A novel phospholipid-binding protein from the yeast Saccharomyces cerevisiae with dual binding specificities for the transport GTPase Ypt7p and the Sec1-related Vps33p.
The gene product of the Saccharomyces cerevisiae open reading frame YDR229w (named IVY1 for: Interacting with Vps33p and Ypt7p) was found to interact with both the GTPase Ypt7p and the Sec1-related Vps33 protein. While deletion of IVY1 does not lead to any recognized change in phenotype, overexpression of Ivy1p leads to fragmentation of the vacuole, missorting of the vacuolar enzyme carboxypeptidase Y (CPY) to the exterior of the cell, and an accumulation of multivesicular bodies inside the cell. All effects caused by the overexpression of Ivy1p can be reset by simultaneously raising the amount of Vps33p. This suppression activity of Vps33p suggests that Ivy1p and Vps33p at least partially counteract the action of each other in the cell. The intracellular level of Ivy1p increases in cells approaching stationary growth phase at which part of the protein is located at the rim of the vacuole. In addition to its specific interactions with members of two regulatory protein families, Ivy1p in vitro shows a marked propensity for binding phospholipids with high affinity.
Lazar
Thomas
T
Department of Molecular Genetics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
Scheglmann
Dietrich
D
Gallwitz
Dieter
D
D000595:Amino Acid Sequence / Q000235:genetics; D001483:Base Sequence / Q000235:genetics; D029742:Caenorhabditis elegans Proteins; D002268:Carboxypeptidases / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D043402:Cathepsin A; D002478:Cells, Cultured; D022162:Cytoplasmic Vesicles / Q000378:metabolism / Q000648:ultrastructure; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D008854:Microscopy, Electron; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010641:Phenotype; D010743:Phospholipids / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D014617:Vacuoles / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D018076:DNA, Complementary; C475841:IVY1 protein, S cerevisiae; D018832:Molecular Chaperones; D010743:Phospholipids; D029701:Saccharomyces cerevisiae Proteins; C065454:VPS33 protein, S cerevisiae; D033921:Vesicular Transport Proteins; C102603:sip-1 protein, C elegans; D002268:Carboxypeptidases; D043402:Cathepsin A; C079005:YPT7 protein, S cerevisiae; D020691:rab GTP-Binding Proteins