Requirement of the propeptide for in vivo formation of active yeast carboxypeptidase Y

TY - JOUR

T1 - Requirement of the propeptide for in vivo formation of active yeast carboxypeptidase Y

AU - Ramos, C

AU - Winther, Jakob R.

AU - Kielland-Brandt, Morten

PY - 1994

Y1 - 1994

N2 - Deletions have been constructed in the region encoding the 91-amino acid propeptide of the vacuolar enzyme carboxypeptidase Y of Saccharomyces cerevisiae, and in vivo effects of these mutations on the intracellular transport of the mutant proenzymes have been examined. Deletions did not include the vacuolar targeting signal, and none of the mutated forms of procarboxypeptidase Y was found to be secreted. All deletions, however, resulted in a decreased rate of transport of the truncated proenzymes from the endoplasmic reticulum to the Golgi apparatus. Up to 29 residues close to the N terminus can be removed without completely eliminating transport of the mutated proenzymes to the vacuole. However, the C-terminal part of the propeptide contains elements which are essential, since two small deletions, of 9 and 15 residues, respectively, within this area resulted in loss of carboxypeptidase Y activity. This region is, however, not sufficient for efficient formation of active carboxypeptidase Y, since truncated precursors in which the vacuolar targeting signal was fused to the C-terminal part of the proregion did not give rise to active enzyme. Based on the results, we propose that the carboxypeptidase Y propeptide plays an essential role in guiding the proper folding of the protein in vivo and that many parts of the propeptide contribute, in an additive way, to this function.

AB - Deletions have been constructed in the region encoding the 91-amino acid propeptide of the vacuolar enzyme carboxypeptidase Y of Saccharomyces cerevisiae, and in vivo effects of these mutations on the intracellular transport of the mutant proenzymes have been examined. Deletions did not include the vacuolar targeting signal, and none of the mutated forms of procarboxypeptidase Y was found to be secreted. All deletions, however, resulted in a decreased rate of transport of the truncated proenzymes from the endoplasmic reticulum to the Golgi apparatus. Up to 29 residues close to the N terminus can be removed without completely eliminating transport of the mutated proenzymes to the vacuole. However, the C-terminal part of the propeptide contains elements which are essential, since two small deletions, of 9 and 15 residues, respectively, within this area resulted in loss of carboxypeptidase Y activity. This region is, however, not sufficient for efficient formation of active carboxypeptidase Y, since truncated precursors in which the vacuolar targeting signal was fused to the C-terminal part of the proregion did not give rise to active enzyme. Based on the results, we propose that the carboxypeptidase Y propeptide plays an essential role in guiding the proper folding of the protein in vivo and that many parts of the propeptide contribute, in an additive way, to this function.

KW - Alleles

KW - Amino Acid Sequence

KW - Base Sequence

KW - Carboxypeptidases

KW - Cathepsin A

KW - DNA Restriction Enzymes

KW - Enzyme Precursors

KW - Genes, Fungal

KW - Molecular Sequence Data

KW - Mutagenesis, Site-Directed

KW - Oligodeoxyribonucleotides

KW - Restriction Mapping

KW - Saccharomyces cerevisiae

KW - Saccharomyces cerevisiae Proteins

KW - Sequence Deletion

M3 - Journal article

C2 - 8120064

SN - 0021-9258

VL - 269

SP - 7006

EP - 7012

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

IS - 9

ER -