The AP-3 adaptor complex is required for vacuolar function in Arabidopsis

• Published in: Cell research 2011-12, Vol.21 (12), p.1711-1722
• Main Authors: Zwiewka, Marta, Feraru, Elena, Möller, Barbara, Hwang, Inhwan, Feraru, Mugurel I, Kleine-Vehn, Jürgen, Weijers, Dolf, Friml, Jiří
• Format: Article
• Language: English
• Subjects: 631/449/448/2024; 631/45; Adaptor Protein Complex 3 - metabolism; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; auxin efflux carrier; Biomedical and Life Sciences; Cell Biology; cell polarity; clathrin; Clathrin - metabolism; Dynamins - metabolism; endocytic pathway; Immunoprecipitation; Life Sciences; lytic vacuoles; Mammals; Mutants; Original; original-article; plant-cells; prevacuolar compartment; protein complex; Protein Subunits - metabolism; Protein Transport; Proteins; Trafficking; Vacuoles - metabolism; vesicle formation; Yeasts; 拟南芥; 液泡; 真核细胞; 突变体; 绿色荧光蛋白; 蛋白质; 适配器
• ISSN: 1001-0602; 1748-7838
• DOI: 10.1038/cr.2011.99

Subcellular trafficking is required for a multitude of functions in eukaryotic cells. It involves regulation of cargo sorting, vesicle formation, trafficking and fusion processes at multiple levels. Adaptor protein （AP） complexes are key regulators of cargo sorting into vesicles in yeast and mammals but their existence and function in plants have not been demonstrated. Here we report the identification of the protein-affected trafficking 4 （pat4） mutant defective in the putative 6 subunit of the AP-3 complex, pat4 and pat2, a mutant isolated from the same GFP imaging-based for- ward genetic screen that lacks a functional putative AP-3 β, as well as dominant negative AP-3 μ transgenic lines dis- play undistinguishable phenotypes characterized by largely normal morphology and development, but strong intra- cellular accumulation of membrane proteins in aberrant vacuolar structures. All mutants are defective in morphol- ogy and function of lytic and protein storage vacuoles （PSVs） but show normal sorting of reserve proteins to PSVs. Immunoprecipitation experiments and genetic studies revealed tight functional and physical associations of putative AP-3 β and AP-3 δ subunits. Furthermore, both proteins are closely linked with putative AP-3μvand σ subunits and several components of the clathrin and dynamin machineries. Taken together, these results demonstrate that AP complexes, similar to those in other eukaryotes, exist in plants, and that AP-3 plays a specific role in the regulation of biogenesis and function of vacuoles in plant ceils.