Atg17/FIP200 localizes to perilysosomal Ref(2)P aggregates and promotes autophagy by activation of Atg1 in Drosophila. Nagy, P; Kárpáti, M; Varga, A; Pircs, K; Venkei, Z; Takáts, S; Varga, K; Erdi, B; Hegedűs, K; Juhász, G Autophagy
10
453-67
2014
Kivonat megmutatása
Phagophore-derived autophagosomes deliver cytoplasmic material to lysosomes for degradation and reuse. Autophagy mediated by the incompletely characterized actions of Atg proteins is involved in numerous physiological and pathological settings including stress resistance, immunity, aging, cancer, and neurodegenerative diseases. Here we characterized Atg17/FIP200, the Drosophila ortholog of mammalian RB1CC1/FIP200, a proposed functional equivalent of yeast Atg17. Atg17 disruption inhibits basal, starvation-induced and developmental autophagy, and interferes with the programmed elimination of larval salivary glands and midgut during metamorphosis. Upon starvation, Atg17-positive structures appear at aggregates of the selective cargo Ref(2)P/p62 near lysosomes. This location may be similar to the perivacuolar PAS (phagophore assembly site) described in yeast. Drosophila Atg17 is a member of the Atg1 kinase complex as in mammals, and we showed that it binds to the other subunits including Atg1, Atg13, and Atg101 (C12orf44 in humans, 9430023L20Rik in mice and RGD1359310 in rats). Atg17 is required for the kinase activity of endogenous Atg1 in vivo, as loss of Atg17 prevents the Atg1-dependent shift of endogenous Atg13 to hyperphosphorylated forms, and also blocks punctate Atg1 localization during starvation. Finally, we found that Atg1 overexpression induces autophagy and reduces cell size in Atg17-null mutant fat body cells, and that overexpression of Atg17 promotes endogenous Atg13 phosphorylation and enhances autophagy in an Atg1-dependent manner in the fat body. We propose a model according to which the relative activity of Atg1, estimated by the ratio of hyper- to hypophosphorylated Atg13, contributes to setting low (basal) vs. high (starvation-induced) autophagy levels in Drosophila. | | 24419107
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Assessment of cytochrome C oxidase dysfunction in the substantia nigra/ventral tegmental area in schizophrenia. Rice, MW; Smith, KL; Roberts, RC; Perez-Costas, E; Melendez-Ferro, M PloS one
9
e100054
2014
Kivonat megmutatása
Perturbations in metabolism are a well-documented but complex facet of schizophrenia pathology. Optimal cellular performance requires the proper functioning of the electron transport chain, which is constituted by four enzymes located within the inner membrane of mitochondria. These enzymes create a proton gradient that is used to power the enzyme ATP synthase, producing ATP, which is crucial for the maintenance of cellular functioning. Anomalies in a single enzyme of the electron transport chain are sufficient to cause disruption of cellular metabolism. The last of these complexes is the cytochrome c oxidase (COX) enzyme, which is composed of thirteen different subunits. COX is a major site for oxidative phosphorylation, and anomalies in this enzyme are one of the most frequent causes of mitochondrial pathology. The objective of the present report was to assess if metabolic anomalies linked to COX dysfunction may contribute to substantia nigra/ventral tegmental area (SN/VTA) pathology in schizophrenia. We tested COX activity in postmortem SN/VTA from schizophrenia and non-psychiatric controls. We also tested the protein expression of key subunits for the assembly and activity of the enzyme, and the effect of antipsychotic medication on subunit expression. COX activity was not significantly different between schizophrenia and non-psychiatric controls. However, we found significant decreases in the expression of subunits II and IV-I of COX in schizophrenia. Interestingly, these decreases were observed in samples containing the entire rostro-caudal extent of the SN/VTA, while no significant differences were observed for samples containing only mid-caudal regions of the SN/VTA. Finally, rats chronically treated with antipsychotic drugs did not show significant changes in COX subunit expression. These findings suggest that COX subunit expression may be compromised in specific sub-regions of the SN/VTA (i.e. rostral regions), which may lead to a faulty assembly of the enzyme and a greater vulnerability to metabolic insult. | | 24941246
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Cancer somatic mutations disrupt functions of the EphA3 receptor tyrosine kinase through multiple mechanisms. Lisabeth, EM; Fernandez, C; Pasquale, EB Biochemistry
51
1464-75
2011
Kivonat megmutatása
