scholarly journals Chaperone-E3 Ligase Complex HSP70-CHIP Mediates Ubiquitination of Ribosomal Protein S3

2018 ◽  
Vol 19 (9) ◽  
pp. 2723 ◽  
Author(s):  
Inwoo Hwang ◽  
Sung-Woo Cho ◽  
Jee-Yin Ahn
Keyword(s):  
Ribosomal Protein ◽  
Ribosome Biogenesis ◽  
Ribosomal Subunit ◽  
E3 Ligase ◽  
Interacting Protein ◽  
Akt Activation ◽  
Protein Levels ◽  
40S Ribosomal Subunit ◽  
Subsequent Degradation ◽  
Ribosomal Protein S3

In addition to its role in ribosome biogenesis, ribosomal protein S3 (RPS3), a component of the 40S ribosomal subunit, has been suggested to possess several extraribosomal functions, including an apoptotic function. In this study, we demonstrated that in the mouse brain, the protein levels of RPS3 were altered by the degree of nutritional starvation and correlated with neuronal apoptosis. After endurable short-term starvation, the apoptotic function of RPS3 was suppressed by Akt activation and Akt-mediated T70 phosphorylation, whereas after prolonged starvation, the protein levels of RPS3 notably increased, and abundant neuronal death occurred. These events coincided with ubiquitination and subsequent degradation of RPS3, controlled by HSP70 and the cochaperone E3 ligase: carboxy terminus of heat shock protein 70-interacting protein (CHIP). Thus, our study points to an extraribosomal role of RPS3 in balancing neuronal survival or death depending on the degree of starvation through CHIP-mediated polyubiquitination and degradation.

PHOTACs Enable Optical Control of Protein Degradation

2019 ◽  
Author(s):  
Martin Reynders ◽  
Bryan Matsuura ◽  
Marleen Bérouti ◽  
Daniele Simoneschi ◽  
Antonio Marzio ◽  
...  
Keyword(s):  
Protein Degradation ◽  
E3 Ligase ◽  
Optical Control ◽  
Cellular Proteins ◽  
Bifunctional Molecules ◽  
Protein Levels ◽  
Lead Compounds ◽  
Subsequent Degradation ◽  
Temporal And Spatial ◽  
Precision Therapeutics

<p><i>PROTACs (proteolysis targeting chimeras) are bifunctional molecules that tag proteins for ubiquitylation by an E3 ligase complex and subsequent degradation by the proteasome. They have emerged as powerful tools to control the levels of specific cellular proteins and are on the verge of being clinically used. We now introduce photoswitchable PROTACs that can be activated with the temporal and spatial precision that light provides. These trifunctional molecules, which we named PHOTACs, consist of a ligand for an E3 ligase, a photoswitch, and a ligand for a protein of interest. We demonstrate this concept by using PHOTACs that target either BET family proteins (BRD2,3,4) or FKBP12. Our lead compounds display little or no activity in the dark but can be reversibly activated to varying degrees with different wavelengths of light. Our modular and generalizable approach provides a method for the optical control of protein levels with photopharmacology and could lead to new types of precision therapeutics that avoid undesired systemic toxicity.</i><b></b></p>

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 PHOTACs enable optical control of protein degradation

2020 ◽  
Vol 6 (8) ◽  
pp. eaay5064 ◽  
Author(s):  
Martin Reynders ◽  
Bryan S. Matsuura ◽  
Marleen Bérouti ◽  
Daniele Simoneschi ◽  
Antonio Marzio ◽  
...  
Keyword(s):  
Protein Degradation ◽  
E3 Ligase ◽  
Optical Control ◽  
Cellular Proteins ◽  
Modular Approach ◽  
Bifunctional Molecules ◽  
Protein Levels ◽  
Lead Compounds ◽  
Subsequent Degradation ◽  
Precision Therapeutics

