Accumulation of exoglucanase activity in yeast secretory mutants blocked at the endoplasmic reticulum level.
Saccharomyces cerevisiae HMSF-176 (sec 18), a thermosensitive secretory mutant blocked at the endoplasmic reticulum (ER) level, drastically increased its osmotic sensitivity when grown at the restrictive temperature of 37 degrees C in high glucose concentration. This fact led to the erroneous interpretation that glucanases were inactive when localized in the ER. The development of a suitable osmotic stabilizer now indicates that sec 18 accumulates exoglucanase activity. Another ER-blocked mutant behaved in a similar way. All the accumulated exoglucanase was found in a soluble form. By contrast, a significant portion of the accumulated invertase remained in a membrane-bound form.
Hernández
L M
LM
Olivero
I
I
Ramírez
M
M
Larriba
G
G
D004721:Endoplasmic Reticulum / Q000201:enzymology; D005959:Glucosidases / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000378:metabolism; D009154:Mutation; D009995:Osmosis; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D012995:Solubility; D013696:Temperature; D043324:beta-Fructofuranosidase; D001617:beta-Glucosidase / Q000235:genetics / Q000378:metabolism*
D005959:Glucosidases; D006026:Glycoside Hydrolases; D001617:beta-Glucosidase; D043324:beta-Fructofuranosidase