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YY Stroylova JM Chobert VI Muronetz H Jakubowski T Haertlé 《Archives of biochemistry and biophysics》2012,526(1):29-37
Modification of protein lysyl residues by homocysteine (Hcy)-thiolactone generates proteins with altered structures and functions. It has been supposed to be one of the factors inducing protein condensation pathologies. To test a hypothesis that N-homocysteinylation may induce structural changes and in particular amyloidogenic conversion, ovine prion protein (PrP) was modified with Hcy-thiolactone and its physico-chemical properties were studied. N-Hcy-PrP formed insoluble multimers. Mass spectrometry analyses showed that at least K197 and K207 residues of PrP were the sites of N-homocysteinylation. Dynamic light scattering measurements revealed large aggregated N-Hcy-PrP particles of 1μm diameter. They were resistant to proteinase K digestion, and enhanced thioflavin T (ThT)-binding fluorescence, what is characteristic of amyloid structures. Infrared spectroscopy measurements showed increased content of beta-sheet in N-Hcy-PrP compared to unmodified PrP. Epifluorescence microscopy in the presence of ThT revealed cluster-like aggregates of N-Hcy-PrP. The collected data indicate that the N-homocysteinylation causes amyloidogenic transformation of PrP in vitro. 相似文献
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Proliferating cell nuclear antigen (PCNA) as a proliferative marker during embryonic and adult zebrafish hematopoiesis 总被引:4,自引:1,他引:3
Leung AY Leung JC Chan LY Ma ES Kwan TT Lai KN Meng A Liang R 《Histochemistry and cell biology》2005,124(2):105-111
We investigated the expression of proliferative cell nuclear antigen (PCNA) in zebrafish to delineate the proliferative hematopoietic
component during adult and embryonic hematopoiesis. Immunostaining for PCNA and enhanced green fluorescence protein (eGFP)
was performed in wild-type and fli1-eGFP (endothelial marker) and gata1-eGFP (erythroid cell marker) transgenic fish. Expression
of PCNA mRNA was examined in wild-type and chordin morphant embryos. In adult zebrafish kidney, the renal tubules are surrounded
by endothelial cells and it is separated into hematopoietic and excretory compartments. PCNA was expressed in hematopoietic
progenitor cells but not in mature neutrophils, eosinophils or erythroid cells. Some PCNA+ cells are scattered in the hematopoietic
compartment of the kidney while others are closely associated with renal tubular cells. PCNA was also expressed in spermatogonial
stem cells and intestine crypts, consistent with its role in cell proliferation and DNA synthesis. In embryos, PCNA is expressed
in the brain, spinal cord and intermediate cell mass (ICM) at 24 h-post fertilization. In chordin morphants, PCNA is significantly
upregulated in the expanded ICM. Therefore, PCNA can be used to mark cell proliferation in zebrafish hematopoietic tissues
and to identify a population of progenitor cells whose significance would have to be further investigated. 相似文献
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Stroylova YY Zimny J Yousefi R Chobert JM Jakubowski H Muronetz VI Haertlé T 《Biochimica et biophysica acta》2011,1814(10):1234-1245
Elevated homocysteine levels are resulting in N-homocysteinylation of lysyl residues in proteins and they correlate with a number of human pathologies. However, the role of homocysteinylation of lysyl residues is still poorly known. In order to study the features of homocysteinylation of intrinsically unstructured proteins (IUP) bovine caseins were used as a model. α(S1)-, β- and κ-caseins, showing different aggregations and micelle formation, were modified with homocysteine-thiolactone and their physico-chemical properties were studied. Efficiency of homocysteine incorporation was estimated to be about 1.5, 2.1 and 1.3 homocysteyl residues per one β-, α(S1)-, and κ-casein molecule, respectively. Use of intrinsic and extrinsic fluorescent markers such as Trp, thioflavin T and ANS, reveal structural changes of casein structures after homocysteinylation reflected by an increase in beta-sheet content, which in some cases may be characteristic of amyloid-like transformations. CD spectra also show an increase in beta-sheet content of homocysteinylated caseins. Casein homocysteinylation leads in all cases to aggregation. The sizes of aggregates and aggregation rates were dependent on homocysteine thiolactone concentration and temperature. DLS and microscopic studies have revealed the formation of large aggregates of about 1-3μm. Homocysteinylation of α(S1)- and β-caseins results in formation of regular spheres. Homocysteinylated κ-casein forms thin unbranched fibrils about 400-800nm long. In case of κ-casein amyloidogenic effect of homocysteinylation was confirmed by Congo red spectra. Taken together, data indicate that N-homocysteinylation provokes significant changes in properties of native caseins. A comparison of amyloidogenic transformation of 3 different casein types, belonging to the IUP protein family, shows that the efficiency of amyloidogenic transformation upon homocysteinylation depends on micellization capacity, additional disulphide bonds and other structural features. 相似文献
