Trafficking of Vacuolar Proteins: The Crucial Role of Arabidopsis Vacuolar Protein Sorting 29 in Recycling Vacuolar Sorting Receptor

摘要

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 () are recycled from the prevacuolar compartment () to the trans-Golgi network () during trafficking to the lytic vacuole (). Here, we report that VPS29 plays an essential role in the trafficking of soluble proteins to the from the to the . 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 but not in trafficking membrane proteins to the or plasma membrane or via the secretory pathway. AALP:GFP and sporamin:GFP in mag1-1 protoplasts accumulated in the but were also secreted into the medium. In mag1-1 mutants, VSR1 failed to recycle from the to the ; rather, a significant proportion was transported to the ; 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 from the to the during the trafficking of soluble proteins to the href="#def1" rid="def1" class=" def">LV.