Overexpression of RPI1, a novel inhibitor of the yeast Ras-cyclic AMP pathway, down-regulates normal but not mutationally activated ras function

Kim, J. H., Powers, S. (August 1991) Overexpression of RPI1, a novel inhibitor of the yeast Ras-cyclic AMP pathway, down-regulates normal but not mutationally activated ras function. Molecular and Cellular Biology, 11 (8). pp. 3894-904. ISSN 0270-7306

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URL: http://www.ncbi.nlm.nih.gov/pubmed/1649384

Abstract

A high-copy-number plasmid genomic library was screened for genes that when overexpressed down-regulate Ras protein activity in Saccharomyces cerevisiae. We report on the structure and characterization of one such gene, RPI1, which potentially encodes a novel 46-kDa negative regulator of the Ras-cyclic AMP pathway. Three lines of evidence suggest that the RPI1 gene product operates upstream to negatively regulate the activity of normal but not mutationally activated Ras proteins: (i) overexpressed RPI1 lowers cyclic AMP levels in wild-type yeast cells but not in yeast cells carrying the RAS2Val-19 mutation, (ii) overexpressed RPI1 suppresses the heat shock sensitivity phenotype induced by overexpression of normal RAS2 but does not suppress the same phenotype induced by RAS2Val-19, and (iii) disruption of RPI1 results in a heat shock sensitivity phenotype which can be suppressed by mutations that lower normal Ras activity. Thus, RPI1 appears to encode an inhibitor of Ras activity that shares a common feature with Ras GTPase-activating proteins in that it fails to down-regulate activated RAS2Val-19 function. We present evidence that the down-regulatory effect of RPI1 requires the presence of one of the two Ras GTPase activators, IRA1 and IRA2.

Item Type: Paper
Uncontrolled Keywords: Amino Acid Sequence Base Sequence Cyclic AMP/*metabolism Fungal Proteins/antagonists & inhibitors/*genetics/*metabolism GTP-Binding Proteins/metabolism Gene Expression Regulation, Fungal Genes, Fungal Genomic Library Genotype Molecular Sequence Data Oligonucleotide Probes Plasmids *Repressor Proteins Restriction Mapping Saccharomyces cerevisiae/*genetics/metabolism *Saccharomyces cerevisiae Proteins Suppression, Genetic *ras Proteins
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > transcription factor > Cyclic AMP
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > G protein
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > G protein > Ras
organism description > yeast
CSHL Authors:
Communities: CSHL labs > Powers lab
Depositing User: Matt Covey
Date: August 1991
Date Deposited: 25 Feb 2014 21:54
Last Modified: 25 Feb 2014 21:54
PMCID: PMC361179
Related URLs:
URI: http://repository.cshl.edu/id/eprint/29515

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