.lastname: Song
authors.forename: Eun Ju
authors.initials: EJ
authors.lastname: Sohn
authors.forename: Yongjik
authors.initials: Y
authors.lastname: Lee
authors.forename: Dong Wook
authors.initials: DW
authors.lastname: Lee
authors.forename: Ikuko
authors.initials: I
authors.lastname: Hara-Nishimura
authors.forename: Inhwan
authors.initials: I
authors.lastname: Hwang
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000235:genetics / Q000502:physiology; D014617:Vacuoles / Q000235:genetics / Q000378:metabolism*; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism; D021601:trans-Golgi Network / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C106564:ELP protein, Arabidopsis; C515611:Mag1 protein, Arabidopsis; D033921:Vesicular Transport Proteins