Cytosol

Phát triển là quá trình kiểm soát sự biểu hiện gen, quá trình điều hòa phức tạp về cơ chế, cơ bản có 5 mức độ: 1- Sự xoắn của NST (Chromatin Packing) 2- Kiểm soát sự phiên mã (Transcriptional Control) 3- Điều hòa hậu phiên mã (Posttranscriptional) [Nhân tế bào (Nuclear levels)] 4- Kiểm soát sự giải mã (Translational Control) 5- Điều hòa hậu giải mã (Posttranslational Control) [Cytosol (Cytoplasmic levels)] Sự điều hòa phiên mã bởi những phân tử protein,yếu tố phiên mã (transcription factors -TF). Các phân tử protein này luôn hiện diện trong tế bào và bám...

62p bichtram1910 22-05-2012 250 38   Download

- Cytosol, môi trường lỏng bên trong tế bào bao gồm dịch tế bào và các bào quan hiện diện. - Chức năng chính của cytosol: môi trường hoạt động của tế bào, các phản ứng sinh học diễn ra trong cytosol cũng như hiện diện của hệ thống enzym nội bào. Nhân, (nucleus - trung tâm kiểm soát tế bào), bảo quản vật chất di truyền. Sự hiện diện của nhân con (nuleolus) bên trong nhân giúp sinh tổng hợp các hạt ribosome....

39p bichtram1910 22-05-2012 274 27   Download

An unconventional phospholipase D (PLD) activity was identified recently in Saccharomyces cerevisiae which is Ca2+-dependent, preferentially hydrolyses phosphatidylethanolamine (PtdEtn) and phosphatidylserine and does not catalyse a transphosphatidylation with primary short-chain alcohols. We have characterized the cytosolic and membrane-bound forms of the yeast PtdEtn-PLD and examined the regulation of its activity under certain growth, nutritional and stress conditions. Both forms of PtdEtn-PLD activity were similarly activated by Ca2+ ions in a biphasic manner.

10p system191 01-06-2013 36 4   Download

The goal of this study was to determine the effects of a putative specific cytosolic phospholipase A2 inhibitor, arachidonyl trifluoromethyl ketone (AACOCF3), on arachidonic acid (AA) release and lipid mediator biosynthesis by ionophore-stimulated human neutrophils. Initial studies indicated that AACOCF3 at concentrations 0–10 lM did not affect AA release from neutrophils. In contrast, AACOCF3 potently inhibited leukotriene B4 formation by ionophore-stimulated neutrophils (IC50  2.5 lM).

11p system191 01-06-2013 46 4   Download

The plastid transcription kinase (PTK), a component of the major RNA polymerase complex from mustard chloroplasts, has been implicated in redox-mediated regulation of plastid gene expression. A cloning strategy to define the PTK gene(s) resulted in the isolation of a full-length cDNA for a protein with overall high homology with the a subunit of cytosolic casein kinase (CK2) that contained an N-terminal extension for a putative plastid transit peptide.

9p system191 01-06-2013 46 4   Download

In a previous study, the S100A8/A9 protein, a Ca2+- and arachidonic acid-binding protein, abundant in neutrophil cytosol, was found to potentiate the activation of the redox component of the O2– generating oxidase in neutrophils, namely the membrane-bound flavocytochrome b, by the cytosolic phox proteins p67phox, p47phox and Rac ` (Doussiere J., Bouzidi F. and Vignais P.V. (2001) Biochem. Biophys. Res. Commun. 285, 1317–1320). This led us to check by immunoprecipitation and protein fractionation whether the cytosolic phox proteins could bind to S100A8/A9.

