scholarly journals Modification of yeast ribosomal proteins. Phosphorylation

1978 ◽  
Vol 175 (1) ◽  
pp. 213-219 ◽  
Author(s):  
T Kruiswijk ◽  
J T de Hey ◽  
R J Planta
Keyword(s):  
Ribosomal Proteins ◽  
Ribosomal Subunit ◽  
Electrophoretic Analysis ◽  
Ribosome Assembly ◽  
Two Dimensional ◽  
Protein Species ◽  
Phosphorylated Protein ◽  
40S Ribosomal Subunit ◽  
Phosphate Groups

Two-dimensional polyacrylamide-gel electrophoretic analysis of yeast ribosomal proteins labelled in vivo with 32PO43- revealed that the proteins S2 and S10 of the 40S ribosomal subunit, and the proteins L9, L30, L44 and L45 of the 60S ribosomal subunit, are phosphorylated in vivo. Most of the phosphate groups appeared to be linked to serine residues. Teh number of phosphate groups per molecule of phosphorylated protein species ranged from 0.01 to 0.79. Since most of the phosphorylated ribosomal proteins appear to associate with the pre-ribosomal particles at a very late stage of ribosome assembly, phosphorylation is more likely to play a role in the functioning of the ribosome than in its assembly.

scholarly journals Modification of yeast ribosomal proteins. Methylation

1978 ◽  
Vol 175 (1) ◽  
pp. 221-225 ◽  
Author(s):  
T Kruiswijk ◽  
A Kunst ◽  
R J Planta ◽  
W H Mager
Keyword(s):  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Electrophoretic Analysis ◽  
Polyacrylamide Gel ◽  
Methyl Groups ◽  
Two Dimensional ◽  
Protein Species ◽  
Methyl Group

Two-dimensional polyacrylamide-gel electrophoretic analysis of yeast ribosomal proteins uniformly labelled in vivo with [methyl-3H]methionine and [1-14C]methionine revealed that four ribosomal proteins are methylated, i.e. proteins S31, S32, L15 and L41. Lysine and arginine appear to be the predominant acceptors of the methyl groups. The degree of methylation ranges from 0.09 to 0.20 methyl group per modified ribosomal protein species.

scholarly journals Mitochondrial ribosome assembly in Neurospora. Two-dimensional gel electrophoretic analysis of mitochondrial ribosomal proteins.

1979 ◽  
Vol 82 (1) ◽  
pp. 17-31 ◽  
Author(s):  
A M Lambowitz ◽  
R J LaPolla ◽  
R A Collins
Keyword(s):  
Gel Electrophoresis ◽  
Ribosomal Proteins ◽  
Ribosomal Subunit ◽  
Protein S ◽  
Electrophoretic Analysis ◽  
Small Subunit ◽  
Ribosome Assembly ◽  
Two Dimensional ◽  
Two Dimensional Gel Electrophoresis ◽  
Mitochondrial Ribosome

Recent results with Neurospora crassa show that one protein (S-5, mol wt 52,000) associated with the mitochondrial (mit) small ribosomal subunit is translated within the mitochondria (Lambowitz et al. 1976. J. Mol. Biol. 107:223-253). In the present work, Neurospora mit ribosomal proteins were analyzed by two-dimensional gel electrophoresis using a modification of the gel system of Mets and Bogorad. The results show that S-5 is present in near stoichiometric concentrations in high salt (0.5 MKCl)-washed mit small subunits from wild-type strains. S-5 is among the most basic mit ribosomal proteins (pI greater than 10) and has a high affinity for RNA under the conditions of the urea-containing gel buffers. The role of S-5 in mit ribosome assembly was investigated by an indirect method, making use of chloramphenicol to specifically inhibit mit protein synthesis. Chloramphenicol was found to rapidly inhibit the assembly of mit small subunits leading to the formation of CAP-30S particles which sediment slightly behind mature small subunits (LaPolla and Lambowitz. 1977. J. Mol. 116: 189-205). Two-dimensional gel analysis shows that the more slowly sedimentaing CAP-30S particles are deficient in S-5 and in several other proteins, whereas these proteins are present in normal concentrations in mature small subunits from the same cells. Because S-5 is the only mit ribosomal protein whose synthesis is directly inhibited by chloramphenicol, the results tentatively suggest that S-5 plays a role in the assembly of mit small subunits. In addition, the results are consistent with the idea that S-5 stabilizes the binding of several other mit small subunit proteins. Two-dimensional gel electrophoresis was used to examine mit ribosomal proteins from [poky] and six additional extra-nuclear mutants with defects in the assembly of mit small subunits. The electrophoretic mobility of S-5 is not detectably altered in any of the mutants. However, [poky] mit small subunits are deficient in S-5 and also contain several other proteins in abnormally low or high concentrations. These and other results are consistent with a defect in a mit ribosomal constituent in [poky].

