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Masashi Tanaka

Publications and source records attributed to Masashi Tanaka.

At least 55 records · Page 3Linked to original sources
PubMed2004

Cardiomyocyte-specific Bcl-2 overexpression attenuates ischemia-reperfusion injury, immune response during acute rejection, and graft coronary artery disease.

After cardiac transplantation, graft damage occurs secondary to ischemia-reperfusion injury and acute rejection. This damage ultimately leads to the development of graft coronary artery disease (GCAD), which limits long-term graft survival. Apoptosis is directly involved in graft injury, contributing to the development of GCAD. To assess the role of the antiapoptotic factor Bcl-2 in the process of GCAD, we transplanted hearts from FVB transgenic mice overexpressing human Bcl-2 under the control of alpha-myosin heavy chain promoter into allogenic C57BL/6 mice. Bcl-2 overexpression led to reduced cytochrome c-mediated caspase-9-dependent cardiomyocyte apoptosis and local inflammation (neutrophil infiltration and proinflammatory cytokine production) in cardiac allografts during ischemia-reperfusion injury and also led to reduced immune responses (inflammatory cell infiltration, production of T(H)1 cytokines and chemokines, and expression of adhesion molecules) during acute and chronic rejection without affecting host CD4(+) and CD8(+) cell responses in the spleen. Thus, local Bcl-2 expression directly contributes to the modulation of local immune responses in allograft rejection, resulting in attenuated GCAD. In conclusion, our findings suggest that the modulation of Bcl-2 expression by pharmacologic up-regulation or gene transfer may be of clinical benefit in the short- and long-term function of cardiac allografts.

Animals↗
PubMed2004

Mitochondrial genome single nucleotide polymorphisms and their phenotypes in the Japanese.

Polymorphisms in the human mitochondrial genome have been used for the elucidation of phylogenetic relationships among various ethnic groups. Because analysis by mitochondrial genetics has detected pathogenic mutations causing mitochondrial encephalomyopathy or cardiomyopathy, most of the mitochondrial single nucleotide polymorphisms (mtSNPs) found in control subjects have been regarded as merely normal variants. However, we cannot exclude the possibility that the mitochondrial functional differences among individuals are ascribable at least in part to the mtSNPs of each individual. Human lifespan in ancient history was much shorter than that at the present time. Therefore, it is reasonable to speculate that certain mtSNPs that predispose one toward susceptibility to adult- or elderly-onset diseases, such as Parkinson's disease and Alzheimer's disease, have never been a target for natural selection in the past. Similarly, thrifty mtSNPs that had been advantageous for survival under severe famine or cold climate conditions might turn out to be related to satiation-related diseases, such as diabetes mellitus and obesity. To examine these hypotheses, we have constructed a mtSNP database by sequencing the entire mitochondrial genomes of 672 subjects: 96 in each of seven groups (i.e., centenarians, young obese or non-obese subjects, diabetic patients with or without major vascular involvement, patients with Parkinson's disease, and those with Alzheimer's disease).

Brain↗
PubMed2004

Lymphocyte changes in peripheral blood, spleen, and liver in DMBA-induced squamous cell carcinoma of mouse cheek skin.