PROTACs (PROteolysis TArgeting Chimeras) are bifunctional molecules that target proteins for ubiquitylation by an E3 ligase complex and subsequent degradation by the proteasome. They have emerged as powerful tools to control the levels of specific cellular proteins. We now introduce photoswitchable PROTACs that can be activated with the spatiotemporal precision that light provides. These trifunctional molecules, which we named PHOTACs (PHOtochemically TArgeting Chimeras), consist of a ligand for an E3 ligase, a photoswitch, and a ligand for a protein of interest. We demonstrate this concept by using PHOTACs that target either BET family proteins (BRD2,3,4) or FKBP12. Our lead compounds display little or no activity in the dark but can be reversibly activated with different wavelengths of light. Our modular approach provides a method for the optical control of protein levels with photopharmacology and could lead to new types of precision therapeutics that avoid undesired systemic toxicity.

Emetine resistance of Chinese hamster cells: structures of wild-type and mutant ribosomal protein S14 mRNAs

1985 ◽  
Vol 5 (7) ◽  
pp. 1655-1659
Author(s):  
D D Rhoads ◽  
D J Roufa
Keyword(s):  
Ribosomal Protein ◽  
Ribosomal Subunit ◽  
Chinese Hamster ◽  
Housekeeping Gene ◽  
Single Copy ◽  
Wild Type ◽  
Cho Cell ◽  
40S Ribosomal Subunit ◽  
And Function ◽  
Physical And Chemical

The Chinese hamster ovary (CHO) cell 40S ribosomal subunit protein S14 provides a unique opportunity to investigate an important mammalian housekeeping gene and its mRNA and protein products. The S14 gene appears to be single copy, and CHO cell S14 mutants have been isolated as emetine-resistant (emtB) clones in tissue culture. Thus, S14 is the only mammalian ribosomal protein whose gene structure and function are amenable to straightforward genetic and biochemical analysis. Recently, we isolated a wild-type Chinese hamster lung cell cDNA clone, pCS14-1, including an almost complete copy of the ribosomal protein S14 message (N. Nakamichi, D. D. Rhoads, and D. J. Roufa, J. Biol. Chem. 258: 13236-13242, 1983). Here we describe comparable cDNAs from wild-type and emtB CHO cells. We report both mRNA and polypeptide sequences of the wild-type and mutant ribosomal protein transcripts. As a consequence of the genetic methods used to obtain our emetine-resistant mutants, the emtB S14 cDNAs differ from wild-type cDNA by single-base changes. Physical and chemical features of polypeptides encoded by the cDNAs are consistent with well-characterized S14 protein polymorphisms. The three emtB mutations analyzed affect two adjacent arginine codons within the very basic S14 carboxyl region, indicating a significant role for this portion of the protein in the function and architecture of the mammalian 40S ribosomal subunit.

scholarly journals Emetine resistance of Chinese hamster cells: structures of wild-type and mutant ribosomal protein S14 mRNAs.

1985 ◽  
Vol 5 (7) ◽  
pp. 1655-1659 ◽  
Author(s):  
D D Rhoads ◽  
D J Roufa
Keyword(s):  
Ribosomal Protein ◽  
Ribosomal Subunit ◽  
Chinese Hamster ◽  
Housekeeping Gene ◽  
Single Copy ◽  
Wild Type ◽  
Cho Cell ◽  
40S Ribosomal Subunit ◽  
And Function ◽  
Physical And Chemical

The Chinese hamster ovary (CHO) cell 40S ribosomal subunit protein S14 provides a unique opportunity to investigate an important mammalian housekeeping gene and its mRNA and protein products. The S14 gene appears to be single copy, and CHO cell S14 mutants have been isolated as emetine-resistant (emtB) clones in tissue culture. Thus, S14 is the only mammalian ribosomal protein whose gene structure and function are amenable to straightforward genetic and biochemical analysis. Recently, we isolated a wild-type Chinese hamster lung cell cDNA clone, pCS14-1, including an almost complete copy of the ribosomal protein S14 message (N. Nakamichi, D. D. Rhoads, and D. J. Roufa, J. Biol. Chem. 258: 13236-13242, 1983). Here we describe comparable cDNAs from wild-type and emtB CHO cells. We report both mRNA and polypeptide sequences of the wild-type and mutant ribosomal protein transcripts. As a consequence of the genetic methods used to obtain our emetine-resistant mutants, the emtB S14 cDNAs differ from wild-type cDNA by single-base changes. Physical and chemical features of polypeptides encoded by the cDNAs are consistent with well-characterized S14 protein polymorphisms. The three emtB mutations analyzed affect two adjacent arginine codons within the very basic S14 carboxyl region, indicating a significant role for this portion of the protein in the function and architecture of the mammalian 40S ribosomal subunit.

