A Jun-binding protein related to a putative tumor suppressor.

Monteclaro, Felipe S.; Vogt, Peter K.

doi:10.1073/pnas.90.14.6726

Cited by 94 publications

(79 citation statements)

References 38 publications

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“…The findings that QSR1 homologues appear to be more highly expressed in undifferentiated mouse (6) and plant (8) cells are consistent with the fact that ribosomal genes are highly expressed in growing cells (29). In the cloning of jif-1, the chicken homologue of QSR1, it was found that Jif-1 interacts with c-Jun and that Jif-1 could disrupt Jun-Jun dimers (7). While it is conceivable that a cytoplasmic protein could translocate to the nucleus under some conditions and activate or repress transcription, it is also possible that the Jif-1/c-Jun interaction in vitro is a nonspecific interaction of the very basic Jif-1 with an acidic domain on c-Jun.…”

Section: Discussionmentioning

confidence: 55%

QSR1, an Essential Yeast Gene with a Genetic Relationship to a Subunit of the Mitochondrial Cytochromebc 1 Complex, Codes for a 60 S Ribosomal Subunit Protein

Dick¹,

Karamanou²,

Trumpower

1997

Journal of Biological Chemistry

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QSR1 (quinol-cytochrome c reductase subunit-requiring) is a highly conserved, essential gene in Saccharomyces cerevisiae that was identified through a synthetic lethal screen by its genetic relationship to QCR6, the gene for subunit 6 (Qcr6p) of the mitochondrial cytochrome bc 1 complex. The function of the QSR1-encoded protein (Qsr1p) and its relationship to the QCR6-encoded protein are unknown.When yeast cell lysates are fractionated by density gradient centrifugation, Qsr1p separates from organelles and sediments with a uniformly sized population of particles that are similar to eukaryotic ribosomes upon velocity gradient centrifugation. When 40 S and 60 S ribosomal subunits are separated on velocity gradients, Qsr1p is found exclusively with the 60 S subunits, where it is a stoichiometric component. Extracts prepared from qsr1-1 cells are defective in in vitro translation assays relative to the wild type.In yeast cell lysates in which QCR6 rescues an otherwise lethal qsr1-1 mutation, Qcr6p is found only in mitochondria, both in respiratory-competent cells and in rho 0 cells in which the bc 1 complex is no longer present. These results suggest that suppression of the qsr1-1 mutation by QCR6 occurs by a trans-relationship across the outer mitochondrial membrane.All cytochrome bc 1 complexes contain three redox proteins, cytochrome b, cytochrome c 1 , and an iron-sulfur protein, which are essential for the electron transfer and energy transduction functions of this enzyme in respiration and photosynthesis (1). The cytochrome bc 1 complexes of mitochondria also contain seven or eight additional subunits that lack prosthetic groups and that are not present in the bc 1 complexes of prokaryotes (2). The functions of these supernumerary subunits in the mitochondrial enzymes are largely unknown.QCR6 is the nuclear encoded gene for subunit 6 (Qcr6p) of the mitochondrial cytochrome bc 1 complex. Deletion of QCR6 does not impair growth of yeast on respiratory substrates at temperatures up to 35°C, indicating that the supernumerary subunit 6 is not essential for respiration, although the deletion does result in a temperature-sensitive petite phenotype at 37°C (3). To test whether the deletion of QCR6 might be covered by another, functionally redundant gene, we screened for mutants that require the nonessential subunit 6 and identified quinol-cytochrome c reductase subunit-requiring mutants in two complementation groups, which we named qsr1 and qsr2 (4). Surprisingly, the qsr mutants require QCR6 to grow on either fermentable or nonfermentable carbon sources. This suggests that subunit 6 of the cytochrome bc 1 complex has a role outside of respiration.QCR6 suppresses an otherwise lethal missense mutation in a qsr1-1 mutant. We cloned QSR1 by complementing the qsr1-1 mutant for growth in the absence of QCR6 and showed that QSR1 is an essential gene in yeast (4). The protein encoded by QSR1 is highly conserved and has been identified in at least 10 different eukaryotic organisms (4 -10). Comparisons of the amino acid sequen...

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Section: Discussionmentioning

confidence: 55%

QSR1, an Essential Yeast Gene with a Genetic Relationship to a Subunit of the Mitochondrial Cytochromebc 1 Complex, Codes for a 60 S Ribosomal Subunit Protein

Dick¹,

Karamanou²,

Trumpower

1997

Journal of Biological Chemistry

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“…Although a participation of the other two RPL10 proteins, B and C, in translation under UV-B light was not demonstrated here, it is still possible that these proteins may have a role under different UV-B light conditions or under a different developmental stage. Some evidence indicates that RPL10/QM act as coactivators/repressors of transcription in human, Entamoeba histolytica, and chicken (Monteclaro and Vogt, 1993;Stanbridge et al, 1994;Chávez-Ríos et al, 2003). QM protein has also been shown to interact with the proto-oncogene c-Yes, a Src family kinase, and it can thus participate in signal transduction pathways in different intracellular processes, including cell stability, division, proliferation, migration, and differentiation (Oh et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

“…For example, human L10 was first identified as QM, a putative suppressor of Wilms' tumor (Dowdy et al, 1991). QM is highly homologous to the Jun-binding protein (Jif-1), a putative tumor suppressor; it has been reported that Jif-1 forms a complex with c-Jun and represses its ability to transactivate gene expression via inhibition of binding of c-Jun to DNA (Monteclaro and Vogt, 1993). Most QM proteins are localized in the cytoplasm, and subcellular fractionation assays have shown that QM is peripherally localized to the endoplasmic reticulum (Nguyen et al, 1998).…”

