Endoplasmic reticulum targeting and glycosylation of hybrid proteins in transgenic tobacco.
The correct compartmentation of proteins to the endomembrane system, mitochondria, or chloroplasts requires an amino-terminal signal peptide. The major tuber protein of potato, patatin, has a signal peptide in common with many other plant storage proteins. When the putative signal peptide of patatin was fused to the bacterial reporter protein beta-glucuronidase, the fusion proteins were translocated to the endoplasmic reticulum in planta and in vitro. In addition, translocated beta-glucuronidase was modified by glycosylation, and the signal peptide was correctly processed. In the presence of an inhibitor of glycosylation, tunicamycin, the enzymatically active form of beta-glucuronidase was assembled in the endoplasmic reticulum. This is the first report of targeting a cytoplasmic protein to the endoplasmic reticulum of plants using a signal peptide.
Iturriaga
G
G
Institute of Plant Science Research, Cambridge Laboratory, United Kingdom.
Jefferson
R A
RA
Bevan
M W
MW
D000595:Amino Acid Sequence; D002265:Carboxylic Ester Hydrolases; D004591:Electrophoresis, Polyacrylamide Gel; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D006031:Glycosylation; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D011499:Protein Processing, Post-Translational; D021382:Protein Sorting Signals / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014026:Nicotiana / Q000378:metabolism*; D014415:Tunicamycin / Q000494:pharmacology
D010940:Plant Proteins; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; C043222:patatin protein, Solanum tuberosum; D014415:Tunicamycin; D002265:Carboxylic Ester Hydrolases; D005966:Glucuronidase