Regulated arrest of cell proliferation mediated by yeast prt1 mutations

Hanic-Joyce, Pamela J.; Johnston, Gerald C.; Singer, Richard A.

doi:10.1016/0014-4827(87)90100-5

Cited by 64 publications

(60 citation statements)

References 23 publications

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“…The protein product of RPG1 was not characterized then, but analysis of a temperature-sensitive rpg1-1 allele demonstrated that cells shifted to nonpermissive temperature arrest in the G 1 phase (34). A similar phenotype was observed for mutant alleles of PRT1 (encoding p90) (35) and TIF34 (encoding p39) (29). These data suggest that a properly functioning eIF3, presumably providing efficient translation initiation and protein synthesis, is required for progression through START and the cell cycle (36,37).…”

Section: Table III Two Hybrid Interactions Within Yeast Eif3 Subunitssupporting

confidence: 65%

A 110-Kilodalton Subunit of Translation Initiation Factor eIF3 and an Associated 135-kilodalton Protein Are Encoded by theSaccharomyces cerevisiae TIF32 and TIF31Genes

Vornlocher¹,

Hanachi

Ribeiro³

et al. 1999

Journal of Biological Chemistry

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Translation initiation factor eIF3 is a multisubunit protein complex required for initiation of protein biosynthesis in eukaryotic cells. The complex promotes ribosome dissociation, the binding of the initiator methionyl-tRNA to the 40 S ribosomal subunit, and mRNA recruitment to the ribosome. In the yeast Saccharomyces cerevisiae eIF3 comprises up to 8 subunits. Using partial peptide sequences generated from proteins in purified eIF3, we cloned the TIF31 and TIF32 genes encoding 135-(p135) and 110-kDa (p110) proteins. Deletion/ disruption of TIF31 results in no change in growth rate, whereas deletion of TIF32 is lethal. Depletion of p110 causes a severe reduction in cell growth and protein synthesis rates as well as runoff of ribosomes from polysomes, indicative of inhibition of the initiation phase. In addition, p110 depletion leads to p90 co-depletion, whereas other eIF3 subunit levels are not affected. Immunoprecipitation or nickel affinity chromatography from strains expressing (His) 6 -tagged p110 or p33 results in the co-purification of the well characterized p39 and p90 subunits of eIF3 as well as p110 and p33. This establishes p110 as an authentic subunit of eIF3. In similar experiments, p135 and other eIF3 subunits sometimes, but not always, co-purify, making assignment of p135 as an eIF3 subunit uncertain. Far Western blotting and two-hybrid analyses detect a direct interaction of p110 with p90, p135 with p33, and p33 with eIF4B. Our results, together with those from other laboratories, complete the cloning and characterization of all of the yeast eIF3 subunits.The initiation phase of protein synthesis in eukaryotes is promoted by 10 or more proteins called eukaryotic initiation factors (eIFs) 1 (for reviews, see Refs. 1 and 2). The largest and most complex of these, eIF3, is a 600-kDa factor with 8 or more subunit proteins. Based on in vitro biochemical studies of the mammalian system, eIF3 is implicated in a large number of reactions in the initiation pathway. eIF3 alone among the initiation factors binds stably to 40 S ribosomal subunits (3). The factor promotes the dissociation of 80 S ribosomes into 40 S and 60 S subunits, affects the stability of the ternary complex comprising methionyl-tRNA i ⅐eIF2⅐GTP in the absence of ribosomes but in the presence of mRNA, and stabilizes methionyltRNA i binding to 40 S subunits (1). It also is absolutely required for mRNA binding to ribosomes, where eIF3 already bound to the 40 S ribosome interacts with a region of eIF4G, a component of the mRNA m 7 G-cap binding complex, eIF4F (4). Thus eIF3 acts as a bridge between the 40 S ribosome and the mRNA⅐eIF4F complex. It is apparent that eIF3 plays a central role in initiation by interacting with numerous other translational components.To better understand the function of eIF3, the cDNAs encoding 11 human eIF3 subunits have been cloned and characterized: p170 (5), p116 (6), p110 (7), p66 (8), p48 (9), p47 (8), p44 (10), p40 (8), p36 (7), p35 (10), and p28.2 Knowledge of the primary sequences of these proteins sheds...

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Section: Table III Two Hybrid Interactions Within Yeast Eif3 Subunitssupporting

confidence: 65%

A 110-Kilodalton Subunit of Translation Initiation Factor eIF3 and an Associated 135-kilodalton Protein Are Encoded by theSaccharomyces cerevisiae TIF32 and TIF31Genes

Vornlocher¹,

Hanachi

Ribeiro³

et al. 1999

Journal of Biological Chemistry

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“…We propose that the observed cell cycle arrest in cdc123 mutants is a consequence of reduced translation initiation rates, because the G1/S transition is especially sensitive to defects in protein synthesis (39). Indeed, several translation initiation factors were initially identified as cell division cycle mutants in yeast, for example the cap-binding protein eIF4E encoded by CDC33 (40) or the eIF3 subunit Prt1 encoded by CDC63 (41).…”

Section: Discussionmentioning

confidence: 99%

Translation Initiation Requires Cell Division Cycle 123 (Cdc123) to Facilitate Biogenesis of the Eukaryotic Initiation Factor 2 (eIF2)

Perzlmaier

Richter

Seufert

2013

Journal of Biological Chemistry

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Background:The eukaryotic translation initiation factor 2 (eIF2) is a heterotrimeric G-protein.Results: Cdc123, a conserved cell proliferation protein, binds the unassembled eIF2␥ subunit to promote eIF2 complex formation. Conclusion: Cdc123 is a specific eIF2 assembly factor indispensable for the onset of protein synthesis. Significance: This study describes a novel step in the eukaryotic translation initiation pathway.

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“…(a) Western blots of extracts from mycer and BALB 3T3 control cells stimulated with estrogen reveal increased expression of eIF4E, eIF2a and cyclin D1 in response to activation of c-myc function by estradiol addition (data re-plotted: (Rosenwald, 1996;Rosenwald et al, 1993a,b)). (b) Protein synthesis increased in mycer cells 16 h before any increase in DNA synthesis was observed (cdc63) are speci®c regulators of START (Hanic-Joyce et al, 1987). The cdc63 version of prt-1 cells are mutant in the Z component of the eukaryotic translation initiation complex 3 (eIF3Z).…”

Section: Functions Of C-myc In Growth Controlmentioning

confidence: 99%

“…The eIF3 complex acts at nearly all steps of translation initiation to stabilize interactions between all of the initiation factors. Yeast mutations in one of its components, eIF3Z (cdc63), can exhibit a true START arrest (Hanic-Joyce, 1985;Hanic-Joyce et al, 1987). This mutation is of particular interest since cdc63 cells continue to grow in size at the restrictive temperature although protein synthesis is generally decreased.…”

Section: Elements Of Growth Controlmentioning

confidence: 99%