scholarly journals Ubiquitylation by the Ltn1 E3 ligase protects 60S ribosomes from starvation-induced selective autophagy

2014 ◽  
Vol 204 (6) ◽  
pp. 909-917 ◽  
Author(s):  
Batool Ossareh-Nazari ◽  
Carlos A. Niño ◽  
Mario H. Bengtson ◽  
Joong-Won Lee ◽  
Claudio A.P. Joazeiro ◽  
...  
Keyword(s):  
Ribosomal Protein ◽  
Nitrogen Starvation ◽  
Ribosomal Subunit ◽  
E3 Ligase ◽  
Protein Translation ◽  
Nutrient Supply ◽  
Lysosomal Degradation ◽  
Ribosomal Subunits ◽  
E3 Ligases ◽  
Selective Autophagy

Autophagy, the process by which proteins or organelles are engulfed by autophagosomes and delivered for vacuolar/lysosomal degradation, is induced to ensure survival under starvation and other stresses. A selective autophagic pathway for 60S ribosomal subunits elicited by nitrogen starvation in yeast—ribophagy—was recently described and requires the Ubp3-Bre5 deubiquitylating enzyme. This discovery implied that an E3 ligases act upstream, whether inhibiting the process or providing an initial required signal. In this paper, we show that Ltn1/Rkr1, a 60S ribosome-associated E3 implicated in translational surveillance, acts as an inhibitor of 60S ribosomal subunit ribophagy and is antagonized by Ubp3. The ribosomal protein Rpl25 is a relevant target. Its ubiquitylation is Ltn1 dependent and Ubp3 reversed, and mutation of its ubiquitylation site rendered ribophagy less dependent on Ubp3. Consistently, the expression of Ltn1—but not Ubp3—rapidly decreased after starvation, presumably to allow ribophagy to proceed. Thus, Ltn1 and Ubp3-Bre5 likely contribute to adapt ribophagy activity to both nutrient supply and protein translation.

scholarly journals Recent Advances on the Structure and Function of RNA Acetyltransferase Kre33/NAT10

Cells ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 1035 ◽  
Author(s):  
Sophie Sleiman ◽  
Francois Dragon
Keyword(s):  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Ribosomal Subunit ◽  
40S Ribosomal Subunit ◽  
Functional Features ◽  
And Function ◽  
Progeria Syndrome ◽  
Hutchinson Gilford Progeria Syndrome ◽  
Nucleolar Rna

Ribosome biogenesis is one of the most energy demanding processes in the cell. In eukaryotes, the main steps of this process occur in the nucleolus and include pre-ribosomal RNA (pre-rRNA) processing, post-transcriptional modifications, and assembly of many non-ribosomal factors and ribosomal proteins in order to form mature and functional ribosomes. In yeast and humans, the nucleolar RNA acetyltransferase Kre33/NAT10 participates in different maturation events, such as acetylation and processing of 18S rRNA, and assembly of the 40S ribosomal subunit. Here, we review the structural and functional features of Kre33/NAT10 RNA acetyltransferase, and we underscore the importance of this enzyme in ribosome biogenesis, as well as in acetylation of non-ribosomal targets. We also report on the role of human NAT10 in Hutchinson–Gilford progeria syndrome.

scholarly journals Diamond Blackfan Anemia at the Crossroad between Ribosome Biogenesis and Heme Metabolism

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Deborah Chiabrando ◽  
Emanuela Tolosano
Keyword(s):  
Ribosomal Protein ◽  
Ribosome Biogenesis ◽  
Leukemia Virus ◽  
Ribosomal Subunit ◽  
Pure Red Cell Aplasia ◽  
Feline Leukemia Virus ◽  
Congenital Defects ◽  
Diamond Blackfan Anemia ◽  
Heme Metabolism ◽  
Gene Coding