The peripheral blood, spleen, and liver lymphocyte subsets of mice with experimental cheek skin carcinoma were determined. The carcinoma was induced by the topical application of 2% (w/v) 9,10-dimethyl-1,2-benzanthracene (DMBA) to cheek skin twice a week for 12 weeks, and it was examined macroscopically and histopathologically. The composition of lymphocyte subsets (T cells, B cells, CD4+ single-positive [SP] T cells, and CD8+SP T cells) in peripheral blood, spleen, and liver was determined by flow cytometry at 3-week intervals for up to 24 weeks. Spleens and livers were assessed by determining their content of natural killer (NK)T cells. The results showed histopathological progression of the skin lesions from papilloma to squamous cell carcinoma at week 12. Body weight was significantly reduced from weeks 15 to 24, and spleen weight was significantly increased at weeks 21 and 24, but liver weight was not significantly different from the control. The lymphocyte subset composition of peripheral blood showed significant elevation of T cells at weeks 6 and 9, followed by reduced levels at weeks 21 and 24, with significant reduction of B cells at weeks 6 and 9, followed by elevation at weeks 21 and 24. CD4+SP T-cell content was elevated at weeks 6, 9, and 12, and reduced at weeks 21 and 24. CD8+SP T-cell content was significantly reduced at weeks 6, 9, and 12, and elevated at weeks 21 and 24. The composition of the lymphocyte subsets in the spleen was similar to their composition in peripheral blood. The composition of both T and B cells in the liver was significantly different from that in the corresponding control group, but no significant differences were found in either CD4+SP or CD8+SP T cells. These findings revealed that the DMBA-induced cheek skin carcinoma in mice affected not only the lymphocyte subsets in peripheral blood, but the cells in the spleen and liver as well.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2004

Association of a 5178C-->A (Leu237Met) polymorphism in the mitochondrial DNA with a low prevalence of myocardial infarction in Japanese individuals.

Because mitochondria are the major sources of reactive oxygen species (ROS) in cells, certain alterations in mitochondrial functions can lead to metabolic perturbation in vascular endothelial cells and smooth muscle cells, resulting in vascular dysfunction. We previously demonstrated that a C --> A transversion in mitochondrial DNA (mtDNA) at nucleotide 5178 of the NADH dehydrogenase subunit 2 (ND2) gene, which results in a Lue --> Met substitution at amino acid 237, was found more frequently in Japanese centenarians than in controls. We also demonstrated that this Mt5178C --> A polymorphism has anti-atherosclerotic effects in diabetic subjects. We have now examined whether the Mt5178C --> A (Leu237Met) polymorphism in the mitochondrial ND2 gene is associated with a low prevalence of myocardial infarction (MI) in a case-control study. The genotype of ND2 gene was determined either with a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) or a colorimetry-based allele-specific DNA probe assay. Multivariate logistic regression analysis with adjustment for age, gender, body mass index, smoking status, hypertension, diabetes mellitus, hypercholesterolemia, and hyperuricemia revealed that the frequency of the Mt5178A genotype was significantly higher in controls than in subjects with MI. These results suggest that the 5178A genotype of mitochondrial ND2 gene polymorphism is protective against MI; and this effect would explain, at least in part, its contribution to longevity.

Aged↗
PubMed2004

Injectable bioartificial myocardial tissue for large-scale intramural cell transfer and functional recovery of injured heart muscle.

OBJECTIVES: Most tissue-engineering approaches to restore injured heart muscle result in distortion of left ventricular geometry. In the present study we suggest seeding embryonic stem cells in a liquid matrix for myocardial restoration. METHODS: Undifferentiated green fluorescent protein-labeled mouse embryonic stem cells (2 x 10 6 ) were seeded in Matrigel (B&D, Bedford, Mass). In a Lewis rat heterotopic heart transplant model an intramural left ventricular pouch was fashioned after ligation of the left anterior descending coronary artery. The liquid mixture (0.125 mL) was injected in the resulting infarcted area within the pouch and solidified within a few minutes after transplantation (37 degrees C). Five recipient groups were formed: transplanted healthy hearts (group I), infarcted control hearts (group II), matrix recipients alone (group III), the study group that received matrix plus cells (group IV), and a group that received embryonic stem cells alone (group V). After echocardiography 2 weeks later, the hearts were harvested and stained for green fluorescent protein and cardiac muscle markers (connexin 43 and alpha-sarcomeric actin). RESULTS: The graft formed a sustained structure within the injured area and prevented ventricular wall thinning. The inoculated cells remained viable and expressed connexin 43 and alpha-sarcomeric actin. Fractional shortening and regional contractility were better in animals that received bioartificial tissue grafts compared with control animals (infarcted, matrix only, and embryonic stem cells only: group I, 17.0% +/- 3.5%; group II, 6.6% +/- 2.1%; group III, 10.3% +/- 2.2%; group IV, 14.5% +/- 2.5%; and group V, 7.8% +/- 1.8%). CONCLUSIONS: Liquid bioartificial tissue containing embryonic stem cells constitutes a powerful new approach to restoring injured heart muscle without distorting its geometry and structure.

