title: Transport of ricin and 2S albumin precursors to the storage vacuoles of Ricinus communis endosperm involves the Golgi and VSR-like receptors.
abstract: We have studied the transport of proricin and pro2S albumin to the protein storage vacuoles of developing castor bean (Ricinus communis L.) endosperm. Immunoelectron microscopy and cell fractionation reveal that both proteins travel through the Golgi apparatus and co-localize throughout their route to the storage vacuole. En route to the PSV, the proteins co-localize in large (>200 nm) vesicles, which are likely to represent developing storage vacuoles. We further show that the sequence-specific vacuolar sorting signals of both proricin and pro2SA bind in vitro to proteins that have high sequence similarity to members of the VSR/AtELP/BP-80 vacuolar sorting receptor family, generally associated with clathrin-mediated traffic to the lytic vacuole. The implications of these findings in relation to the current model for protein sorting to storage vacuoles are discussed.
authors.affiliation: Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Jolliffe
authors.forename: Joanna C
authors.initials: JC
authors.lastname: Brown
authors.forename: Ulla
authors.initials: U
authors.lastname: Neumann
authors.forename: Maïte
authors.initials: M
authors.lastname: Vicré
authors.forename: Angela
authors.initials: A
authors.lastname: Bachi
authors.forename: Chris
authors.initials: C
authors.lastname: Hawes
authors.forename: Aldo
authors.initials: A
authors.lastname: Ceriotti
authors.forename: Lynne M
authors.initials: LM
authors.lastname: Roberts
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Frigerio
mesh_terms: D055516:2S Albumins, Plant; D000595:Amino Acid Sequence; D052179:Antigens, Plant; D002367:Ricinus communis / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D012276:Ricin / Q000378:metabolism*; D014617:Vacuoles / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D055516:2S Albumins, Plant; C541551:2S storage protein, Ricinus communis; D052179:Antigens, Plant; D010446:Peptide Fragments; D010940:Plant Proteins; D012276:Ricin