Afr1p regulates the Saccharomyces cerevisiae α-factor receptor by a mechanism that is distinct from receptor phosphorylation and endocytosis

Colleen Davis, Peter H Dube, James B. Konopka

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

The α-factor pheromone receptor activates a G protein signaling pathway that induces the conjugation of the yeast Saccharomyces cerevisiae. Our previous studies identified AFR1 as a gene that regulates this signaling pathway became overexpression of AFR1 promoted resistance to α-factor. AFR1 also showed an interesting genetic relationship with the α-factor receptor gene, STE2, suggesting that the receptor is regulated by Afr1p. To investigate the mechanism of this regulation, we tested AFR1 for a role in the two processes that are known to regulate receptor signaling: phosphorylation and down-regulation of ligand-bound receptors by endocytosis. AFR1 overexpression diminished signaling in a strain that lacks the C- terminal phosphorylation sites of the receptor, indicating that AFR1 acts independently of phosphorylation. The effects of AFR1 overexpression were weaker in strains that were defective in receptor endocytosis. However, AFR1 overexpression did not detectably influence receptor endocytosis or the stability of the receptor protein. Instead, gene dosage studies showed that the effects of AFR1 overexpression on signaling were inversely proportional to the number of receptors. These results indicate that AFR1 acts independently of endocytosis, and that the weaker effects of AFR1 in strains that are defective in receptor endocytosis were probably an indirect consequence of their increased receptor number caused by the failure of receptors to undergo ligand-stimulated endocytosis. Analysis of the ligand binding properties of the receptor showed that AFR1 overexpression did not alter the number of cell-surface receptors or the affinity for α-factor. Thus, Afr1p prevents α-factor receptors from activating G protein signaling by a mechanism that is distinct from other known pathways.

Original languageEnglish (US)
Pages (from-to)625-635
Number of pages11
JournalGenetics
Volume148
Issue number2
StatePublished - Feb 1998
Externally publishedYes

Fingerprint

Endocytosis
Saccharomyces cerevisiae
Phosphorylation
Ligands
GTP-Binding Proteins
Pheromone Receptors
Gene Dosage
R Factors
Protein Stability
Cell Surface Receptors
Genes
Down-Regulation
Yeasts

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

Cite this

Afr1p regulates the Saccharomyces cerevisiae α-factor receptor by a mechanism that is distinct from receptor phosphorylation and endocytosis. / Davis, Colleen; Dube, Peter H; Konopka, James B.

In: Genetics, Vol. 148, No. 2, 02.1998, p. 625-635.

Research output: Contribution to journalArticle

@article{6dcfe6cfdf8d4892b0e7297031d949e7,
title = "Afr1p regulates the Saccharomyces cerevisiae α-factor receptor by a mechanism that is distinct from receptor phosphorylation and endocytosis",
abstract = "The α-factor pheromone receptor activates a G protein signaling pathway that induces the conjugation of the yeast Saccharomyces cerevisiae. Our previous studies identified AFR1 as a gene that regulates this signaling pathway became overexpression of AFR1 promoted resistance to α-factor. AFR1 also showed an interesting genetic relationship with the α-factor receptor gene, STE2, suggesting that the receptor is regulated by Afr1p. To investigate the mechanism of this regulation, we tested AFR1 for a role in the two processes that are known to regulate receptor signaling: phosphorylation and down-regulation of ligand-bound receptors by endocytosis. AFR1 overexpression diminished signaling in a strain that lacks the C- terminal phosphorylation sites of the receptor, indicating that AFR1 acts independently of phosphorylation. The effects of AFR1 overexpression were weaker in strains that were defective in receptor endocytosis. However, AFR1 overexpression did not detectably influence receptor endocytosis or the stability of the receptor protein. Instead, gene dosage studies showed that the effects of AFR1 overexpression on signaling were inversely proportional to the number of receptors. These results indicate that AFR1 acts independently of endocytosis, and that the weaker effects of AFR1 in strains that are defective in receptor endocytosis were probably an indirect consequence of their increased receptor number caused by the failure of receptors to undergo ligand-stimulated endocytosis. Analysis of the ligand binding properties of the receptor showed that AFR1 overexpression did not alter the number of cell-surface receptors or the affinity for α-factor. Thus, Afr1p prevents α-factor receptors from activating G protein signaling by a mechanism that is distinct from other known pathways.",
author = "Colleen Davis and Dube, {Peter H} and Konopka, {James B.}",
year = "1998",
month = "2",
language = "English (US)",
volume = "148",
pages = "625--635",
journal = "Genetics",
issn = "0016-6731",
publisher = "Genetics Society of America",
number = "2",