Animals↗
PubMed2004

Intermittent androgen suppression for locally advanced and metastatic prostate cancer: preliminary report of a prospective multicenter study.

OBJECTIVES: To clarify the effect of intermittent androgen suppression on the time to androgen-independent progression and changes in quality of life (QOL). METHODS: Patients with locally advanced or metastatic prostate cancer were treated with a combination of leuprolide acetate and flutamide for 36 weeks. When the serum prostate-specific antigen (PSA) levels at 24 and 32 weeks were less than 4.0 ng/mL, treatment was withheld until the PSA level reached 15 ng/mL or the pretreatment level. This cycle of on-treatment and off-treatment was repeated until PSA failure (three consecutive increases in PSA level greater than 4.0 ng/mL during the on-treatment period) or symptomatic progression was observed. Changes in QOL were assessed by a self-assessment questionnaire. RESULTS: Forty-nine patients (26 with T3N0M0, 8 with T2-T3N1M0, 2 with T4N0M0, and 13 with T2-T3N0M1) were enrolled. The mean follow-up period was 136.5 weeks. Thirty-one patients finished cycle 1, six finished cycle 2, and three finished cycle 3. The mean off-treatment duration in cycles 1, 2, and 3 was 46.1, 36.9, and 23.3 weeks, respectively. In the off-treatment period, statistically significant improvements in the QOL score were observed in the categories of potency (11.4 versus 2.4) and social/family well-being (20.3 versus 16.1) compared with those in the on-treatment period. PSA failure occurred in 6 patients (3 with T3N0M0 and 3 with T2-T3N1M0), and all patients were alive at last follow-up. CONCLUSIONS: Our interim analysis indicated that QOL is remarkably improved during the off-treatment period. Intermittent androgen suppression would be a viable option for treatment of advanced prostate cancer, although a randomized controlled study is required to determine whether intermittent androgen suppression prolongs the time to androgen-independent cancer. We will continue follow-up in this study to a minimum of 3 years.

Adenocarcinoma↗
PubMed2004

Mitochondrial DNA 3644T-->C mutation associated with bipolar disorder.

Mitochondrial dysfunction associated with mutant mitochondrial DNA (mtDNA) has been suggested in bipolar disorder, and comorbidity with neurodegenerative diseases was often noted. We examined the entire sequence of mtDNA in six subjects with bipolar disorder having comorbid somatic symptoms suggestive of mitochondrial disorders and found several uncharacterized homoplasmic nonsynonymous nucleotide substitutions of mtDNA. Of these, 3644C was found in 5 of 199 patients with bipolar disorder but in none of 258 controls (p = 0.015). The association was significant in the extended samples [bipolar disorder, 9/630 (1.43%); controls, 1/734 (0.14%); p = 0.007]. On the other hand, only 5 of 25 family members with this mutation developed bipolar disorder, of which 4 patients with 3644C had comorbid physical symptoms. The 3644T-->C mutation converts amino acid 113, valine, to alanine in the NADH-ubiquinone dehydrogenase subunit I, a subunit of complex I, and 113 valine is well conserved from Drosophila to 61 mammalian species. Using transmitochondrial cybrids, 3644T-->C was shown to decrease mitochondrial membrane potential and complex I activity compared with haplogroup-matched controls. According to human mitochondrial genome polymorphism databases, 3644C was not found in centenarians but was found in 3% of patients with Alzheimer disease and 2% with Parkinson disease. The result of modest functional impairment caused by 3644T-->C suggests that this mutation could increase the risk for bipolar disorder.

