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Mol Cell Biol

Title:		Farnesyl cysteine C-terminal methyltransferase activity is dependent upon the STE14 gene product in Saccharomyces cerevisiae
Author(s):		Hrycyna CA; Clarke S;
Address:		"Department of Chemistry and Biochemistry, University of California, Los Angeles 90024-1569"
Journal Title:		Mol Cell Biol
Year:		1990
Volume:		10
Issue:		10
Page Number:		5071 - 5076
DOI:		10.1128/mcb.10.10.5071-5076.1990
ISSN/ISBN:		0270-7306 (Print) 1098-5549 (Electronic) 0270-7306 (Linking)
Abstract:		"Membrane extracts of sterile Saccharomyces cerevisiae strains containing the a-specific ste14 mutation lack a farnesyl cysteine C-terminal carboxyl methyltransferase activity that is present in wild-type a and alpha cells. Other a-specific sterile strains with ste6 and ste16 mutations also have wild-type levels of the farnesyl cysteine carboxyl methyltransferase activity. This enzyme activity, detected by using a synthetic peptide sequence based on the C-terminus of a ras protein, may be responsible not only for the essential methylation of the farnesyl cysteine residue of a mating factor, but also for the methylation of yeast RAS1 and RAS2 proteins and possibly other polypeptides with similar C-terminal structures. We demonstrate that the farnesylation of the cysteine residue in the peptide is required for the methyltransferase activity, suggesting that methyl esterification follows the lipidation reaction in the cell. To show that the loss of methyltransferase activity is a direct result of the ste14 mutation, we transformed ste14 mutant cells with a plasmid complementing the mating defect of this strain and found that active enzyme was produced. Finally, we demonstrated that a similar transformation of cells possessing the wild-type STE14 gene resulted in sixfold overproduction of the enzyme. Although more complicated possibilities cannot be ruled out, these results suggest that STE14 is a candidate for the structural gene for a methyltransferase involved in the formation of isoprenylated cysteine alpha-methyl ester C-terminal structures"
Keywords:		"Amino Acid Sequence Cell Membrane/metabolism *Genes, Fungal Genetic Complementation Test Mating Factor Methyltransferases/*metabolism Molecular Sequence Data Peptides/metabolism Protein Methyltransferases/*metabolism Protein Processing, Post-Translational;"
Notes:		"MedlineHrycyna, C A Clarke, S eng GM-26020/GM/NIGMS NIH HHS/ Research Support, U.S. Gov't, P.H.S. 1990/10/01 Mol Cell Biol. 1990 Oct; 10(10):5071-6. doi: 10.1128/mcb.10.10.5071-5076.1990"