}

TY - JOUR

T1 - Afr1p regulates the Saccharomyces cerevisiae α-factor receptor by a mechanism that is distinct from receptor phosphorylation and endocytosis

AU - Davis, Colleen

AU - Dube, Peter H

AU - Konopka, James B.

PY - 1998/2

Y1 - 1998/2

N2 - The α-factor pheromone receptor activates a G protein signaling pathway that induces the conjugation of the yeast Saccharomyces cerevisiae. Our previous studies identified AFR1 as a gene that regulates this signaling pathway became overexpression of AFR1 promoted resistance to α-factor. AFR1 also showed an interesting genetic relationship with the α-factor receptor gene, STE2, suggesting that the receptor is regulated by Afr1p. To investigate the mechanism of this regulation, we tested AFR1 for a role in the two processes that are known to regulate receptor signaling: phosphorylation and down-regulation of ligand-bound receptors by endocytosis. AFR1 overexpression diminished signaling in a strain that lacks the C- terminal phosphorylation sites of the receptor, indicating that AFR1 acts independently of phosphorylation. The effects of AFR1 overexpression were weaker in strains that were defective in receptor endocytosis. However, AFR1 overexpression did not detectably influence receptor endocytosis or the stability of the receptor protein. Instead, gene dosage studies showed that the effects of AFR1 overexpression on signaling were inversely proportional to the number of receptors. These results indicate that AFR1 acts independently of endocytosis, and that the weaker effects of AFR1 in strains that are defective in receptor endocytosis were probably an indirect consequence of their increased receptor number caused by the failure of receptors to undergo ligand-stimulated endocytosis. Analysis of the ligand binding properties of the receptor showed that AFR1 overexpression did not alter the number of cell-surface receptors or the affinity for α-factor. Thus, Afr1p prevents α-factor receptors from activating G protein signaling by a mechanism that is distinct from other known pathways.

AB - The α-factor pheromone receptor activates a G protein signaling pathway that induces the conjugation of the yeast Saccharomyces cerevisiae. Our previous studies identified AFR1 as a gene that regulates this signaling pathway became overexpression of AFR1 promoted resistance to α-factor. AFR1 also showed an interesting genetic relationship with the α-factor receptor gene, STE2, suggesting that the receptor is regulated by Afr1p. To investigate the mechanism of this regulation, we tested AFR1 for a role in the two processes that are known to regulate receptor signaling: phosphorylation and down-regulation of ligand-bound receptors by endocytosis. AFR1 overexpression diminished signaling in a strain that lacks the C- terminal phosphorylation sites of the receptor, indicating that AFR1 acts independently of phosphorylation. The effects of AFR1 overexpression were weaker in strains that were defective in receptor endocytosis. However, AFR1 overexpression did not detectably influence receptor endocytosis or the stability of the receptor protein. Instead, gene dosage studies showed that the effects of AFR1 overexpression on signaling were inversely proportional to the number of receptors. These results indicate that AFR1 acts independently of endocytosis, and that the weaker effects of AFR1 in strains that are defective in receptor endocytosis were probably an indirect consequence of their increased receptor number caused by the failure of receptors to undergo ligand-stimulated endocytosis. Analysis of the ligand binding properties of the receptor showed that AFR1 overexpression did not alter the number of cell-surface receptors or the affinity for α-factor. Thus, Afr1p prevents α-factor receptors from activating G protein signaling by a mechanism that is distinct from other known pathways.

UR - http://www.scopus.com/inward/record.url?scp=0031912253&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031912253&partnerID=8YFLogxK

M3 - Article

C2 - 9504911

AN - SCOPUS:0031912253

VL - 148

SP - 625

EP - 635

JO - Genetics

JF - Genetics

SN - 0016-6731

IS - 2

ER -