Yeast genes controlling responses to topogenic signals in a model transmembrane protein.

Abstract

Yeast protein insertion orientation (PIO) mutants were isolated by selecting for growth on sucrose in cells in which the only source of invertase is a C-terminal fusion to a transmembrane protein. Only the fraction with an exocellular C terminus can be processed to secreted invertase and this fraction is constrained to 2-3% by a strong charge difference signal. Identified pio mutants increased this to 9-12%. PIO1 is SPF1, encoding a P-type ATPase located in the endoplasmic reticulum (ER) or Golgi. spf1-null mutants are modestly sensitive to EGTA. Sensitivity is considerably greater in an spf1 pmr1 double mutant, although PIO is not further disturbed. Pmr1p is the Golgi Ca(2+) ATPase and Spf1p may be the equivalent ER pump. PIO2 is STE24, a metalloprotease anchored in the ER membrane. Like Spf1p, Ste24p is expressed in all yeast cell types and belongs to a highly conserved protein family. The effects of ste24- and spf1-null mutations on invertase secretion are additive, cell generation time is increased 60%, and cells become sensitive to cold and to heat shock. Ste24p and Rce1p cleave the C-AAX bond of farnesylated CAAX box proteins. The closest paralog of SPF1 is YOR291w. Neither rce1-null nor yor291w-null mutations affected PIO or the phenotype of spf1- or ste24-null mutants. Mutations in PIO3 (unidentified) cause a weaker Pio phenotype, enhanced by a null mutation in BMH1, one of two yeast 14-3-3 proteins.

• Authors: Donald J Tipper, Carol A Harley
• Journal: Molecular biology of the cell (Mol Biol Cell) Vol. 13 Issue 4 Pg. 1158-74 (Apr 2002) ISSN: 1059-1524 [Print] United States
• PMID: 11950929 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• DNA-Binding Proteins
• Fungal Proteins
• Membrane Proteins
• Mutagens
• Plant Proteins
• Proteins
• Recombinant Fusion Proteins
• SPF1 protein, plant
• Saccharomyces cerevisiae Proteins
• Ethyl Methanesulfonate
• UBE2L3 protein, human
• Ubiquitin-Conjugating Enzymes
• Glycoside Hydrolases
• beta-Galactosidase
• beta-Fructofuranosidase
• Metalloendopeptidases
• STE24 protein, S cerevisiae
• beta-Lactamases
• Adenosine Triphosphatases
• Ligases

Topics

• Adenosine Triphosphatases (metabolism)
• Cell Membrane (metabolism)
• DNA-Binding Proteins (metabolism)
• Ethyl Methanesulfonate (pharmacology)
• Fungal Proteins (metabolism)
• Gene Library
• Genes, Reporter
• Genetic Complementation Test
• Genetic Vectors
• Glycoside Hydrolases (metabolism)
• Ligases (metabolism)
• Membrane Proteins (metabolism)
• Metalloendopeptidases (metabolism)
• Models, Biological
• Mutagenesis
• Mutagens (pharmacology)
• Mutation
• Phenotype
• Plant Proteins (metabolism)
• Precipitin Tests
• Protein Binding
• Protein Conformation
• Protein Structure, Tertiary
• Proteins (metabolism)
• Recombinant Fusion Proteins (metabolism)
• Saccharomyces cerevisiae (metabolism)
• Saccharomyces cerevisiae Proteins
• Time Factors
• Ubiquitin-Conjugating Enzymes
• beta-Fructofuranosidase
• beta-Galactosidase (metabolism)
• beta-Lactamases (metabolism)