Abstract
Seed storage proteins synthesized on rough ER are transported to protein storage vacuoles (PSVs) via vesicle-mediated pathway. AtVSR1, one of the vacuolar sorting receptors in Arabidopsis, plays an important role in the recognition of the vacuolar-targeting signal of the storage proteins.1) In atvsr1 seeds, the storage proteins are abnormally secreted to accumulate in the extracellular space. When a GFP-fusion protein with vacuolar-targeting signal was expressed in atvsr1 seeds, GFP fluorescence was observed in the extracellular space. By monitoring the GFP fluorescence, we screened for Arabidopsis mutants that had defects in the sorting machinery of storage proteins from EMS-mutagenized M2 seed population. These mutant seeds abnormally accumulated the precursors of storage proteins, pro12S globulins and pro2S albumins.
1)Shimada, T. Fuji, K. et al. (2003) Proc. Natl. Acad. Sci. USA. 100(26): 16095-100.
