BUD2 encodes a GTPase-activating protein for Bud1/Rsr1 necessary for proper bud-site selection in yeast

Nature. 1993 Sep 16;365(6443):269-74. doi: 10.1038/365269a0.


Cells of the budding yeast Saccharomyces cerevisiae bud at either axial or bipolar sites depending on their cell type. Bud-site selection directs both cell polarity and the cytoskeletal orientation during budding and is determined by at least five genes: BUD1/RSR1, BUD2, BUD3, BUD4 and BUD5. Mutants defective in BUD1, BUD2 or BUD5 choose bud sites randomly. Bud1 protein (Bud1p) has sequence similarity to Ras, a small GTP-binding protein, and Bud5p is similar to Cdc25p (refs 4, 5), a GDP-GTP exchange factor. Here we report that Bud2p is a GTPase-activating protein (GAP) for Bud1p with a sequence similar to the catalytic domain of rasGAPs, and that Bud2p purified from yeast stimulates GTP hydrolysis by Bud1p. Chromosomal deletion of BUD2 causes a random budding pattern but no obvious growth defect. Overexpression of BUD2 also causes a random budding pattern by wild-type cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cloning, Molecular
  • DNA, Fungal
  • Enzyme Activation
  • Fungal Proteins / genetics*
  • Fungal Proteins / metabolism
  • GTP Phosphohydrolase Activators*
  • GTP Phosphohydrolases / metabolism*
  • GTPase-Activating Proteins
  • Genes, Fungal*
  • Humans
  • Molecular Sequence Data
  • Mutation
  • Restriction Mapping
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / growth & development
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins*
  • Sequence Homology, Amino Acid


  • BUD2 protein, S cerevisiae
  • DNA, Fungal
  • Fungal Proteins
  • GTP Phosphohydrolase Activators
  • GTPase-Activating Proteins
  • Saccharomyces cerevisiae Proteins
  • GTP Phosphohydrolases

Associated data

  • GENBANK/L19162