Adolescent↗
PubMed2004

Genetic risk for coronary artery disease in individuals with or without type 2 diabetes.

Given that a substantial proportion of individuals with coronary artery disease (CAD) also have type 2 diabetes, it is important to identify genes that confer susceptibility to CAD independently in subjects with type 2 diabetes and in those without this condition. A large-scale association study was performed to identify genes that confer susceptibility to CAD in either the absence or presence of type 2 diabetes. The study population comprised 5207 unrelated Japanese individuals, including 3085 subjects with CAD and 2122 controls. Among all subjects, 1704 individuals had type 2 diabetes and 3503 individuals did not have this condition. The genotypes for 33 polymorphisms of 27 candidate genes were determined with a fluorescence- or colorimetry-based allele-specific DNA primer-probe assay system. Multivariate logistic regression analysis with adjustment for age, body mass index, and the prevalence of smoking, hypertension, hypercholesterolemia, and hyperuricemia revealed that the following polymorphisms were significantly (P < 0.005) associated with CAD: the 1019C -->T of the connexin 37 gene for men with type 2 diabetes; the 2445G -->A in the fatty acid-binding protein 2 gene for women with this condition; the -863C-->A in the tumor necrosis factor-alpha gene, the -219G-->T in the apolipoprotein E gene, the 1019C-->T in the connexin 37 gene for men without type 2 diabetes; and the -482C-->T in the apolipoprotein C-III gene for women without this condition. Genotyping of these polymorphisms may prove informative for assessment of the genetic risk for CAD in the absence or presence of type 2 diabetes.

Aged↗
PubMed2004

Mitochondrial genome variation in eastern Asia and the peopling of Japan.

To construct an East Asia mitochondrial DNA (mtDNA) phylogeny, we sequenced the complete mitochondrial genomes of 672 Japanese individuals (http://www.giib.or.jp/mtsnp/index_e.html). This allowed us to perform a phylogenetic analysis with a pool of 942 Asiatic sequences. New clades and subclades emerged from the Japanese data. On the basis of this unequivocal phylogeny, we classified 4713 Asian partial mitochondrial sequences, with <10% ambiguity. Applying population and phylogeographic methods, we used these sequences to shed light on the controversial issue of the peopling of Japan. Population-based comparisons confirmed that present-day Japanese have their closest genetic affinity to northern Asian populations, especially to Koreans, which finding is congruent with the proposed Continental gene flow to Japan after the Yayoi period. This phylogeographic approach unraveled a high degree of differentiation in Paleolithic Japanese. Ancient southern and northern migrations were detected based on the existence of basic M and N lineages in Ryukyuans and Ainu. Direct connections with Tibet, parallel to those found for the Y-chromosome, were also apparent. Furthermore, the highest diversity found in Japan for some derived clades suggests that Japan could be included in an area of migratory expansion to Continental Asia. All the theories that have been proposed up to now to explain the peopling of Japan seem insufficient to accommodate fully this complex picture.

DNA, Mitochondrial↗
PubMed2004

Cysteinyl-tRNA(Cys) formation in Methanocaldococcus jannaschii: the mechanism is still unknown.