scholarly journals Identification of Novel Escherichia coli Ribosome-Associated Proteins Using Isobaric Tags and Multidimensional Protein Identification Techniques

2007 ◽  
Vol 189 (9) ◽  
pp. 3434-3444 ◽  
Author(s):  
M. Jiang ◽  
S. M. Sullivan ◽  
A. K. Walker ◽  
J. R. Strahler ◽  
P. C. Andrews ◽  
...  
Keyword(s):  
Ribosomal Proteins ◽  
Protein Identification ◽  
Ribosomal Subunit ◽  
Ribosome Assembly ◽  
Absolute Quantitation ◽  
Proteomic Approach ◽  
Assembly Factors ◽  
Associated Proteins ◽  
Isobaric Tags

ABSTRACT Biogenesis of the large ribosomal subunit requires the coordinate assembly of two rRNAs and 33 ribosomal proteins. In vivo, additional ribosome assembly factors, such as helicases, GTPases, pseudouridine synthetases, and methyltransferases, are also critical for ribosome assembly. To identify novel ribosome-associated proteins, we used a proteomic approach (isotope tagging for relative and absolute quantitation) that allows for semiquantitation of proteins from complex protein mixtures. Ribosomal subunits were separated by sucrose density centrifugation, and the relevant fractions were pooled and analyzed. The utility and reproducibility of the technique were validated via a double duplex labeling method. Next, we examined proteins from 30S, 50S, and translating ribosomes isolated at both 16°C and 37°C. We show that the use of isobaric tags to quantify proteins from these particles is an excellent predictor of the particles with which the proteins associate. Moreover, in addition to bona fide ribosomal proteins, additional proteins that comigrated with different ribosomal particles were detected, including both known ribosomal assembly factors and unknown proteins. The ribosome association of several of these proteins, as well as others predicted to be associated with ribosomes, was verified by immunoblotting. Curiously, deletion mutants for the majority of these ribosome-associated proteins had little effect on cell growth or on the polyribosome profiles.

scholarly journals Depletion of yeast ribosomal proteins L16 or rp59 disrupts ribosome assembly.

1990 ◽  
Vol 111 (6) ◽  
pp. 2261-2274 ◽  
Author(s):  
M Moritz ◽  
A G Paulovich ◽  
Y F Tsay ◽  
J L Woolford
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ribosomal Proteins ◽  
Ribosomal Subunit ◽  
Ribosome Assembly ◽  
Ribosomal Rnas ◽  
Subunit Protein ◽  
40S Ribosomal Subunit ◽  
Ribosomal Subunit Protein ◽  
The Stability

