The RACK1 Ortholog Asc1 Functions as a G-protein β Subunit Coupled to Glucose Responsiveness in Yeast

Zeller, Corinne E.; Parnell, Stephen C.; Dohlman, Henrik G.

doi:10.1074/jbc.m702569200

Cited by 99 publications

(149 citation statements)

References 79 publications

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“…In fact, only two genes-ASC1 and SRN2-fall into this category. ASC1 encodes a core component of the 40S ribosomal subunit, which acts as a guanine nucleotide dissociation inhibitor for Gpa2 (Zeller et al 2007), and its deletion results in longer telomeres (Askree et al 2004). Srn2 is a member of the ESCRT-1 endosomal sorting complex (Kostelansky et al 2007), which targets proteins to endosomes in a ubiquitin-dependent manner.…”

Section: Discussionmentioning

confidence: 99%

A Genomewide Suppressor and Enhancer Analysis of cdc13-1 Reveals Varied Cellular Processes Influencing Telomere Capping in Saccharomyces cerevisiae

Addinall

Downey

et al. 2008

Genetics

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In Saccharomyces cerevisiae, Cdc13 binds telomeric DNA to recruit telomerase and to ''cap'' chromosome ends. In temperature-sensitive cdc13-1 mutants telomeric DNA is degraded and cell-cycle progression is inhibited. To identify novel proteins and pathways that cap telomeres, or that respond to uncapped telomeres, we combined cdc13-1 with the yeast gene deletion collection and used high-throughput spot-test assays to measure growth. We identified 369 gene deletions, in eight different phenotypic classes, that reproducibly demonstrated subtle genetic interactions with the cdc13-1 mutation. As expected, we identified DNA damage checkpoint, nonsense-mediated decay and telomerase components in our screen. However, we also identified genes affecting casein kinase II activity, cell polarity, mRNA degradation, mitochondrial function, phosphate transport, iron transport, protein degradation, and other functions. We also identified a number of genes of previously unknown function that we term RTC, for restriction of telomere capping, or MTC, for maintenance of telomere capping. It seems likely that many of the newly identified pathways/ processes that affect growth of budding yeast cdc13-1 mutants will play evolutionarily conserved roles at telomeres. The high-throughput spot-testing approach that we describe is generally applicable and could aid in understanding other aspects of eukaryotic cell biology.

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Section: Discussionmentioning

confidence: 99%

A Genomewide Suppressor and Enhancer Analysis of cdc13-1 Reveals Varied Cellular Processes Influencing Telomere Capping in Saccharomyces cerevisiae

Addinall

Downey

et al. 2008

Genetics

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“…It is unclear whether the G a protein Gpa2 also associates with canonical G b and G c subunits. A recent report suggests that Asc1 functions as the G b subunit for Gpa2 (Zeller et al 2007). Asc1 has the typical 7-WD domain structure of a canonical G b protein, interacts directly with Gpa2 in a guanine nucleotide-dependent manner and inhibits Gpa2 guanine nucleotide exchange activity.…”

Section: Regulation Of the Camp-pka Pathwaymentioning

confidence: 99%

Life in the midst of scarcity: adaptations to nutrient availability in Saccharomyces cerevisiae

et al. 2010

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Cells of all living organisms contain complex signal transduction networks to ensure that a wide range of physiological properties are properly adapted to the environmental conditions. The fundamental concepts and individual building blocks of these signalling networks are generally well-conserved from yeast to man; yet, the central role that growth factors and hormones play in the regulation of signalling cascades in higher eukaryotes is executed by nutrients in yeast. Several nutrient-controlled pathways, which regulate cell growth and proliferation, metabolism and stress resistance, have been defined in yeast. These pathways are integrated into a signalling network, which ensures that yeast cells enter a quiescent, resting phase (G 0 ) to survive periods of nutrient scarceness and that they rapidly resume growth and cell proliferation when nutrient conditions become favourable again. A series of well-conserved nutrient-sensory protein kinases perform key roles in this signalling network: i.e. Snf1, PKA, Tor1 and Tor2, Sch9 and Pho85-Pho80. In this review, we provide a comprehensive overview on the current understanding of the signalling processes mediated via these kinases with a particular focus on how these individual pathways converge to signalling networks that ultimately ensure the dynamic translation of extracellular nutrient signals into appropriate physiological responses.

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“…Asc1p's involvement in cellular signal transduction prompted us to investigate Asc1p-sensitive protein phosphorylation beyond its own phosphorylation. Previous studies reported that the absence of Asc1p leads to increased phosphorylation of the MAPKs Kss1p and Slt2p, which control filamentous growth, mating, and cell wall integrity (2,29). In the present study, we additionally analyzed the phosphorylation of the MAPK of the high-osmolarity response pathway, Hog1p, by using an antibody specific for this protein phosphorylated at residues T174 and/or Y176 by its upstream mitogen-activated protein kinase kinase (MAP2K), Pbs2p.…”

Section: Figurementioning

confidence: 99%

Asc1p/RACK1 Connects Ribosomes to Eukaryotic Phosphosignaling

Schmitt

Smolinski

Neumann

et al. 2017

Molecular and Cellular Biology

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WD40 repeat proteins fold into characteristic ␤-propeller structures and control signaling circuits during cellular adaptation processes within eukaryotes. The RACK1 protein of Saccharomyces cerevisiae, Asc1p, consists exclusively of a single sevenbladed ␤-propeller that operates from the ribosomal base at the head region of the 40S subunit. Here we show that the R38D K40E ribosomal binding-compromised variant (Asc1DEp) is severely destabilized through mutation of phosphosite T143 to a dephosphorylation-mimicking alanine, probably through proteasomal degradation, leading to asc1 Ϫ phenotypes. Phosphosite Y250 contributes to resistance to translational inhibitors but does not influence Asc1DEp stability. Beyond its own phosphorylation at T143, Y250, and other sites, Asc1p heavily influences the phosphorylation of as many as 90 proteins at 120 sites. Many of these proteins are regulators of fundamental processes ranging from mRNA translation to protein transport and turnover, cytoskeleton organization, and cellular signaling. Our data expose Asc1p/ RACK1 as a key factor in phosphosignaling and manifest it as a control point at the head of the ribosomal 40S subunit itself regulated through posttranslational modification.

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The RACK1 Ortholog Asc1 Functions as a G-protein β Subunit Coupled to Glucose Responsiveness in Yeast

Cited by 99 publications

References 79 publications

A Genomewide Suppressor and Enhancer Analysis of cdc13-1 Reveals Varied Cellular Processes Influencing Telomere Capping in Saccharomyces cerevisiae

A Genomewide Suppressor and Enhancer Analysis of cdc13-1 Reveals Varied Cellular Processes Influencing Telomere Capping in Saccharomyces cerevisiae

Life in the midst of scarcity: adaptations to nutrient availability in Saccharomyces cerevisiae

Asc1p/RACK1 Connects Ribosomes to Eukaryotic Phosphosignaling

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