Proteasome Inhibitors Restore to Normal the Decreased Levels of Protein Expression and Nucleolar Localization of Various Mutant Ribosomal S19 Proteins Identified in DBA Patients.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 185-185 ◽  
Author(s):  
Aurore Cretien ◽  
Alexis Proust ◽  
Hanna Gazda ◽  
Jorg Meerpohl ◽  
Charlotte Marie Niemeyer ◽  
...  
Keyword(s):  
Subcellular Localization ◽  
Protein Expression ◽  
Proteasome Inhibitors ◽  
Nucleolar Localization ◽  
Wild Type ◽  
Mutant Proteins ◽  
Expression Levels ◽  
Type Protein ◽  
Wild Type Protein ◽  
Proteosomal Degradation

Abstract Mutations in ribosomal protein S19 (RPS19) gene have been found in 25% of patients affected with Diamond-Blackfan anemia (DBA), a congenital erythroblastopenia. We have previously shown that several RPS19 mutant proteins (V15F, InsAG36, W33stop, Y48stop, R56stop, M75stop, R94stop, 274del31, InsG238, G127Q and L131P) exhibit decreased levels of protein expression and do not localize to the nucleolus like the wild type protein in transfected Cos-7 cells. In contrast, other mutants (W52C, T55M, R56Q, R62W, 24Del18, G120S) exhibit normal levels of protein expression and normal nucleolar localization. We hypothesized that decreased levels of expression of mutant proteins such as V15F, G127Q, and L131P may be due to proteosomal degradation. In order to validate our hypothesis, we analyzed the effects of two proteasome inhibitors (MG132 and lactacystin) on mutant RPS19 protein expression levels and their subcellular localization. Following treatment with proteosome inhibitors, the mutant proteins with missense mutations (V15F, G127Q and L131P) were expressed at levels similar to that of wild type protein and localized in the nucleolus. Similarly, proteasome inhibitors also restored the expression levels and normal subcellular localization to RPS19 with non-sense mutations (InsG238, R94stop, and 274del31) that resulted in the translation of RPS19 protein with at least 80 aminoacids. In marked contrast, proteosome inhibitors failed to restore the expression levels of RPS19 with the non-sense mutants that led to synthesis of shortened proteins (InsAG36, W33stop, Y48stop, R56stop, M75stop). Even in the presence of proteosome inhibitors we noted a dramatic decrease in the levels of expression of these mutant proteins and proteins expressed were localized in the cytoplasm. Our findings imply an important role for proteosomal degradation pathway in regulating the expression levels of RPS19. They further suggest that proteasome inhibitors could be considered as a potential treatment for some steroid resistant DBA affected individuals with specific RPS19 mutations.

scholarly journals S279 Point Mutations in Candida albicans Sterol 14-α Demethylase (CYP51) ReduceIn VitroInhibition by Fluconazole

2012 ◽  
Vol 56 (4) ◽  
pp. 2099-2107 ◽  
Author(s):  
Andrew G. S. Warrilow ◽  
Jonathan G. L. Mullins ◽  
Claire M. Hull ◽  
Josie E. Parker ◽  
David C. Lamb ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Point Mutations ◽  
Triazole Ring ◽  
Wild Type ◽  
Protein Activity ◽  
Content Type ◽  
Mutant Proteins ◽  
Type Protein ◽  
Wild Type Protein ◽  
Binding Spectra