Two strains of Saccharomyces cerevisiae were constructed that are conditional for synthesis of the 60S ribosomal subunit protein, L16, or the 40S ribosomal subunit protein, rp59. These strains were used to determine the effects of depriving cells of either of these ribosomal proteins on ribosome assembly and on the synthesis and stability of other ribosomal proteins and ribosomal RNAs. Termination of synthesis of either protein leads to diminished accumulation of the subunit into which it normally assembles. Depletion of L16 or rp59 has no effect on synthesis of most other ribosomal proteins or ribosomal RNAs. However, most ribosomal proteins and ribosomal RNAs that are components of the same subunit as L16 or rp59 are rapidly degraded upon depletion of L16 or rp59, presumably resulting from abortive assembly of the subunit. Depletion of L16 has no effect on the stability of most components of the 40S subunit. Conversely, termination of synthesis of rp59 has no effect on the stability of most 60S subunit components. The implications of these findings for control of ribosome assembly and the order of assembly of ribosomal proteins into the ribosome are discussed.

scholarly journals The Escherichia coli GTPase CgtAE Is Involved in Late Steps of Large Ribosome Assembly

2006 ◽  
Vol 188 (19) ◽  
pp. 6757-6770 ◽  
Author(s):  
Mengxi Jiang ◽  
Kaustuv Datta ◽  
Angela Walker ◽  
John Strahler ◽  
Pia Bagamasbad ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Large Subunit ◽  
Ribosomal Subunit ◽  
Ribosome Assembly ◽  
Macromolecular Complex ◽  
Large Ribosomal Subunit ◽  
Proteomic Approach ◽  
Temporal Relationships

ABSTRACT The bacterial ribosome is an extremely complicated macromolecular complex the in vivo biogenesis of which is poorly understood. Although several bona fide assembly factors have been identified, their precise functions and temporal relationships are not clearly defined. Here we describe the involvement of an Escherichia coli GTPase, CgtAE, in late steps of large ribosomal subunit biogenesis. CgtAE belongs to the Obg/CgtA GTPase subfamily, whose highly conserved members are predominantly involved in ribosome function. Mutations in CgtAE cause both polysome and rRNA processing defects; small- and large-subunit precursor rRNAs accumulate in a cgtAE mutant. In this study we apply a new semiquantitative proteomic approach to show that CgtAE is required for optimal incorporation of certain late-assembly ribosomal proteins into the large ribosomal subunit. Moreover, we demonstrate the interaction with the 50S ribosomal subunits of specific nonribosomal proteins (including heretofore uncharacterized proteins) and define possible temporal relationships between these proteins and CgtAE. We also show that purified CgtAE associates with purified ribosomal particles in the GTP-bound form. Finally, CgtAE cofractionates with the mature 50S but not with intermediate particles accumulated in other large ribosome assembly mutants.

Ribosomal protein S14 is altered by two-step emetine resistance mutations in Chinese hamster cells

1983 ◽  
Vol 3 (2) ◽  
pp. 190-197
Author(s):  
J J Madjar ◽  
M Frahm ◽  
S McGill ◽  
D J Roufa
Keyword(s):  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Ribosomal Subunit ◽  
Chinese Hamster ◽  
Complementation Group ◽  
Resistance Mutations ◽  
Cho Cell ◽  
Ribosomal Subunits ◽  
40S Ribosomal Subunit ◽  
One Step

Four two-dimensional polyacrylamide gel electrophoresis systems were used to identify 78 Chinese hamster cell ribosomal proteins by the uniform nomenclature based on rat liver ribosomal proteins. The 40S ribosomal subunit protein affected by Chinese hamster ovary (CHO) cell one-step emetine resistance mutations is designated S14 in the standard nomenclature. To seek unambiguous genetic evidence for a cause and effect relationship between CHO cell emetine resistance and mutations in the S14 gene, we mutagenized a one-step CHO cell mutant and isolated second-step mutant clones resistant to 10-fold-higher concentrations of emetine. All of the highly resistant, two-step CHO cell mutants obtained displayed additional alterations in ribosomal protein S14. Hybridization complementation tests revealed that the two-step CHO cell emetine resistance mutants were members of the same complementation group defined by one-step CHO cell mutants, EmtB. Two-step mutants obtained from a Chinese hamster lung cell emetine-resistant clone belong to the EmtA complementation group. The two-step and EmtB mutants elaborated 40S ribosomal subunits, which dissociated to 32S and 40S core particles in buffers containing 0.5 M KCl at 4 degrees C. In contrast, 40S ribosomal subunits purified from all EmtA, one-step EmtB EmtC mutants, and wild-type CHO and lung cells were stable at this temperature in buffers containing substantially higher concentrations of salt. Thus, two-step emtB mutations affect the structure of S14 protein directly and the stability of the 40S ribosomal subunit indirectly.

