title: A soluble acid invertase is directed to the vacuole by a signal anchor mechanism.
abstract: Enzyme activities in the vacuole have an important impact on the net concentration of sucrose. In sugarcane (Saccharum hybrid), immunolabelling demonstrated that a soluble acid invertase (β-fructofuranosidase; EC 3.2.1.26) is present in the vacuole of storage parenchyma cells during sucrose accumulation. Examination of sequences from sugarcane, barley and rice showed that the N-terminus of the invertase sequence contains a signal anchor and a tyrosine motif, characteristic of single-pass membrane proteins destined for lysosomal compartments. The N-terminal peptide from the barley invertase was shown to be capable of directing the green fluorescent protein to the vacuole in sugarcane cells. The results suggest that soluble acid invertase is sorted to the vacuole in a membrane-bound form.
authors.affiliation: CSIRO Plant Industry, Queensland Bioscience Precinct, 306 Carmody Road, St. Lucia, Queensland 4067, Australia. Anne.Rae@csiro.au
authors.forename: Anne L
authors.initials: AL
authors.lastname: Rae
authors.forename: Rosanne E
authors.initials: RE
authors.lastname: Casu
authors.forename: Jai M
authors.initials: JM
authors.lastname: Perroux
authors.forename: Mark A
authors.initials: MA
authors.lastname: Jackson
authors.forename: Christopher P L
authors.initials: CP
authors.lastname: Grof
mesh_terms: D000595:Amino Acid Sequence; D002467:Cell Nucleus; D003593:Cytoplasm; D006601:Hexoses / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000378:metabolism*; D021381:Protein Transport; D031786:Saccharum / Q000201:enzymology*; D020539:Sequence Analysis, Protein; D013395:Sucrose / Q000378:metabolism; D014617:Vacuoles / Q000201:enzymology*; D043324:beta-Fructofuranosidase / Q000378:metabolism*
chemical_list: D006601:Hexoses; D008565:Membrane Proteins; D010940:Plant Proteins; D013395:Sucrose; D043324:beta-Fructofuranosidase