A constitutive mutation, phoT, of the repressible acid phosphatase synthesis with inability to transport inorganic phosphate in Saccharomyces cerevisiae

We studied ultrastructural localization of acid phosphatase in derepressed Saccharomyces cerevisiae cells transformed with a multicopy plasmid carrying either the wild-type PHO5 gene or a PHO5 gene deleted in the region overlapping the signal peptidase cleavage site. Wild-type enzyme was located in the cell wall, as was 50% of the modified protein, which carried high-mannose-sugar chains. The remaining 50% of the protein was active and core glycosylated, and it accumulated in the endoplasmic reticulum cisternae. The signal peptide remained uncleaved in both forms. Cells expressing the modified protein exhibited an exaggerated endoplasmic reticulum with dilated lumen.

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Saccharomyces Cerevisiae Acid Phosphatase

Molecular Biology and Genetic Engineering of Yeasts ◽

10.1201/9781351074735-16 ◽

2018 ◽

pp. 299-308

Author(s):

Henri Heslot ◽

Claude Gaillardin

Keyword(s):

Saccharomyces Cerevisiae ◽

Acid Phosphatase

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Signal peptide specificity in posttranslational processing of the plant protein phaseolin in Saccharomyces cerevisiae.

Molecular and Cellular Biology ◽

10.1128/mcb.7.1.121 ◽

1987 ◽

Vol 7 (1) ◽

pp. 121-128 ◽

Cited By ~ 15

Author(s):

J H Cramer ◽

K Lea ◽

M D Schaber ◽

R A Kramer

Keyword(s):

Saccharomyces Cerevisiae ◽

Acid Phosphatase ◽

Signal Peptide ◽

Regulatory Region ◽

Cellular Protein ◽

Proteolytic Processing ◽

Coding Region ◽

Molecular Weights ◽

Amino Terminal ◽

Acid Phosphatase Gene

We linked the cDNA coding region for the bean storage protein phaseolin to the promoter and regulatory region of the Saccharomyces cerevisiae repressible acid phosphatase gene (PHO5) in multicopy expression plasmids. Yeast transformants containing these plasmids expressed phaseolin at levels up to 3% of the total soluble cellular protein. Phaseolin polypeptides in S. cerevisiae were glycosylated, and their molecular weights suggested that the signal peptide had been processed. We also constructed a series of plasmids in which the phaseolin signal-peptide-coding region was either removed or replaced with increasing amounts of the amino-terminal coding region for acid phosphatase. Phaseolin polypeptides with no signal peptide were not posttranslationally modified in S. cerevisiae. Partial or complete substitution of the phaseolin signal peptide with that from acid phosphatase dramatically inhibited both signal peptide processing and glycosylation, suggesting that some specific feature of the phaseolin signal amino acid sequence was required for these modifications to occur. Larger hybrid proteins that included approximately one-half of the acid phosphatase sequence linked to the amino terminus of the mature phaseolin polypeptide did undergo proteolytic processing and glycosylation. However, these polypeptides were cleaved at several sites that are not normally used in the unaltered acid phosphatase protein.

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