ABSTRACTThe effects of S279F and S279Y point mutations inCandida albicansCYP51 (CaCYP51) on protein activity and on substrate (lanosterol) and azole antifungal binding were investigated. Both S279F and S279Y mutants bound lanosterol with 2-fold increased affinities (Ks, 7.1 and 8.0 μM, respectively) compared to the wild-type CaCYP51 protein (Ks, 13.5 μM). The S279F and S279Y mutants and the wild-type CaCYP51 protein bound fluconazole, voriconazole, and itraconazole tightly, producing typical type II binding spectra. However, the S279F and S279Y mutants had 4- to 5-fold lower affinities for fluconazole, 3.5-fold lower affinities for voriconazole, and 3.5- to 4-fold lower affinities for itraconazole than the wild-type CaCYP51 protein. The S279F and S279Y mutants gave 2.3- and 2.8-fold higher 50% inhibitory concentrations (IC50s) for fluconazole in a CYP51 reconstitution assay than the wild-type protein did. The increased fluconazole resistance conferred by the S279F and S279Y point mutations appeared to be mediated through a combination of a higher affinity for substrate and a lower affinity for fluconazole. In addition, lanosterol displaced fluconazole from the S279F and S279Y mutants but not from the wild-type protein. Molecular modeling of the wild-type protein indicated that the oxygen atom of S507 interacts with the second triazole ring of fluconazole, assisting in orientating fluconazole so that a more favorable binding conformation to heme is achieved. In contrast, in the two S279 mutant proteins, this S507-fluconazole interaction is absent, providing an explanation for the higherKdvalues observed.

scholarly journals Pathogenic FAM83G palmoplantar keratoderma mutations inhibit the PAWS1:CK1α association and attenuate Wnt signalling.

2020 ◽  
Vol 4 ◽  
pp. 133
Author(s):  
Kevin Z.L. Wu ◽  
Rebecca A. Jones ◽  
Theresa Tachie-Menson ◽  
Thomas J. Macartney ◽  
Nicola T. Wood ◽  
...  
Keyword(s):  
Gene Knockout ◽  
Wnt Signalling ◽  
Luciferase Reporter ◽  
Wild Type ◽  
Palmoplantar Keratoderma ◽  
Mutant Proteins ◽  
Recessive Mutations ◽  
Type Protein ◽  
Wild Type Protein ◽  
Equivalent Residue

Background: Two recessive mutations in the FAM83G gene, causing A34E and R52P amino acid substitutions in the DUF1669 domain of the PAWS1 protein, are associated with palmoplantar keratoderma (PPK) in humans and dogs respectively. We have previously reported that PAWS1 associates with the Ser/Thr protein kinase CK1α through the DUF1669 domain to mediate canonical Wnt signalling. Methods: Co-immunoprecipitation was used to investigate possible changes to PAWS1 interactors caused by the mutations. We also compared the stability of wild-type and mutant PAWS1 in cycloheximide-treated cells. Effects on Wnt signalling were determined using the TOPflash luciferase reporter assay in U2OS cells expressing PAWS1 mutant proteins. The ability of PAWS1 to induce axis duplication in Xenopus embryos was also tested. Finally, we knocked-in the A34E mutation at the native gene locus and measured Wnt-induced AXIN2 gene expression by RT-qPCR. Results: We show that these PAWS1A34E and PAWS1R52P mutants fail to interact with CK1α but, like the wild-type protein, do interact with CD2AP and SMAD1. Like cells carrying a PAWS1F296A mutation, which also abolishes CK1α binding, cells carrying the A34E and R52P mutants respond poorly to Wnt signalling to an extent resembling that observed in FAM83G gene knockout cells. Consistent with this observation, these mutants, in contrast to the wild-type protein, fail to induce axis duplication in Xenopus embryos. We also found that the A34E and R52P mutant proteins are less abundant than the native protein and appear to be less stable, both when overexpressed in FAM83G-knockout cells and when knocked-in at the native FAM83G locus. Ala34 of PAWS1 is conserved in all FAM83 proteins and mutating the equivalent residue in FAM83H (A31E) also abolishes interaction with CK1 isoforms. Conclusions: We propose that mutations in PAWS1 cause PPK pathogenesis through disruption of the CK1α interaction and attenuation of Wnt signalling.

scholarly journals Pathogenic FAM83G palmoplantar keratoderma mutations inhibit the PAWS1:CK1α association and attenuate Wnt signalling.

