RRC ID 1873
Author Maruyama N, Mun LC, Tatsuhara M, Sawada M, Ishimoto M, Utsumi S.
Title Multiple vacuolar sorting determinants exist in soybean 11S globulin.
Journal Plant Cell
Abstract The sorting determinants of glycinin, a soybean (Glycine max) 11S globulin, which mediates protein targeting to the protein storage vacuole (PSV), were investigated in maturing soybean cotyledons by transient expression assays. A C-terminal stretch of 10 amino acids of A1aB1b, a glycinin group I subunit, was sufficient to direct green fluorescent protein (GFP) to the PSV. This peptide may correspond to a C-terminal vacuolar sorting determinant (ctVSD). Because functional inhibition of this putative ctVSD of A1aB1b did not block PSV sorting of A1aB1b, we used the three-dimensional structure of A1aB1b to identify candidates for a sequence-specific determinant (ssVSD). We found that the sequence downstream of disordered region 4 could direct GFP to the PSV and that Ile-297 is critical for sorting. However, functional inhibition of the ctVSD, combined with the Ile297Gly mutation, did not abolish the vacuolar sorting of A1aB1b, suggesting that A1aB1b has a third sorting determinant in addition to ctVSD and ssVSD. A glycinin group II subunit, A3B4, lacked a ctVSD but contained a VSD reminiscent of an ssVSD and an additional sorting determinant. We also demonstrate, by expression of dominant negative mutants of small GTPases and drug treatment experiments, that the trafficking of A1aB1b is COPII vesicle-dependent and wortmannin- and brefeldin A-sensitive.
Volume 18(5)
Pages 1253-73
Published 2006-5
DOI 10.1105/tpc.105.036376
PII tpc.105.036376
PMID 16617100
PMC PMC1456878
MeSH ADP-Ribosylation Factor 1 / metabolism Amino Acid Sequence Androstadienes / pharmacology Brefeldin A / pharmacology COP-Coated Vesicles / physiology Cotyledon / metabolism Globulins / chemistry* Globulins / genetics Globulins / metabolism Green Fluorescent Proteins / analysis Green Fluorescent Proteins / metabolism Molecular Sequence Data Plant Proteins / chemistry* Plant Proteins / genetics Plant Proteins / metabolism Protein Folding Protein Sorting Signals Protein Subunits / chemistry Protein Subunits / genetics Protein Subunits / metabolism Protein Transport / drug effects Recombinant Fusion Proteins / analysis Recombinant Fusion Proteins / metabolism Signal Transduction Soybean Proteins Soybeans / metabolism* Soybeans / ultrastructure Vacuoles / metabolism* Vacuoles / ultrastructure Wortmannin
IF 8.631
Times Cited 26
Arabidopsis / Cultured plant cells, genes pda04573