Down regulation of the α-factor pheromone receptor in S. cerevisiae

Jenness, Duane D.; Spatrick, Phyllis

doi:10.1016/0092-8674(86)90655-0

Cited by 168 publications

(162 citation statements)

References 33 publications

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“…The conformational change necessary for endocytosis does not appear to require G-protein function (5,21,50). Endocytosis requires the C-terminal domain of the receptor (35,38) and is not blocked by mutations in the third intracellular loop (38,48).…”

Section: Fig 4 Effects Of Mutations and Antagonist On The Cleavage mentioning

confidence: 99%

“…Certain mutations affecting the third intracellular loop of the receptor severely block its ability to couple with the G protein and to generate an intracellular signal (48). Other ␣-factor responses include receptor endocytosis (10,21,38) and phosphorylation (9, 34), mating-partner selection (19,42), and the promotion of changes in cellular morphology (23). In this report, we show that ␣-factor-induced conformational changes in the receptor result in enhanced accessibility of the * Corresponding author.…”

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confidence: 99%

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Agonist-Specific Conformational Changes in the Yeast α-Factor Pheromone Receptor

Bukusoglu

Jenness

1996

Molecular and Cellular Biology

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The yeast ␣-factor pheromone receptor is a member of the G-protein-coupled receptor family. Limited trypsin digestion of yeast membranes was used to investigate ligand-induced conformational changes in this receptor. The agonist, ␣-factor, accelerated cleavage in the third intracellular loop, whereas the antagonist, desTrp1,Ala3-␣-factor, reduced the cleavage rate. Thus, the enhanced accessibility of the third intracellular loop is specific to the agonist. ␣-Factor inhibited cleavage weakly at a second site near the cytoplasmic terminus of the seventh transmembrane helix, whereas the antagonist showed a stronger inhibition of cleavage at this site and at another site in the C-terminal domain of the receptor. The ␣-factor-induced conformational changes appeared to be inherent properties of the receptor, as they were retained in G-protein-deficient mutants. Moreover, a mutant receptor (ste2-L236H) that affects the third loop and is defective for G-protein coupling retained the ability to undergo the agonist-induced conformational changes. These results are consistent with a model in which G-protein activation is limited by the availability of specific contacts between the G protein and the third intracellular loop of the receptor. The antagonist appears to promote a distinct conformational state that differs from either the unoccupied or the agonist-occupied state.Receptors coupled to heterotrimeric GTP-binding proteins (G proteins) contain seven transmembrane helices and control cellular responses to a variety of stimuli, including hormones, neurotransmitters, light, and odorants (2, 13, 46). It is widely believed that the conformational changes induced by agonist binding permit these receptors to associate productively with G proteins, thus resulting in the exchange of GDP for GTP in the G ␣ subunit. Three lines of evidence suggest that the third intracellular loop of the receptor provides at least some of the intermolecular contacts that promote guanine nucleotide exchange: (i) work with chimeric receptors indicates that the third intracellular loop influences the specificity of G-protein interactions (13); (ii) mutations in the third intracellular loop (2,11,46,48) block coupling of receptors to their respective G proteins; and (iii) synthetic peptides that comprise the third loop bind G proteins in vitro, thereby stimulating nucleotide exchange and blocking the association of the G protein with the receptor (47). It has been proposed that structural constraints in receptors prevent the third intracellular loop from contacting the G protein when agonists are absent and that these structural constraints are relieved when the receptor assumes an agonist-activated conformation (36). However, there is as yet no direct evidence which demonstrates that increased exposure of the third intracellular loop is a specific consequence of agonist binding.The ability of ligands to promote changes in protein conformation has been largely pioneered by studying hemoglobin and allosteric enzymes (1, 37, 41). In general, alloster...

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Section: Fig 4 Effects Of Mutations and Antagonist On The Cleavage mentioning

confidence: 99%

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confidence: 99%

Agonist-Specific Conformational Changes in the Yeast α-Factor Pheromone Receptor

Bukusoglu

Jenness

1996

Molecular and Cellular Biology

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“…Further, this outcome establishes that Ste11 is subject to different modes of regulation in the two pathways. This phenomenon occurs through several desensitization or adaptation mechanisms that impinge on different components of the signaling pathway (37)(38)(39)(40)(41)(42)(43)(44)(45). The feedback and ubiquitindependent degradation of Ste11 could be an additional mechanism that contributes to desensitization.…”

Section: Ste11 Protein Stability Is Not Affected By Hyperosmotic Stressmentioning

confidence: 99%

Pheromone induction promotes Ste11 degradation through a MAPK feedback and ubiquitin-dependent mechanism

Esch

Errede

2002

Proc. Natl. Acad. Sci. U.S.A.

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Ste11 is the mitogen-activated protein kinase (MAPK) kinase kinase in the MAPK cascades that mediate mating, high osmolarity glycerol, and filamentous growth responses in Saccharomyces cerevisiae. We show stimulation of the mating pathway by pheromone promotes an accelerated turnover of Ste11 through a MAPK feedback and ubiquitin-dependent mechanism. This degradation is pathway specific, because Ste11 is stable during activation of the high osmolarity glycerol pathway. Because the steady-state amount of Ste11 does not change significantly during pheromone induction, we infer that maintenance of MAPK activation involves repeated cycles in which naïve Ste11 is activated and then targeted for degradation. This model predicts that elimination of active Ste11 would rapidly curtail MAPK activation upon attenuation of the upstream signal. This prediction is confirmed by the finding that blocking ubiquitin-dependent Ste11 degradation during pheromone induction abolishes the characteristic attenuation profile for MAPK activation.

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“…Secretion is essential for this process because -factor is secreted and the a-factor exporter and both pheromone receptors must be 1908 Journal of Cell Science 123 (11) continually delivered to polarized sites on the cell surface to replace proteins internalized by endocytosis (Chen and Davis, 2000;Jenness and Spatrick, 1986;Kolling and Hollenberg, 1994). Matingpair assembly increases the efficiency of pheromone signaling by concentrating pheromone release sites and pheromone receptors on opposite sides of the contact site to create a structure analogous to a neuronal synapse.…”

Section: Secretion Pheromone Signaling and Cell Fusionmentioning

confidence: 99%

Secretion is required for late events in the cell-fusion pathway of mating yeast

Grote

2010

Journal of Cell Science

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SummarySecretory vesicles accumulate adjacent to the contact site between the two cells of a yeast mating pair before they fuse, but there is no direct evidence that secretion is required to complete fusion. In this study, temperature-sensitive secretion (sec ts ) mutants were used to investigate the role of secretion in yeast cell fusion. Cell fusion arrested less than 5 minutes after inhibiting secretion. This rapid fusion arrest was not an indirect consequence of reduced mating pheromone signaling, mating-pair assembly or actin polarity. Furthermore, secretion was required to complete cell fusion when it was transiently inhibited by addition and removal of the lipophilic styryl dye, FM4-64. These results indicate that ongoing secretion is required for late events in the cell-fusion pathway, which include plasma-membrane fusion and the completion of cell-wall remodeling, and they demonstrate a just-in-time delivery mechanism for the cell-fusion machinery.

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Down regulation of the α-factor pheromone receptor in S. cerevisiae

Cited by 168 publications

References 33 publications

Agonist-Specific Conformational Changes in the Yeast α-Factor Pheromone Receptor

Agonist-Specific Conformational Changes in the Yeast α-Factor Pheromone Receptor

Pheromone induction promotes Ste11 degradation through a MAPK feedback and ubiquitin-dependent mechanism

Secretion is required for late events in the cell-fusion pathway of mating yeast

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