The Saccharomyces cerevisiae MSI4 gene encodes the yeast counterpart of component A of Rab geranylgeranyltransferase.
We describe the isolation of MSI4 as a multicopy suppressor of ira1 (inhibitory regulator of Ras). We find it encodes a 66-kDa protein with three regions similar to component A of Rab geranylgeranyltransferase and Rab guanine nucleotide dissociation inhibitor. A gene disruption experiment showed that MSI4 is essential for cell growth. To investigate its functions further, we constructed a strain whose MSI4 is driven by the GAL1 promoter. This strain accumulated the endoplasmic reticulum precursor form of a vacuolar enzyme, carboxypeptidase Y, under the restrictive conditions. Moreover, we showed that the activity of geranylgeranyl-transferase for Ypt1p was very low in the mutant shifted to glucose medium. We propose that the MSI4 gene product is a yeast counterpart of component A of Rab geranylgeranyltransferase that is essential for Ypt1p to localize on membranes.
Fujimura
K
K
Department of Biology, Faculty of Science, University of Tokyo, Japan.
Tanaka
K
K
Nakano
A
A
Toh-e
A
A
D048868:Adaptor Proteins, Signal Transducing; D019883:Alkyl and Aryl Transferases; D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D002352:Carrier Proteins / Q000235:genetics*; D002451:Cell Compartmentation; D015794:Choroideremia / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D019204:GTP-Binding Proteins / Q000378:metabolism; D005800:Genes, Fungal; D016153:Genes, Suppressor; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D014166:Transferases / Q000235:genetics*; D020691:rab GTP-Binding Proteins
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004271:DNA, Fungal; C092439:MRS6 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014166:Transferases; D019883:Alkyl and Aryl Transferases; C075607:Rab geranylgeranyltransferase; D019204:GTP-Binding Proteins; C060755:YPT1 protein, S cerevisiae; D020691:rab GTP-Binding Proteins