Chloroplast ribosomal protein L-18 in Chlamydomonas reinhardtii is processed during ribosome assembly

1988 ◽  
Vol 214 (3) ◽  
pp. 588-591 ◽  
Author(s):  
Xiang-Qin Liu ◽  
Nicholas W. Gillham ◽  
John E. Boynton
Keyword(s):  
Ribosomal Protein ◽  
Chlamydomonas Reinhardtii ◽  
Ribosome Assembly ◽  
Protein L

Processing of the precursor to a chloroplast ribosomal protein made in the cytosol occurs in two steps, one of which depends on a protein made in the chloroplast

1985 ◽  
Vol 5 (5) ◽  
pp. 1093-1099
Author(s):  
R J Schmidt ◽  
N W Gillham ◽  
J E Boynton
Keyword(s):  
Molecular Weight ◽  
Protein Synthesis ◽  
Ribosomal Protein ◽  
Apparent Molecular Weight ◽  
Protein L ◽  
Mature Form ◽  
Chloroplast Protein Synthesis ◽  
Made In

In pulse-chase experiments in which log-phase cells of Chlamydomonas reinhardtii were labeled in vivo for 5 min with H2(35)SO4, fluorographs of immunoprecipitates from whole cell extracts revealed that chloroplast ribosomal proteins L-2, L-6, L-21, and L-29, which are made in the cytosol and imported, appeared in their mature forms. However, in the case of chloroplast ribosomal protein L-18, which is also made in the cytoplasm and imported, a prominent precursor with an apparent molecular weight of 17,000 was found at the end of a 5-min pulse. This precursor was processed to its mature size (apparent molecular weight of 15,500) within the first 5 min of the subsequent chase. As determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the precursor to L-18 formed in vivo was 1.5 kilodaltons smaller than the primary product detected in translations of Chlamydomonas polyadenylated RNA in vitro. Upon a 10-min incubation with a postribosomal supernatant from Chlamydomonas, the 18,500-dalton precursor detected in vitro could be partially converted into a polypeptide that comigrated with the 17,000-dalton precursor detected in extracts of cells labeled in vivo. Under conditions in which the total amounts of chloroplast proteins had been reduced and cells were made to synthesize ribosomes rapidly, the apparent half-life of the 17,000-dalton precursor was extended over that seen in log-phase cells. When chloroplast protein synthesis was inhibited with lincomycin for 3 h before labeling under these conditions, the 17,000-dalton L-18 precursor but not the mature form was found, and the precursor was slowly degraded during a 60-min chase. When cells were placed in the dark for 3 h before labeling, processing of this precursor to the mature form appeared unaffected, but the chloroplast-synthesized ribosomal protein L-26 was detected, indicating that chloroplast protein synthesis was still occurring. We interpret these results to indicate that the maturation of protein L-18 in vivo involves at least two processing steps, one of which depends on a protein made on chloroplast ribosomes.

THE INFLUENCE OF AND PEPTIDES ON MITOCHONDRIES STAIN AND L7A RIBOSOMES PROTEIN EXPRESSION DURING HUMAN PINEAL GLAND AND THYMUS CELL SENESCENCE

2020 ◽  
pp. 741-747
Author(s):  
О. М. Ивко ◽  
А. О. Дробинцева ◽  
Д. О. Леонтьева ◽  
И. М. Кветной ◽  
В. О. Полякова ◽  
...  
Keyword(s):  
Pineal Gland ◽  
Ribosomal Protein ◽  
Laser Scanning ◽  
Specific Effect ◽  
Cell Senescence ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Protein L ◽  
Mitotracker Red

Методом конфокальной лазерной сканирующей микроскопии верифицированы новые молекулярные мишени действия геропротекторных пептидов AEDG (эпиталона) и KE (вилона). Показано, что при старении клеток эпифиза и тимуса in vitro окраска митохондрий MitoTracker Red снижается, а синтез рибосомального белка L 7 A компенсаторно возрастает. Пептид AEDG в 1,5 раза повышал площадь окрашивания митохондрий MitoTracker Red и на 22 % снижал экспрессию белка рибосом L 7 A в культурах клеток эпифиза человека при их репликативном старении. Пептид KE в 1,5 раза повышал площадь окрашивания митохондрий MitoTracker Red и на 15 % снижал экспрессию белка рибосом L 7 A в культурах клеток тимуса человека при их репликативном старении. Можно предположить, что пептиды AEDG и KE обладают тканеспецифическим свойством, нормализующим функции митохондрий и рибосом пинеалоцитов и тимоцитов. It was verified new molecular targets of geroprotective activity of AEDG (epitalon) and KE (vilon) peptides by the method of confocal laser scanning microscopy. It was shown that the MitoTracker Red mitochondries staining decreased and L 7 A ribosomal protein synthesis compensatory increased during pineal and thymic cell senescence in vitro . AEDG peptide increases in 1,5 times the square of MitoTracker Red mitochondries staining and decreases on 22% the expression of ribosomal protein L 7 A in cultures of human pineal gland cells during its senescence. KE peptide increases in 1,5 times the square of MitoTracker Red mitochondries staining and decreases on 15% the expression of ribosomal protein L 7 A in cultures of human thymic cells during its senescence. The square of MitoTracker Red mitochondries staining decreases and the expression of L 7 A ribosomal protein compensatory increases during pineal gland and thymic cells senescence. We can suppose that AEDG and KE peptides have a tissue-specific effect that normalizes the functions of mitochondria and ribosomes of pinealocytes and thymocytes.

