storage vacuole as well as lytic vacuole. A knock out of AtVSR1 (an arabidopsis isoform of VSR) resulted in partial secretion of the precursors of all major classes of storage proteins in arabidopsis seeds (Shimada et al., 2003). Jolliffe et al. (2004) demonstrated both biochemically and by immunogold cyto- chemistry that in the endosperm of developing castor bean seeds that proricin and pro2S albumin pass through the Golgi and colocalise in large post-Golgi vesicles which probably fuse to generate a mature PSV. Interestingly, in vitro experiments demonstrated that both proricin and pro2SA bind to proteins that are similar to members of the VSR /AtELP/BP-80 vacu- olar sorting receptor family, indicating that VSR function may not be restricted to sorting proteins destined for the lytic vacuole.