ATG23, a novel gene required for maturation of proaminopeptidase I, but not for autophagy.
In rich media proaminopeptidase I is targeted to the vacuole via the Cvt pathway and during starvation via autophagy. We here identify Atg23 (Ylr431c), a protein of so far unknown function, as a novel component essential for proaminopeptidase I maturation under non-starvation conditions. Maturation of proaminopeptidase I takes place in starved atg23Delta cells. Selective vacuolar targeting of the autophagosomal marker GFP-Aut7 and the accumulation of autophagic bodies during starvation in the presence of phenylmethylsulfonyl fluoride suggest that autophagy occurs in atg23Delta cells but at a reduced rate. In atg23Delta cells mature vacuolar carboxypeptidase Y is present and accumulation of quinacrine suggests no significant defect in vacuolar acidification. Furthermore, growth of atg23Delta cells on nitrocellulose detects no significant secretion of carboxypeptidase Y.
Meiling-Wesse
Khuyen
K
Center of Biochemistry and Molecular Cell Biology, Georg-August-University, Heinrich-Dueker-Weg 12, D-37073 Göttingen, Germany.
Bratsika
Fotini
F
Thumm
Michael
M
D000626:Aminopeptidases / Q000235:genetics*; D001343:Autophagy; D000071183:Autophagy-Related Proteins; D001483:Base Sequence; D017931:DNA Primers; D010450:Endopeptidases / Q000378:metabolism; D011498:Protein Precursors / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D014617:Vacuoles / Q000201:enzymology
C480170:Atg23 protein, S cerevisiae; D000071183:Autophagy-Related Proteins; D017931:DNA Primers; D011498:Protein Precursors; D029701:Saccharomyces cerevisiae Proteins; D010450:Endopeptidases; D000626:Aminopeptidases; C450422:proaminopeptidase I