2019 ◽  
Vol 4 ◽  
pp. 133 ◽  
Author(s):  
Kevin Z.L. Wu ◽  
Rebecca A. Jones ◽  
Theresa Tachie-Menson ◽  
Thomas J. Macartney ◽  
Nicola T. Wood ◽  
...  
Keyword(s):  
Gene Knockout ◽  
Wnt Signalling ◽  
Luciferase Reporter ◽  
Wild Type ◽  
Palmoplantar Keratoderma ◽  
Mutant Proteins ◽  
Recessive Mutations ◽  
Type Protein ◽  
Wild Type Protein ◽  
Equivalent Residue

Background: Two recessive mutations in the FAM83G gene, causing A34E and R52P amino acid substitutions in the DUF1669 domain of the PAWS1 protein, are associated with palmoplantar keratoderma (PPK) in humans and dogs respectively. We have previously reported that PAWS1 associates with the Ser/Thr protein kinase CK1α through the DUF1669 domain to mediate canonical Wnt signalling. Methods: Co-immunoprecipitation was used to investigate possible changes to PAWS1 interactors caused by the mutations. We also compared the stability of wild-type and mutant PAWS1 in cycloheximide-treated cells. Effects on Wnt signalling were determined using the TOPflash luciferase reporter assay in U2OS cells expressing PAWS1 mutant proteins. The ability of PAWS1 to induce axis duplication in Xenopus embryos was also tested. Finally, we knocked-in the A34E mutation at the native gene locus and measured Wnt-induced AXIN2 gene expression by RT-qPCR. Results: We show that these PAWS1A34E and PAWS1R52P mutants fail to interact with CK1α but, like the wild-type protein, do interact with CD2AP and SMAD1. Like cells carrying a PAWS1F296A mutation, which also abolishes CK1α binding, cells carrying the A34E and R52P mutants respond poorly to Wnt signalling to an extent resembling that observed in FAM83G gene knockout cells. Consistent with this observation, these mutants, in contrast to the wild-type protein, fail to induce axis duplication in Xenopus embryos. We also found that the A34E and R52P mutant proteins are less abundant than the native protein and appear to be less stable, both when overexpressed in FAM83G-knockout cells and when knocked-in at the native FAM83G locus. Ala34 of PAWS1 is conserved in all FAM83 proteins and mutating the equivalent residue in FAM83H (A31E) also abolishes interaction with CK1 isoforms. Conclusions: We propose that mutations in PAWS1 cause PPK pathogenesis through disruption of the CK1α interaction and attenuation of Wnt signalling.

scholarly journals How to improve the modelling of proteins mutations? A preliminary assessment

2018 ◽  
Author(s):  
Carolina Napoli ◽  
Anna Marabotti
Keyword(s):  
Protein Structure ◽  
Single Point ◽  
Structural Features ◽  
Quality Parameters ◽  
Single Point Mutation ◽  
Wild Type ◽  
Mutant Proteins ◽  
Type Protein ◽  
Wild Type Protein ◽  
Modelling Strategies

Several programs have been developed that are able to replace a residue with another one in a protein structure, but usually they are not able to simulate the short- and long-range effects of a real single point mutation. We tested if the approach of re-modelling the entire protein structure of a mutant protein using the wild type structure as a template can correctly reproduce the structural features of mutant proteins. To do this, we selected a benchmark of 4 different families of proteins for which a large group of mutants are available in the PDB database and we used MODELLER by applying different modelling strategies. Our results showed that different starting templates of the same wild type protein can affect the structures of the mutants, and that often structural peculiarities attributed to the effect of the mutations are strictly related to low quality electron density or alterations in the quality parameters used to evaluate the proteins. In general, the standard modelling procedure allows creating mutants more similar to the wild type protein than to the mutant one, but we devised possible suggestions to improve the ability of this approach to predict the effects of mutations on protein structure.

scholarly journals How to improve the modelling of proteins mutations? A preliminary assessment