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confidence: 99%

Plant L10 Ribosomal Proteins Have Different Roles during Development and Translation under Ultraviolet-B Stress

et al. 2010

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(J.B., A.L.B.) Ribosomal protein L10 (RPL10) proteins are ubiquitous in the plant kingdom. Arabidopsis (Arabidopsis thaliana) has three RPL10 genes encoding RPL10A to RPL10C proteins, while two genes are present in the maize (Zea mays) genome (rpl10-1 and rpl10-2). Maize and Arabidopsis RPL10s are tissue-specific and developmentally regulated, showing high levels of expression in tissues with active cell division. Coimmunoprecipitation experiments indicate that RPL10s in Arabidopsis associate with translation proteins, demonstrating that it is a component of the 80S ribosome. Previously, ultraviolet-B (UV-B) exposure was shown to increase the expression of a number of maize ribosomal protein genes, including rpl10. In this work, we demonstrate that maize rpl10 genes are induced by UV-B while Arabidopsis RPL10s are differentially regulated by this radiation: RPL10A is not UV-B regulated, RPL10B is down-regulated, while RPL10C is up-regulated by UV-B in all organs studied. Characterization of Arabidopsis T-DNA insertional mutants indicates that RPL10 genes are not functionally equivalent. rpl10A and rpl10B mutant plants show different phenotypes: knockout rpl10A mutants are lethal, rpl10A heterozygous plants are deficient in translation under UV-B conditions, and knockdown homozygous rpl10B mutants show abnormal growth. Based on the results described here, RPL10 genes are not redundant and participate in development and translation under UV-B stress.

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“…These observations show an inverse correlation between QM levels and the differentiation status and are consistent with some early in vitro data suggesting QM protein as a putative tumor suppressor gene. 8,25 Thus, downregulation of QM may be associated with the development of prostate cancer in humans and may be used as a marker for early stage of prostate cancer. In this study, the expression of QM protein in prostate tumor cells did not correlate with the extra-prostatic extension or high tumor volume, but correlated with the low-grade prostatic adenocarcinoma (Gleason grade 3), and with the low percentages of the prostatic gland involvement.…”

Section: Discussionmentioning

confidence: 99%

“…Both human QM and chicken homolog of QM/Jif-1 was reported to interact with the transcription factor c-Jun and thus inhibited cJun to activate genes containing AP-1 binding sites. 7,8 Although some investigators report that such interaction rarely occurs in vivo, 9 others further show that the interaction with c-Jun occurs via binding to the leucine zipper region of c-Jun, which is controlled by a protein kinase C phosphorylation event via zinc domain. 10 C-Jun and c-Fos are transcription factor subunits that bind as a homo or hetero-dimer complex to the AP-1 binding site in the promoter regions of many genes, especially those regulated by sex hormones.…”

Section: Introductionmentioning

confidence: 99%

Reduction of QM protein expression correlates with tumor grade in prostatic adenocarcinoma

Altınok

Powell

Che

et al. 2005

Prostate Cancer Prostatic Dis

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The QM protein is a transcription cofactor inhibiting the activity of AP-1 transcription factors and is also a ribosomal protein participating in protein synthesis. While protein synthesis is known to be increased in many cancers, inhibition of AP-1 activity presumably suppresses development and growth of sex-hormone-regulated tumor cells. The present study is the first report on immunohistochemical data of QM in human prostatic tissues. Paraffin sections of human prostate cancer samples were immunohistochemically stained for QM. The staining scores were analyzed with the clinicopathologic data of the patients. QM protein expression was found in all normal prostate glands adjacent to prostate cancer and in various intraepithelial neoplasia (PIN). In prostate cancer, the staining intensity and stained areas were decreased, compared to the normal glands and PIN lesions; in high-grade tumors only some patches of tumor cells showed positivity. Intense (3 þ ) staining was mostly observed in the Gleason grade three areas (48%) compared to grade 4 and 5 areas (22%), although both low and high-grade tumors showed similar percentages of weakly stained areas. Moreover, staining in prostatic adenocarcinoma was often topographically patchy and varied from negative or weak (1 þ ) to intense (3 þ ). There was an inverse correlation from normal to low-grade tumors and then to high-grade tumors. However, in high-grade tumors, the positive areas were mostly confined to peripheral aspects of tumors and were particularly strong in foci of perineural invasion. This preliminary study suggests that decreased QM expression may be associated with early development of prostate cancer, but later a high level of QM may facilitate progression of the tumors to a more aggressive phenotype.

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A Jun-binding protein related to a putative tumor suppressor.

Cited by 94 publications

References 38 publications

QSR1, an Essential Yeast Gene with a Genetic Relationship to a Subunit of the Mitochondrial Cytochromebc 1 Complex, Codes for a 60 S Ribosomal Subunit Protein

QSR1, an Essential Yeast Gene with a Genetic Relationship to a Subunit of the Mitochondrial Cytochromebc 1 Complex, Codes for a 60 S Ribosomal Subunit Protein

Plant L10 Ribosomal Proteins Have Different Roles during Development and Translation under Ultraviolet-B Stress

Reduction of QM protein expression correlates with tumor grade in prostatic adenocarcinoma

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