Most organisms form Cys-tRNA(Cys), an essential component for protein synthesis, through the action of cysteinyl-tRNA synthetase (CysRS). However, the genomes of Methanocaldococcus jannaschii, Methanothermobacter thermautotrophicus, and Methanopyrus kandleri do not contain a recognizable cysS gene encoding CysRS. It was reported that M. jannaschii prolyl-tRNA synthetase (C. Stathopoulos, T. Li, R. Longman, U. C. Vothknecht, H. D. Becker, M. Ibba, and D. Söll, Science 287:479-482, 2000; R. S. Lipman, K. R. Sowers, and Y. M. Hou, Biochemistry 39:7792-7798, 2000) or the M. jannaschii MJ1477 protein (C. Fabrega, M. A. Farrow, B. Mukhopadhyay, V. de Crécy-Lagard, A. R. Ortiz, and P. Schimmel, Nature 411:110-114, 2001) provides the "missing" CysRS activity for in vivo Cys-tRNA(Cys) formation. These conclusions were supported by complementation of temperature-sensitive Escherichia coli cysS(Ts) strain UQ818 with archaeal proS genes (encoding prolyl-tRNA synthetase) or with the Deinococcus radiodurans DR0705 gene, the ortholog of the MJ1477 gene. Here we show that E. coli UQ818 harbors a mutation (V27E) in CysRS; the largest differences compared to the wild-type enzyme are a fourfold increase in the K(m) for cysteine and a ninefold reduction in the k(cat) for ATP. While transformants of E. coli UQ818 with archaeal and bacterial cysS genes grew at a nonpermissive temperature, growth was also supported by elevated intracellular cysteine levels, e.g., by transformation with an E. coli cysE allele (encoding serine acetyltransferase) or by the addition of cysteine to the culture medium. An E. coli cysS deletion strain permitted a stringent complementation test; growth could be supported only by archaeal or bacterial cysS genes and not by archaeal proS genes or the D. radiodurans DR0705 gene. Construction of a D. radiodurans DR0705 deletion strain showed this gene to be dispensable. However, attempts to delete D. radiodurans cysS failed, suggesting that this is an essential Deinococcus gene. These results imply that it is not established that proS or MJ1477 gene products catalyze Cys-tRNA(Cys) synthesis in M. jannaschii. Thus, the mechanism of Cys-tRNA(Cys) formation in M. jannaschii still remains to be discovered.

Amino Acyl-tRNA Synthetases↗
PubMed2004

The combination of rat mast cell and rabbit aortic smooth muscle is the simple bioassay for the screening of anti-allergic ingredient from methanolic extract of Corydalis tuber.

We have assessed the release of histamine from mast cells by smooth muscle contraction. 0.3 microg/ml compound 48/80 showed no effect on concentration-response relationship of histamine in rabbit aorta. Compound 48/80 induced release of histamine from rat mast cells. When aorta was stimulated by compound 48/80 in the presence of mast cells, contraction was evoked in concentration-dependent manner. This mast cell-dependent contraction was completely blocked by H1 receptor antagonist, 1 microM diphenhydramine. When mast cells was treated with compound 48/80 inhibitor benzalkonium chloride, mast cell-dependent contraction was inhibited, although benzalkonium chloride itself showed no effect on concentration-response relationship of histamine in rabbit aorta. At high concentration of 10 microg/ml, benzalkonium chloride itself evoked histamine release from mast cells and indeed inhibitory effect of 10 microg/ml benzalkonium chloride on mast cell-dependent contraction was lower than that of 3 microg/ml. We have applied this bioassay to search anti-allergic ingredient from a total methanolic extract of Corydalis tuber (Corydalis turtschaninovii BESSER forma yanhusuo Y. H. CHOU et C. C. HSU). Successively, we have isolated five fractions. The fractions I-IV are identified to be corybulbine (1), tetrahydropalmatine (2), corydaline (3) and yuanhunine (4), respectively. Main component of fraction V is the mixture of 3 and canadine (5). Fractions II and V significantly inhibited mast cell-dependent contraction in rabbit aorta as well as inhibited histamine release from rat mast cells. Furthermore, fractions I, III and V inhibited histamine-induced contraction in rabbit aorta at non-competitive manner. From these results, combination of rat mast cells and rabbit aorta is good bioassay to search the anti-allergic ingredient, and we have obtained effective fractions from Corydalis tuber using this assay.

Animals↗
PubMed2004

Analysis of Deinococcus radiodurans's transcriptional response to ionizing radiation and desiccation reveals novel proteins that contribute to extreme radioresistance.