The Eph receptor tyrosine kinases make up an important family of signal transduction molecules that control many cellular processes, including cell adhesion and movement, cell shape, and cell growth. All of these are important aspects of cancer progression, but the relationship between Eph receptors and cancer is complex and not fully understood. Genetic screens of tumor specimens from cancer patients have revealed somatic mutations in many Eph receptors. The most highly mutated Eph receptor is EphA3, but its functional role in cancer is currently not well established. Here we show that many EphA3 mutations identified in lung, colorectal, and hepatocellular cancers, melanoma, and glioblastoma impair kinase activity or ephrin ligand binding and/or decrease the level of receptor cell surface localization. These results suggest that EphA3 has ephrin- and kinase-dependent tumor suppressing activities, which are disrupted by somatic cancer mutations. | | 22242939
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Gateway-compatible transposon vector to genetically modify human embryonic kidney and adipose-derived stromal cells. Spyros Petrakis,Tamas Raskó,Lajos Mátés,Zoltan Ivics,Zsuzsanna Izsvák,Kokkona Kouzi-Koliakou,George Koliakos Biotechnology journal
7
2011
Kivonat megmutatása
The Gateway technology cloning system and transposon technology represent state-of-the-art laboratory techniques. Combination of these molecular tools allows rapid cloning of target genes into expression vectors. Here, we describe a novel Gateway technology-compatible transposon plasmid that combines the advantages of Gateway recombination cloning with the Sleeping Beauty (SB) transposon-mediated transgene integrations. In our system the transposition is catalyzed by the novel hyperactive SB100x transposase, and provides highly efficient and precise transgene integrations into the host genome. A Gateway-compatible transposon plasmid was generated in which the potential target gene can be fused with a yellow fluorescent protein (YFP) tag at the N-terminal. The vector utilizes the CAGGS promoter to control fusion protein expression. The transposon expression vector encoding the YFP-interferon-? protein (IFNB1) fusion protein together with the hyperactive SB100x transposase was used to generate stable cell lines in human embryonic kidney (HEK293) and rat adipose-derived stromal cells (ASC). ASCs and HEK293 cells stably expressed and secreted the human IFNB1 for up to 4 weeks after transfection. The generated Gateway-compatible transposon plasmid can be utilized for numerous experimental approaches, such as gene therapy or high-throughput screening methods in primary cells, representing a valuable molecular tool for laboratory applications. | | 22323455
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Dopamine pathology in schizophrenia: analysis of total and phosphorylated tyrosine hydroxylase in the substantia nigra. Perez-Costas, E; Melendez-Ferro, M; Rice, MW; Conley, RR; Roberts, RC Frontiers in psychiatry
3
31
2011
Kivonat megmutatása
Despite the importance of dopamine neurotransmission in schizophrenia, very few studies have addressed anomalies in the mesencephalic dopaminergic neurons of the substantia nigra/ventral tegmental area (SN/VTA). Tyrosine hydroxylase (TH) is the rate-limiting enzyme for the production of dopamine, and a possible contributor to the anomalies in the dopaminergic neurotransmission observed in schizophrenia.In this study, we had three objectives: (1) Compare TH expression (mRNA and protein) in the SN/VTA of schizophrenia and control postmortem samples. (2) Assess the effect of antipsychotic medications on the expression of TH in the SN/VTA. (3) Examine possible regional differences in TH expression anomalies within the SN/VTA.To achieve these objectives three independent studies were conducted: (1) A pilot study to compare TH mRNA and TH protein levels in the SN/VTA of postmortem samples from schizophrenia and controls. (2) A chronic treatment study was performed in rodents to assess the effect of antipsychotic medications in TH protein levels in the SN/VTA. (3) A second postmortem study was performed to assess TH and phosphorylated TH protein levels in two types of samples: schizophrenia and control samples containing the entire rostro-caudal extent of the SN/VTA, and schizophrenia and control samples containing only mid-caudal regions of the SN/VTA.Our studies showed impairment in the dopaminergic system in schizophrenia that could be mainly (or exclusively) located in the rostral region of the SN/VTA. Our studies also showed that TH protein levels were significantly abnormal in schizophrenia, while mRNA expression levels were not affected, indicating that TH pathology in this region may occur posttranscriptionally. Lastly, our antipsychotic animal treatment study showed that TH protein levels were not significantly affected by antipsychotic treatment, indicating that these anomalies are an intrinsic pathology rather than a treatment effect. | | 22509170
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Inactivation of Chikungunya virus by 1,5 iodonapthyl azide. Sharma, A; Gupta, P; Maheshwari, RK Virology journal