scholarly journals Dedicated chaperones coordinate co-translational regulation of ribosomal protein production with ribosome assembly to preserve proteostasis

2021 ◽  
Author(s):  
Benjamin Pillet ◽  
Alfonso Méndez-Godoy ◽  
Guillaume Murat ◽  
Sébastien Favre ◽  
Michael Stumpe ◽  
...  
Keyword(s):  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Translational Regulation ◽  
De Novo ◽  
Spatial Separation ◽  
Ribosome Assembly ◽  
Mrna Levels ◽  
Ribosomal Assembly ◽  
Surplus Production ◽  
Regulatory Machinery

AbstractThe biogenesis of eukaryotic ribosomes involves the ordered assembly of around 80 ribosomal proteins. Supplying equimolar amounts of assembly-competent ribosomal proteins is complicated by their aggregation propensity and the spatial separation of their location of synthesis and pre-ribosome incorporation. Recent evidence has highlighted that dedicated chaperones protect individual, unassembled ribosomal proteins on their path to the pre-ribosomal assembly site. Here, we show that the co-translational recognition of Rpl3 and Rpl4 by their respective dedicated chaperone, Rrb1 or Acl4, prevents the degradation of the encoding RPL3 and RPL4 mRNAs in the yeast Saccharomyces cerevisiae. In both cases, negative regulation of mRNA levels occurs when the availability of the dedicated chaperone is limited and the nascent ribosomal protein is instead accessible to a regulatory machinery consisting of the nascent-polypeptide associated complex and the Caf130-associated Ccr4-Not complex. Notably, deregulated expression of Rpl3 and Rpl4 leads to their massive aggregation and a perturbation of overall proteostasis in cells lacking the E3 ubiquitin ligase Tom1. Taken together, we have uncovered an unprecedented regulatory mechanism that adjusts the de novo synthesis of Rpl3 and Rpl4 to their actual consumption during ribosome assembly and, thereby, protects cells from the potentially detrimental effects of their surplus production.

Developmental expression and 5S rRNA-binding activity of Xenopus laevis ribosomal protein L5

1989 ◽  
Vol 9 (12) ◽  
pp. 5281-5288
Author(s):  
W M Wormington
Keyword(s):  
Ribosomal Protein ◽  
Mammalian Cells ◽  
Ribosomal Proteins ◽  
5S Rrna ◽  
Yeast Cells ◽  
Developmental Expression ◽  
Rrna Synthesis ◽  
Ribosome Assembly ◽  
Subunit Assembly ◽  
Ribosomal Protein L5

Ribosomal protein L5 binds specifically to 5S rRNA to form a complex that is a precursor to 60S subunit assembly in vivo. Analyses in yeast cells, mammalian cells, and Xenopus embryos have shown that the accumulation of L5 is not coordinated with the expression of other ribosomal proteins. In this study, the primary structure and developmental expression of Xenopus ribosomal protein L5 were examined to determine the basis for its distinct regulation. These analyses showed that L5 expression could either coincide with 5S rRNA synthesis and ribosome assembly or be controlled independently of these events at different stages of Xenopus development. L5 synthesis during oogenesis was uncoupled from the accumulation of 5S rRNa but coincided with subunit assembly. In early embryos, the inefficient translation of L5 mRNA resulted in the accumulation of a stable L5-5S rRNA complex before ribosome assembly at later stages of development. Additional results demonstrated that L5 protein synthesized in vitro bound specifically to 5S rRNA.

scholarly journals Developmental expression and 5S rRNA-binding activity of Xenopus laevis ribosomal protein L5.