During the first hour after a sublethal dose of ionizing radiation, 72 genes were upregulated threefold or higher in D. radiodurans R1. Thirty-three of these loci were also among a set of 73 genes expressed in R1 cultures recovering from desiccation. The five transcripts most highly induced in response to each stress are the same and encode proteins of unknown function. The genes (ddrA, ddrB, ddrC, ddrD, and pprA) corresponding to these transcripts were deleted, both alone and in all possible two-way combinations. Characterization of the mutant strains defines three epistasis groups that reflect different cellular responses to ionizing radiation-induced damage. The ddrA and ddrB gene products have complementary activities and inactivating both loci generates a strain that is more sensitive to ionizing radiation than strains in which either single gene has been deleted. These proteins appear to mediate efficient RecA-independent processes connected to ionizing radiation resistance. The pprA gene product is not necessary for homologous recombination during natural transformation, but nevertheless may participate in a RecA-dependent process during recovery from radiation damage. These characterizations clearly demonstrate that novel mechanisms significantly contribute to the ionizing radiation resistance in D. radiodurans.

Deinococcus↗
PubMed2004

Insulin-like growth factor promotes engraftment, differentiation, and functional improvement after transfer of embryonic stem cells for myocardial restoration.

Insulin-like growth factor-1 (IGF-1) promotes myocyte proliferation and can reverse cardiac abnormalities when it is administered in the early fetal stage. Supplementation of a mouse embryonic stem cell (ESC) suspension with IGF-1 might enhance cellular engraftment and host organ-specific differentiation after injection in the area of acute myocardial injury. In the study reported here, we sought to enhance the restorative effect of ESCs in the injured heart by adding IGF-1 to the injected cell population. Green fluorescent protein (GFP)-labeled sv129 ESCs (2.5 x 10(5)) were injected into the ischemic area after left anterior descending (LAD) artery ligation in BalbC mice. Recombinant mouse IGF-1 (25 ng) was added to the cell suspension prior to the injection (n = 5). Echocardiography was performed before organ harvest 2 weeks later. The degree of restoration (ratio of GFP+ to infarct area), expression of cardiac markers by GFP+ cells, inflammatory response, and tumorigenicity were evaluated. Mice with LAD ligation only (n = 5) and ESC transfer without IGF-1 (n = 5) served as controls. ESCs formed viable grafts and improved cardiac function. Left ventricular wall thickness was higher in the IGF-1 group (p = .025). There was a trend toward higher fractional shortening in the IGF-treated group. Histological analysis demonstrated that IGF-1 promoted expression of alpha-sarcomeric actin (p = .015) and major histocompatibility complex class I (p = .01). IGF did not affect the cellular response to the donor cells or tumorigenicity. IGF-1 promotes expression of cardiomyocyte phenotype in ESCs in vivo. It should be considered as an adjuvant to cell transfer for myocardial restoration.

Actins↗
PubMed2004

[Prediction of genetic risk for hypertension].

BACKGROUND: Although genetic epidemiological studies have suggested that several genetic variants increase the risk for hypertension, the genes that underlie genetic susceptibility to this condition remain to be identified definitively. Large-scale association studies that examine many gene polymorphisms simultaneously are required to predict genetic risk for hypertension. METHODS AND RESULTS: The population of the present study comprised 1,940 unrelated Japanese individuals, including 1,067 subjects with hypertension (574 men, 493 women) and 873 controls (533 men, 340 women). The genotypes for 33 single nucleotide polymorphisms of 27 candidate genes were determined with a fluorescence- or colorimetry-based allele-specific DNA primer-probe assay system. Multivariate logistic regression analysis with adjustment for age, body mass index, and the prevalence of smoking, diabetes mellitus, hypercholesterolemia, and hyperuricemia revealed that two polymorphisms (825C -> T in the G protein beta3 subunit gene and 190G -> A in the CC chemokine receptor 2 gene) were significantly associated with hypertension in men and that one polymorphism (-238G -> A in the tumor necrosis factor- alpha gene) was significantly associated with hypertension in women. CONCLUSION: These results suggest that two and one genes may be susceptibility loci for hypertension in Japanese men and women, respectively, and that genotyping of these polymorphisms may prove informative for prediction of the genetic risk for hypertension.