9
301
2011
Kivonat megmutatása
Chikungunya virus (CHIKV) is an arthropod borne alphavirus of the family Togaviridae. CHIKV is a reemerging virus for which there is no safe prophylactic vaccine. A live attenuated strain of CHIKV, CHIK181/25, was previously demonstrated to be highly immunogenic in humans, however, it showed residual virulence causing transient arthralgia.In this study, we demonstrate the complete inactivation of CHIKV181/25 by 1,5 iodonapthyl azide (INA). No cytopathic effect and virus replication was observed in cells infected with the INA-inactivated CHIKV. However, a reduction in the INA-inactivated CHIK virus-antibody binding capacity was observed by western blot analysis.INA completely inactivated CHIKV and can further be explored for developing an inactivated-CHIKV vaccine. | | 23210745
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Neurochemical characterization of the tree shrew dorsal striatum. Rice, MW; Roberts, RC; Melendez-Ferro, M; Perez-Costas, E Frontiers in neuroanatomy
5
53
2010
Kivonat megmutatása
The striatum is a major component of the basal ganglia and is associated with motor and cognitive functions. Striatal pathologies have been linked to several disorders, including Huntington's, Tourette's syndrome, obsessive-compulsive disorders, and schizophrenia. For the study of these striatal pathologies different animal models have been used, including rodents and non-human primates. Rodents lack on morphological complexity (for example, the lack of well defined caudate and putamen nuclei), which makes it difficult to translate data to the human paradigm. Primates, and especially higher primates, are the closest model to humans, but there are ever-increasing restrictions to the use of these animals for research. In our search for a non-primate animal model with a striatum that anatomically (and perhaps functionally) can resemble that of humans, we turned our attention to the tree shrew. Evolutionary genetic studies have provided strong data supporting that the tree shrews (Scadentia) are one of the closest groups to primates, although their brain anatomy has only been studied in detail for specific brain areas. Morphologically, the tree shrew striatum resembles the primate striatum with the presence of an internal capsule separating the caudate and putamen, but little is known about its neurochemical composition. Here we analyzed the expression of calcium-binding proteins, the presence and distribution of the striosome and matrix compartments (by the use of calbindin, tyrosine hydroxylase, and acetylcholinesterase immunohistochemistry), and the GABAergic system by immunohistochemistry against glutamic acid decarboxylase and Golgi impregnation. In summary, our results show that when compared to primates, the tree shrew dorsal striatum presents striking similarities in the distribution of most of the markers studied, while presenting some marked divergences when compared to the rodent striatum. | Western Blotting | 21887131
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Cadmium accumulation and metallothionein overexpression in internal spermatic vein of patients with varicocele. Shaw-Yeu Jeng, Su-Mei Wu, Jane-Dar Lee Urology
73
1231-5
2009
Kivonat megmutatása
OBJECTIVES: To determine the possible molecular mechanism for the thickened wall in the internal spermatic vein (ISV) of patients with varicocele, we examined the cadmium (Cd) content and metallothionein (MT) expression in these diseased vessels. Previous studies have shown that Cd might play a role in the etiology of varicocele-associated infertility. MT, a metal-binding protein, protects against cell apoptosis during hypoxia. METHODS: The study group consisted of 20 patients with grade 3 left varicocele. The control group consisted of 15 volunteers with left-sided indirect inguinal hernia. Through a left inguinal incision, a 1-cm section of the ISV was resected from each patient to measure the Cd and MT levels. The results were analyzed using Student's t test. RESULTS: The Cd content in the ISV was 59.84 +/- 5.7 ng/g in the control group and 192.1 +/- 24.2 ng/g in the varicocele group. The relative intensity of the MT band was 40.52 +/- 3.74 in the control group and 78.26 +/- 5.61 in the varicocele group. MT expression was greater in the varicocele group than in the control group, and its deposition in the vascular endothelial layer was predominant using immunohistochemistry staining and confocal laser scanning. CONCLUSIONS: The results of the present study have demonstrated a greater accumulation of Cd in the ISV of the varicocele group than in the control group. The high Cd content and hypoxic conditions would induce overexpression of MT in the diseased vessels to protect the vascular cells from apoptosis. This might be a mechanism for the thickened wall of the ISV in patients with varicocele. | | 19362335
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