2018 ◽  
Author(s):  
Carolina Napoli ◽  
Anna Marabotti
Keyword(s):  
Protein Structure ◽  
Single Point ◽  
Structural Features ◽  
Quality Parameters ◽  
Single Point Mutation ◽  
Wild Type ◽  
Mutant Proteins ◽  
Type Protein ◽  
Wild Type Protein ◽  
Modelling Strategies

Several programs have been developed that are able to replace a residue with another one in a protein structure, but usually they are not able to simulate the short- and long-range effects of a real single point mutation. We tested if the approach of re-modelling the entire protein structure of a mutant protein using the wild type structure as a template can correctly reproduce the structural features of mutant proteins. To do this, we selected a benchmark of 4 different families of proteins for which a large group of mutants are available in the PDB database and we used MODELLER by applying different modelling strategies. Our results showed that different starting templates of the same wild type protein can affect the structures of the mutants, and that often structural peculiarities attributed to the effect of the mutations are strictly related to low quality electron density or alterations in the quality parameters used to evaluate the proteins. In general, the standard modelling procedure allows creating mutants more similar to the wild type protein than to the mutant one, but we devised possible suggestions to improve the ability of this approach to predict the effects of mutations on protein structure.

scholarly journals Dynamics of the Peripheral Membrane Protein P2 from Human Myelin Measured by Neutron Scattering—A Comparison between Wild-Type Protein and a Hinge Mutant

PLoS ONE ◽  
2015 ◽  
Vol 10 (6) ◽  
pp. e0128954 ◽  
Author(s):  
Saara Laulumaa ◽  
Tuomo Nieminen ◽  
Mari Lehtimäki ◽  
Shweta Aggarwal ◽  
Mikael Simons ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Neutron Scattering ◽  
Wild Type ◽  
Type Protein ◽  
Wild Type Protein ◽  
Peripheral Membrane Protein

Two novel mutations in Gli-similar 3 in patients with congenital hypothyroidism and thyroid dysgenesis

2021 ◽  
Author(s):  
Jie Lan ◽  
Chunhui Sun ◽  
Xinping Liang ◽  
Ruixin Ma ◽  
Yuhua Ji ◽  
...  
Keyword(s):  
Congenital Hypothyroidism ◽  
Transcriptional Activation ◽  
Luciferase Assay ◽  
Expression Vectors ◽  
Luciferase Reporter ◽  
Dominant Negative Effect ◽  
Wild Type ◽  
Thyroid Dysgenesis ◽  
Type Protein ◽  
Wild Type Protein

Abstract Background: Thyroid dysgenesis (TD) is the main cause of congenital hypothyroidism (CH). As variants of the transcription factor Gli-similar 3 (GLIS3) have been associated with CH and GLIS3 is one of candidate genes of TD, we screened and characterized GLIS3 mutations in Chinese patients with CH and TD.Methods: To detect mutations, we sequenced all GLIS3 exons in the peripheral blood genomic DNA isolated from 50 patients with TD and 100 healthy individuals. Wild-type and mutant expression vectors of Glis3 were constructed. Quantitative real-time PCR, western blotting, and double luciferase assay were performed to investigation the effect of the mutations on GLIS3 protein function and transcriptional activation.Results: Two novel heterozygous missense mutations, c.2710G>A (p.G904R) and c.2507C>A (p.P836Q), were detected in two unrelated patients. Functional studies revealed that p.G904R expression was 59.95% lower and p.P836Q was 31.23% lower than wild-type GLIS3 mRNA expression. The p.G904R mutation also resulted in lower GLIS3 protein expression compared with that encoded by wild-type GLIS3. Additionally, the luciferase reporter assay revealed that p.G904R mediated impaired transcriptional activation compared with the wild-type protein (p < 0.05) but did not have a dominant-negative effect on the wild-type protein.Conclusions: We for the first time screened and characterized the function of GLIS3 mutations in Chinese individuals with CH and TD. Our study not only broadens the GLIS3 mutation spectrum, but also provides further evidence that GLIS3 defects cause TD.

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