1989 ◽  
Vol 9 (12) ◽  
pp. 5281-5288 ◽  
Author(s):  
W M Wormington
Keyword(s):  
Ribosomal Protein ◽  
Mammalian Cells ◽  
Ribosomal Proteins ◽  
5S Rrna ◽  
Yeast Cells ◽  
Developmental Expression ◽  
Rrna Synthesis ◽  
Ribosome Assembly ◽  
Subunit Assembly ◽  
Ribosomal Protein L5

Ribosomal protein L5 binds specifically to 5S rRNA to form a complex that is a precursor to 60S subunit assembly in vivo. Analyses in yeast cells, mammalian cells, and Xenopus embryos have shown that the accumulation of L5 is not coordinated with the expression of other ribosomal proteins. In this study, the primary structure and developmental expression of Xenopus ribosomal protein L5 were examined to determine the basis for its distinct regulation. These analyses showed that L5 expression could either coincide with 5S rRNA synthesis and ribosome assembly or be controlled independently of these events at different stages of Xenopus development. L5 synthesis during oogenesis was uncoupled from the accumulation of 5S rRNa but coincided with subunit assembly. In early embryos, the inefficient translation of L5 mRNA resulted in the accumulation of a stable L5-5S rRNA complex before ribosome assembly at later stages of development. Additional results demonstrated that L5 protein synthesized in vitro bound specifically to 5S rRNA.

scholarly journals Role and dynamics of the ribosomal protein P0 and its related trans -acting factor Mrt4 during ribosome assembly in Saccharomyces cerevisiae

2009 ◽  
Vol 37 (22) ◽  
pp. 7519-7532 ◽  
Author(s):  
María Rodríguez-Mateos ◽  
Juan J. García-Gómez ◽  
Rosario Francisco-Velilla ◽  
Miguel Remacha ◽  
Jesús de la Cruz ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ribosomal Protein ◽  
Ribosome Assembly ◽  
Ribosomal Protein P0

scholarly journals Processing of the precursor to a chloroplast ribosomal protein made in the cytosol occurs in two steps, one of which depends on a protein made in the chloroplast.

1985 ◽  
Vol 5 (5) ◽  
pp. 1093-1099 ◽  
Author(s):  
R J Schmidt ◽  
N W Gillham ◽  
J E Boynton
Keyword(s):  
Molecular Weight ◽  
Protein Synthesis ◽  
Ribosomal Protein ◽  
Apparent Molecular Weight ◽  
Protein L ◽  
Mature Form ◽  
Chloroplast Protein Synthesis ◽  
Made In

In pulse-chase experiments in which log-phase cells of Chlamydomonas reinhardtii were labeled in vivo for 5 min with H2(35)SO4, fluorographs of immunoprecipitates from whole cell extracts revealed that chloroplast ribosomal proteins L-2, L-6, L-21, and L-29, which are made in the cytosol and imported, appeared in their mature forms. However, in the case of chloroplast ribosomal protein L-18, which is also made in the cytoplasm and imported, a prominent precursor with an apparent molecular weight of 17,000 was found at the end of a 5-min pulse. This precursor was processed to its mature size (apparent molecular weight of 15,500) within the first 5 min of the subsequent chase. As determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the precursor to L-18 formed in vivo was 1.5 kilodaltons smaller than the primary product detected in translations of Chlamydomonas polyadenylated RNA in vitro. Upon a 10-min incubation with a postribosomal supernatant from Chlamydomonas, the 18,500-dalton precursor detected in vitro could be partially converted into a polypeptide that comigrated with the 17,000-dalton precursor detected in extracts of cells labeled in vivo. Under conditions in which the total amounts of chloroplast proteins had been reduced and cells were made to synthesize ribosomes rapidly, the apparent half-life of the 17,000-dalton precursor was extended over that seen in log-phase cells. When chloroplast protein synthesis was inhibited with lincomycin for 3 h before labeling under these conditions, the 17,000-dalton L-18 precursor but not the mature form was found, and the precursor was slowly degraded during a 60-min chase. When cells were placed in the dark for 3 h before labeling, processing of this precursor to the mature form appeared unaffected, but the chloroplast-synthesized ribosomal protein L-26 was detected, indicating that chloroplast protein synthesis was still occurring. We interpret these results to indicate that the maturation of protein L-18 in vivo involves at least two processing steps, one of which depends on a protein made on chloroplast ribosomes.

scholarly journals Saccharomyces cerevisiae Ribosomal Protein L26 Is Not Essential for Ribosome Assembly and Function

2012 ◽  
Vol 32 (16) ◽  
pp. 3228-3241 ◽  
Author(s):  
R. Babiano ◽  
M. Gamalinda ◽  
J. L. Woolford ◽  
J. de la Cruz
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ribosomal Protein ◽  
Ribosome Assembly ◽  
And Function
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