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S. S. Kudryavtseva Y. Y. Stroylova I. A. Zanyatkin T. Haertle V. I. Muronetz 《Biochemistry. Biokhimii?a》2016,81(10):1213-1220
The possibility of inhibition of chaperonin functional activity by amyloid proteins was studied. It was found that the ovine prion protein PrP as well as its oligomeric and fibrillar forms are capable of binding with the chaperonin GroEL. Besides, GroEL was shown to promote amyloid aggregation of the monomeric and oligomeric PrP as well as PrP fibrils. The monomeric PrP was shown to inhibit the GroEL-assisted reactivation of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The oligomers of PrP decelerate the GroEL-assisted reactivation of GAPDH, and PrP fibrils did not affect this process. The chaperonin GroEL is capable of interacting with GAPDH and different PrP forms simultaneously. A possible role of the inhibition of chaperonins by amyloid proteins in the misfolding of the enzymes involved in cell metabolism and in progression of neurodegenerative diseases of amyloid nature is discussed. 相似文献
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采用80%丙酮提取物的水萃取部位,利用凝胶、MCI、反相碳18、及 Toyopearl Butyl-650C 柱色谱进行分离纯化得到7个黄酮和3个苯乙醇苷类化合物。根据化合物的波谱数据分析鉴定为槲皮素(1)、槲皮苷(2)、异懈皮苷(3)、芦丁(4)、异牡荆素(5)、牡荆素(6)、木犀草素-7-O-α-L-鼠李糖(1→6)-β-D-葡萄糖苷(7)、2-phenethylβ-D-glucoside(8)、icariside D1(9)、2-苯乙基-D-芸香甙(10)。其中化合物1-3、5-6、8-10为首次从本属植物中分离得到。 相似文献
7.
Lisa Yu Satbir Thakur Rebecca YY. Leong-Quong Keiko Suzuki Andy Pang Jeffrey D. Bjorge Karl Riabowol Donald J. Fujita 《PloS one》2013,8(4)
The INhibitor of Growth 1 (ING1) is stoichiometric member of histone deacetylase (HDAC) complexes and functions as an epigenetic regulator and a type II tumor suppressor. It impacts cell growth, aging, apoptosis, and DNA repair, by affecting chromatin conformation and gene expression. Down regulation and mislocalization of ING1 have been reported in diverse tumor types and Ser/Thr phosphorylation has been implicated in both of these processes. Here we demonstrate that both in vitro and in vivo, the tyrosine kinase Src is able to physically associate with, and phosphorylate ING1, which results in a nuclear to cytoplasmic relocalization of ING1 in cells and a decrease of ING1 stability. Functionally, Src antagonizes the ability of ING1 to induce apoptosis, most likely through relocalization of ING1 and down regulation of ING1 levels. These effects were due to both kinase-dependent and kinase-independent properties of Src, and were most apparent at elevated levels of Src expression. These findings suggest that Src may play a major role in regulating ING1 levels during tumorigenesis in those cancers in which high levels of Src expression or activity are present. These data represent the first report of tyrosine kinase-mediated regulation of ING1 levels and suggest that kinase activation can impact chromatin structure through the ING1 epigenetic regulator. 相似文献
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Y. Y. Stroylova G. G. Kiselev E. V. Schmalhausen V. I. Muronetz 《Biochemistry. Biokhimii?a》2014,79(8):761-775
This review highlights the modern perception of anomalous folding of the prion protein and the role of chaperones therein. Special attention is paid to prion proteins from mammalian species, which are prone to amyloid-like prion diseases due to a unique aggregation pathway. Despite being a significantly popular current subject of investigations, the etiology, structure, and function of both normal and anomalous prion proteins still hold many mysteries. The most interesting of those are connected to the interaction with chaperone system, which is responsible for stabilizing protein structure and disrupting aggregates. In the case of prion proteins the following question is of the most importance — can chaperones influence different stages of the formation of pathological aggregates (these vary from intermediate oligomers to mature amyloid-like fibrils) and the whole transition from native prion protein to its amyloid-like fibril-enriched form? The existing inconsistencies and ambiguities in the observations made so far can be attributed to the fact that most of the investigations did not take into account the type and functional state of the chaperones. This review discusses in detail our previous works that have demonstrated fundamental differences between eukaryotic and prokaryotic chaperones in the action exerted on the amyloid-like transformation of the prion protein along with the dependence of the observed effects on the functional state of the chaperone. 相似文献