Overproduction of Mpd2p suppresses the lethality of protein disulfide isomerase depletion in a CXXC sequence dependent manner.
The third multicopy suppressor gene of the PDI1 deletion from Saccharomyces cerevisiae, MPD2, was isolated and characterized. The MPD2 gene encodes a protein with a putative signal sequence, ER retention signal, and a disulfide isomerase active site like sequence. The amino acid sequence around the active site like sequence is similar to the thioredoxin-like domains of PDI and PDI related proteins, although the similarity is comparatively low. A delta-pdi1 strain over-producing Mpd2p showed slow growth and was sensitive to 1 mM dithiothreitol. Mpd2p can be detected in wild type cells and is a glycoprotein. Although the MPD2 gene was not essential for growth, overexpression of the gene partially restored the maturation defect of carboxypeptidase Y caused by the PDI1 deletion. Mutagenesis analysis revealed that Mpd2p can compensate for the loss of PDI with its CXXC sequence.
Tachikawa
H
H
Department of Applied Biological Science, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Japan.
Funahashi
W
W
Takeuchi
Y
Y
Nakanishi
H
H
Nishihara
R
R
Katoh
S
S
Gao
X D
XD
Mizunaga
T
T
Fujimoto
D
D
D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D002268:Carboxypeptidases / Q000096:biosynthesis / Q000235:genetics; D043402:Cathepsin A; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D016153:Genes, Suppressor; D008969:Molecular Sequence Data; D005810:Multigene Family; D019704:Protein Disulfide-Isomerases / Q000096:biosynthesis* / Q000235:genetics* / Q000302:isolation & purification; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics*
D002268:Carboxypeptidases; D043402:Cathepsin A; D019704:Protein Disulfide-Isomerases