title: Secretion of miraculin through the function of a signal peptide conserved in the Kunitz-type soybean trypsin inhibitor family.
abstract: Miraculin, a glycoprotein that modifies sour tastes into sweet ones, belongs to the Kunitz-type soybean trypsin inhibitor (STI) family. To clarify the functional relation of miraculin with Kunitz-type STIs, we investigated its subcellular localization and trypsin inhibitory activity. In transgenic Arabidopsis thaliana, miraculin, fused to yellow fluorescent protein, localized to and outside the plasma membrane depending on the putative secretion signal peptide. When transgenic seedlings were cultured in liquid medium, miraculin was present in the supernatant only after cellulase treatment. No trypsin inhibitory activity was detected in native or recombinant miraculin. In conclusion, miraculin is secreted outside the plasma membrane through the function of a signal peptide, conserved in Kunitz-type STIs, whereas its trypsin inhibitory activity may be lost during its evolution.
authors: Department of Food Science and Nutrition, Nara Women's University, Nara 630-8506, Japan.
authors: Ayako
authors: A
authors: Takai
authors: Makiko
authors: M
authors: Satoh
authors: Tomomi
authors: T
authors: Matsuyama
authors: Akane
authors: A
authors: Ito
authors: Rieko
authors: R
authors: Nakata
authors: Takashi
authors: T
authors: Aoyama
authors: Hiroyasu
authors: H
authors: Inoue
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics; D002462:Cell Membrane / Q000378:metabolism; D002480:Cellulase / Q000378:metabolism; D017124:Conserved Sequence; D006023:Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D042541:Intracellular Space / Q000378:metabolism; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D021382:Protein Sorting Signals; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014360:Trypsin Inhibitor, Kunitz Soybean / Q000737:chemistry* / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D010940:Plant Proteins; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; D014360:Trypsin Inhibitor, Kunitz Soybean; D002480:Cellulase