Female↗
PubMed2004

[Haplotype analysis of single nucleotide polymorphisms of mitochondrial DNA].

Mitochondrial DNA (mtDNA) mutations observed in both non-coding control and coding regions are being used widely to characterize human evolution and for identification. Several methodological approaches have been available for detection of single nucleotide polymorphisms (SNPs). SNPs of the non-coding region were mainly analyzed by means of direct sequencing. Especially, sequence analysis of D-loop is often the final resort in forensic and ancient personal identification. However, sequencing is relatively expensive and time-consuming. Furthermore, because the mtDNA molecule is a single linked unit, the statistical significance in forensic cases requires mtDNA matching in comparison with large sequence data. In this study, we developed a procedure of technique simultaneous typing to 11 SNPs and 2 tandem repeat sites in the non-coding and coding region by use of allele-specific amplification. In an analysis to 631 unrelated Japanese individuals the 180 haplotypes were defined in this study, and the level of haplotypic diversity and random mach probability was similar to that obtained by sequencing of the human hypervariable region 1 in mtDNA. These results show the usefulness of mtDNA haplotype analysis by the presented method for personal identification.

Alleles↗
PubMed2003

Crystallization and X-ray analysis of the N-terminal core domain of a tumour-associated human DEAD-box RNA helicase, rck/p54.

The RCK gene was cloned on the basis of the t(11;14)(q23;q32) chromosome translocation observed in human B-cell lymphoma cell line RC-K8. This gene was found to be overexpressed in various kinds of tumours. The gene product, rck/p54, consisting of 472 amino-acid residues with molecular weight 53.2 kDa, belongs to the family of DEAD-box RNA helicases. Its ATP-dependent RNA-unwinding activity toward c-myc RNA molecules in vitro has recently been demonstrated. In the present study, limited proteolysis experiments of rck/p54 were used to truncate the N-terminal domain (residues 1-288; 31.8 kDa) of rck/p54, leading to successful crystallization of Nc-rck/p54, i.e. the N-terminal core domain (residues 70-288; 24.5 kDa) of rck/p54. Crystals of Nc-rck/p54 were grown to a size suitable for X-ray structure analysis using polyethylene glycol 3350 as the precipitant. The crystal belongs to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 65.5, b = 73.1, c = 84.8 A, and diffracts X-rays to beyond 2.0 A resolution.

Amino Acid Sequence↗
PubMed2003

An inhibitor of mitochondrial complex I, rotenone, inactivates proteasome by oxidative modification and induces aggregation of oxidized proteins in SH-SY5Y cells.

In Parkinson's disease, characteristic pathological features are the cell death of nigrostriatal dopamine neurons and the formation of Lewy bodies composed of oxidized proteins. Mitochondrial dysfunction and aggregation of abnormal proteins have been proposed to cause the pathological changes. However, the relation between these two factors remains to be clarified. In this study, the effects of mitochondrial dysfunction on the oxidative modification and accumulation of proteins were analyzed using an inhibitor of mitochondrial complex I, rotenone, and antibodies against acrolein- and dityrosine-modified proteins. Under conditions inducing mainly apoptosis in neuroblastoma SH-SY5Y cells, rotenone markedly increased oxidized proteins, especially those modified with acrolein, even though the increase in intracellular reactive oxygen and nitrogen species was only transient and was not so marked. In addition, the activity of the proteasome system degrading oxidized proteins was reduced profoundly after treatment with rotenone. The 20S beta subunit of proteasome was modified with acrolein, to which other acrolein-modified proteins were found to bind, as shown by coprecipitation with the antibody against 20S beta subunit. These results suggest that mitochondrial dysfunction, especially decreased activity of complex I, may reduce proteasome activity through oxidative modification of proteasome itself and aggregation with other oxidized proteins. This mechanism might account for the accumulation of modified protein and, at least partially, for cell death of the dopamine neurons in Parkinson's disease.

Acrolein↗