Diamond-Blackfan anemia (DBA) is a rare, pure red-cell aplasia that presents during infancy. Approximately 40% of cases are associated with other congenital defects, particularly malformations of the upper limb or craniofacial region. Mutations in the gene coding for the ribosomal protein RPS19 have been identified in 25% of patients with DBA, with resulting impairment of 18S rRNA processing and 40S ribosomal subunit formation. Moreover, mutations in other ribosomal protein coding genes account for about 25% of other DBA cases. Recently, the analysis of mice from which the gene coding for the heme exporter Feline Leukemia Virus subgroup C Receptor (FLVCR1) is deleted suggested that this gene may be involved in the pathogenesis of DBA. FLVCR1-null mice show a phenotype resembling that of DBA patients, including erythroid failure and malformations. Interestingly, some DBA patients have disease linkage to chromosome 1q31, where FLVCR1 is mapped. Moreover, it has been reported that cells from DBA patients express alternatively spliced isoforms of FLVCR1 which encode non-functional proteins. Herein, we review the known roles of RPS19 and FLVCR1 in ribosome function and heme metabolism respectively, and discuss how the deficiency of a ribosomal protein or of a heme exporter may result in the same phenotype.

Changes in Ribosomal Protein S3 Immunoreactivity and its Protein Levels in the Gerbil Hippocampus Following Subacute and Chronic Restraint Stress

2012 ◽  
Vol 37 (7) ◽  
pp. 1428-1435 ◽  
Author(s):  
Joon Ha Park ◽  
Choong Hyun Lee ◽  
Bing Chun Yan ◽  
Ji Hyeon Ahn ◽  
Young Joo Lee ◽  
...  
Keyword(s):  
Ribosomal Protein ◽  
Restraint Stress ◽  
Chronic Restraint Stress ◽  
Protein Levels ◽  
Ribosomal Protein S3

scholarly journals Novel Stress-responsive Genes EMG1 and NOP14 Encode Conserved, Interacting Proteins Required for 40S Ribosome Biogenesis

2001 ◽  
Vol 12 (11) ◽  
pp. 3644-3657 ◽  
Author(s):  
Phillip C. C. Liu ◽  
Dennis J. Thiele
Keyword(s):  
Gene Expression ◽  
Ribosome Biogenesis ◽  
Expression Patterns ◽  
Ribosomal Subunit ◽  
Temperature Sensitive ◽  
Physical Interaction ◽  
Ribosomal Protein Genes ◽  
Yeast Saccharomyces Cerevisiae ◽  
40S Ribosomal Subunit ◽  
Responsive Gene

Under stressful conditions organisms adjust the synthesis, processing, and trafficking of molecules to allow survival from and recovery after stress. In baker's yeast Saccharomyces cerevisiae, the cellular production of ribosomes is tightly matched with environmental conditions and nutrient availability through coordinate transcriptional regulation of genes involved in ribosome biogenesis. On the basis of stress-responsive gene expression and functional studies, we have identified a novel, evolutionarily conserved gene, EMG1, that has similar stress-responsive gene expression patterns as ribosomal protein genes and is required for the biogenesis of the 40S ribosomal subunit. The Emg1 protein is distributed throughout the cell; however, its nuclear localization depends on physical interaction with a newly characterized nucleolar protein, Nop14. Yeast depleted of Nop14 or harboring a temperature-sensitive allele of emg1 have selectively reduced levels of the 20S pre-rRNA and mature18S rRNA and diminished cellular levels of the 40S ribosomal subunit. Neither Emg1 nor Nop14 contain any characterized functional motifs; however, isolation and functional analyses of mammalian orthologues of Emg1 and Nop14 suggest that these proteins are functionally conserved among eukaryotes. We conclude that Emg1 and Nop14 are novel proteins whose interaction is required for the maturation of the 18S rRNA and for 40S ribosome production.

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