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Updated: Aug 11, 2026
04:36
Assay for Adhesion and Agar Invasion in S. cerevisiae
Published on: November 8, 2006
Fatty acylation is important but not essential for Saccharomyces cerevisiae RAS function
Molecular and Cellular Biology
|July 1, 1987
Summary
Fatty acylation is crucial for yeast RAS2 protein localization to membranes, impacting its function. However, this modification isn't strictly essential for RAS2 protein activity.
Area of Science:
- Molecular Biology
- Yeast Genetics
- Protein Modification
Background:
- RAS1 and RAS2 proteins in Saccharomyces cerevisiae are homologous to mammalian ras oncogene proteins.
- Fatty acylation, specifically palmitoylation, is a post-translational modification implicated in protein function and localization.
Purpose of the Study:
- To investigate the role of fatty acylation in the maturation and function of yeast RAS2 protein.
- To determine if palmitoylation at the carboxyl terminus is essential for RAS2 protein localization and activity.
Main Methods:
- Site-directed mutagenesis was used to create mutations at the putative palmitoylation site (Cys-318 and Cys-319) of the RAS2 gene.
- Mutant RAS2 alleles were substituted into the yeast chromosome.
- Protein acylation, membrane localization, and functional phenotypes (growth on nonfermentable carbon sources, complementation of ras1 mutants) were assessed.
Main Results:
- Mutations preventing palmitoylation (Cys-318 to opal, Cys-319 to Ser) abolished RAS2 protein acylation and membrane localization.
- These mutations resulted in a Ras2- phenotype, impairing growth on nonfermentable carbon sources and complementation of ras1 mutants.
- Overexpression of the non-acylated Ras2Ser-319 protein partially restored a Ras+ phenotype without membrane association.
Conclusions:
- Fatty acylation is important for the proper membrane localization of RAS2 protein, which is necessary for its full activity.
- While essential for localization, the fatty acyl group itself is not an absolute requirement for RAS2 protein function, as demonstrated by overexpression studies.
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