scholarly journals The modifying enzyme Tsr3 establishes the hierarchy of Rio kinase activity in 40S ribosome assembly

2021 ◽  
Author(s):  
Haina Huang ◽  
Melissa Parker ◽  
Katrin Karbstein
Keyword(s):  
Quality Control ◽  
Binding Site ◽  
Ribosomal Rna ◽  
Ribosomal Proteins ◽  
Kinase Activity ◽  
Ribosomal Subunit ◽  
Ribosome Assembly ◽  
Small Ribosomal Subunit ◽  
Yeast Strains

AbstractRibosome assembly is an intricate process, which in eukaryotes is promoted by a large machinery comprised of over 200 assembly factors (AF) that enable the modification, folding, and processing of the ribosomal RNA (rRNA) and the binding of the 79 ribosomal proteins. While some early assembly steps occur via parallel pathways, the process overall is highly hierarchical, which allows for the integration of maturation steps with quality control processes that ensure only fully and correctly assembled subunits are released into the translating pool. How exactly this hierarchy is established, in particular given that there are many instances of RNA substrate “handover” from one highly related AF to another remains to be determined. Here we have investigated the role of Tsr3, which installs a universally conserved modification in the P-site of the small ribosomal subunit late in assembly. Our data demonstrate that Tsr3 separates the activities of the Rio kinases, Rio2 and Rio1, with whom it shares a binding site. By binding after Rio2 dissociation, Tsr3 prevents rebinding of Rio2, promoting forward assembly. After rRNA modification is complete, Tsr3 dissociates, thereby allowing for recruitment of Rio1. Inactive Tsr3 blocks Rio1, which can be rescued using mutants that bypass the requirement for Rio1 activity. Finally, yeast strains lacking Tsr3 randomize the binding of the two kinases, leading to the release of immature ribosomes into the translating pool. These data demonstrate a role for Tsr3 and its modification activity in establishing a hierarchy for the function of the Rio kinases.

scholarly journals A DEAD-box protein regulates ribosome assembly through control of ribosomal protein synthesis

2019 ◽  
Vol 47 (15) ◽  
pp. 8193-8206 ◽  
Author(s):  
Isabelle Iost ◽  
Chaitanya Jain
Keyword(s):  
Protein Synthesis ◽  
Ribosomal Proteins ◽  
Ribosomal Subunit ◽  
Large Family ◽  
Ribosome Assembly ◽  
Protein Abundance ◽  
Ribosomal Assembly ◽  
Dead Box ◽  
Ribosomal Protein Synthesis ◽  
Intrinsic Transcription Termination

Abstract DEAD-box proteins (DBPs) comprise a large family of proteins that most commonly have been identified as regulators of ribosome assembly. The Escherichia coli DBP, SrmB, represents a model bacterial DBP whose absence impairs formation of the large ribosomal subunit (LSU). To define the basis for SrmB function, suppressors of the ribosomal defect of ΔsrmB strains were isolated. The major class of suppressors was found to map to the 5′ untranslated region (UTR) of the rplM-rpsI operon, which encodes the ribosomal proteins (r-proteins) L13 and S9. An analysis of protein abundance indicated that both r-proteins are under-produced in the ΔsrmB strain, but are increased in these suppressors, implicating r-protein underproduction as the molecular basis for the observed ribosomal defects. Reduced r-protein synthesis was determined to be caused by intrinsic transcription termination within the rplM 5′ UTR that is abrogated by SrmB. These results reveal a specific mechanism for DBP regulation of ribosomal assembly, indirectly mediated through its effects on r-protein expression.

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