Separate membrane targeting and anchoring domains function in the localization of the S. cerevisiae Cdc24p guanine nucleotide exchange factor

Curr Genet. 2004 May;45(5):257-64. doi: 10.1007/s00294-004-0485-9. Epub 2004 Feb 10.


The Saccharomyces cerevisiae Cdc24p guanine nucleotide exchange factor (GEF) activates the Cdc42p GTPase to a GTP-bound state. Cdc42p and Cdc24p co-localize at polarized growth sites during the cell cycle; and analysis of Cdc24p carboxyl-terminal truncation and site-specific mutations identified a 56-amino-acid domain as being necessary and sufficient for localization to these sites. This domain, however, was unable to anchor Cdc24p at these sites. Anchoring was restored by fusing the targeting domain to either the Cdc24p carboxyl-terminal PC domain that interacts with the Bem1p scaffold protein or the Cdc42p KKSKKCTIL membrane-anchoring domain. Mutant analysis and protein solubilization data indicated that anchoring required Bem1p, the Rsr1p/Bud1p GTPase, and the potential transmembrane protein YGR221Cp/Tos2p. These data are consistent with Cdc24p localization being a function of both membrane-specific targeting and subsequent anchoring within a multi-protein complex. Given the highly conserved roles of GEFs in Cdc42p signaling pathways, it is likely that similar targeting and anchoring mechanisms exist for Rho GEFs in other eukaryotes.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adaptor Proteins, Signal Transducing / chemistry
  • Amino Acid Sequence
  • Calcium / chemistry
  • Cell Cycle
  • Cell Cycle Proteins / chemistry*
  • Cell Cycle Proteins / genetics*
  • Cell Cycle Proteins / metabolism
  • Cell Membrane / metabolism*
  • DNA / chemistry
  • DNA Mutational Analysis
  • Detergents / pharmacology
  • Escherichia coli / metabolism
  • Gene Deletion
  • Genotype
  • Green Fluorescent Proteins / chemistry
  • Green Fluorescent Proteins / metabolism
  • Guanine Nucleotide Exchange Factors / chemistry*
  • Guanine Nucleotide Exchange Factors / genetics*
  • Guanine Nucleotide Exchange Factors / metabolism
  • Guanosine Triphosphate / chemistry
  • Immunoblotting
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Mutation
  • Plasmids / metabolism
  • Polymerase Chain Reaction
  • Protein Binding
  • Protein Structure, Tertiary
  • Recombinant Proteins / chemistry
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Saccharomyces cerevisiae Proteins / genetics*
  • Saccharomyces cerevisiae Proteins / metabolism
  • Signal Transduction
  • Subcellular Fractions / chemistry
  • Temperature


  • Adaptor Proteins, Signal Transducing
  • CDC24 protein, S cerevisiae
  • Cell Cycle Proteins
  • Detergents
  • Guanine Nucleotide Exchange Factors
  • Recombinant Proteins
  • Saccharomyces cerevisiae Proteins
  • BEM1 protein, S cerevisiae
  • Green Fluorescent Proteins
  • Guanosine Triphosphate
  • DNA
  • Calcium