Secretion of a protoxin post-translationally controlled by NaCl in a halotolerant yeast, Pichia farinosa.
The halotolerant yeast, Pichia farinosa KK1 secretes a killer toxin consisting of alpha (6.3 kDa) and beta (7.8 kDa) subunits, produced from a chromosomally encoded preprotoxin. In the presence of a high concentration of NaCl, a 26-kDa glycoprotein (gp26) that reacted with anti-beta-subunit antiserum was found to be secreted into the medium. Amino acid sequence analysis confirmed that gp26 is a protoxin generated by removal of the signal peptide from the preprotoxin. The purified gp26 did not have killer activity, suggesting that further processing is necessary for acquisition of this activity. Secretion of gp26 increased with increasing concentrations of NaCl in the medium and maximum secretion was observed at 2 M NaCl. Western blot analysis and RT-PCR showed that the secretion of gp26 is post-translationally controlled by NaCl.
National Food Research Institute, Ibaraki-ken, Japan. csuzuki@nfri.affrc.go.jp
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D000595:Amino Acid Sequence; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D055646:Killer Factors, Yeast; D008969:Molecular Sequence Data; D009183:Mycotoxins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D010843:Pichia / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D011498:Protein Precursors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012965:Sodium Chloride / Q000494:pharmacology*
D055646:Killer Factors, Yeast; D009183:Mycotoxins; D011498:Protein Precursors; D012965:Sodium Chloride