10p system191 01-06-2013 30 4   Download

To examine the role of the distal His42 residue in the catalytic mechanism of pea cytosolic ascorbate peroxidase, two site-directed variants were prepared in which His42 was replaced with alanine (H42A) or glutamic acid (H42E). Electronic spectra of the ferric derivatives of H42A and H42E (pH 7.0, l ¼ 0.10 M, 25.0 °C) revealed wavelength maxima [kmax (nm): 397, 509, % 540sh, 644 (H42A); 404, 516, % 538sh, 639 (H42E)] consistent with a predominantly fiveco-ordinate high-spin iron. The specific activity of H42E for oxidation of L-ascorbate (8.2 ± 0.

11p system191 01-06-2013 39 4   Download

To establish an infection, Yersinia pseudotuberculosis utilizes a plasmid-encoded type III secretion machine that permits the translocation of several anti-host factors into the cytosol of target eukaryotic cells. Secreted YopD is essential for this process. Pre-secretory stabilization of YopD is mediated by an interaction with its cognate chaperone, LcrH. YopD possesses LcrH binding domains located in the N-terminus and in a predicted amphipathic domain located near the C-terminus. This latter domain is also critical for Yersinia virulence. ...

10p research12 01-06-2013 49 3   Download

A cytosolic thyroid-hormone-binding protein (xCTBP), predominantly responsible for the major binding activity of T3 in the cytosol of Xenopus liver, has been shown to be identical to aldehyde dehydrogenase class 1 (ALDH1) [Yamauchi, K., Nakajima, J., Hayashi, H., Horiuchi, R. & Tata, J.R. (1999) J. Biol. Chem. 274, 8460–8469]. Within this paper we surveyed which signaling, and other, compounds affect the thyroid hormone binding activity and aldehyde dehydrogenase activity of recombinant Xenopus ALDH1 (xCTBP/xALDH1) while examining the relationship between these two activities....

8p research12 01-06-2013 38 4   Download

The eukaryotic glyoxylate cycle has been previously hypothesized to occur in the peroxisomal compartment, which in the yeast Saccharomyces cerevisiae additionally represents the sole site for fatty acid b-oxidation. The subcellular location of the key glyoxylate-cycle enzyme malate synthase 1 (Mls1p), an SKL-terminated protein, was examined in yeast cells grown on di€erent carbon sources.

8p research12 01-06-2013 42 4   Download

Fluorescence ratio imaging indicates that immobilized, aspirin-treated platelets, loaded with Fura-2, respond to inositol 1,4,5-trisphosphate- (InsP3)-generating agonists such as thrombin by high-frequency, irregular rises in cytosolic [Ca 2+ ] i with spikes that vary in peak level and peak-to-peak interval. This differs from the regular [Ca 2+ ] i oscillations observed inother, larger cells.

10p research12 29-04-2013 43 3   Download

Human tissues such as liver, small intestine, spleen and kidney contain a cytosolic b-glucosidase (CBG) that hydrolyses variousb-D-glycosides, but whose physiological function is not known. Here, we describe the ®rst hetero-logous expression of human CBG, a system that facili-tated a detailed assessment of the enzyme speci®city towards dietary glycosides.

10p research12 29-04-2013 48 3   Download

Mammalian adenylate cyclases are predicted to possess complex topologies, comprising two cassettes of six trans-membrane-spanningmotifs followedbyacytosolic, catalytic ATP-binding domain. Recent studies have begun to provide insights on the tertiary assembly of these proteins; crystal-lographic analysis has revealed that the two cytosolic domains dimerize to forma catalytic core, whilemore recent biochemical and cell biological analysis shows that the two transmembrane cassettes also associate to facilitate the functional assembly and trackingof the enzyme. ...

9p research12 23-04-2013 37 2   Download

Mammalian tubulins and actins attain their native con-formation following interactions with CCT (the cytosolic chaperonin containing t-complex polypeptide 1). To study the b-tubulin folding in lower eukaryotes, an isotype of b-tubulin (b-T1) from the Antarctic ciliate Euplotes focardii, was expressed in Escherichia coli. Folding analysis was performed by incubation of the 35 S-labeled, denatured b-T1 in the presence, or absence, of purified rabbit CCT and cofactor A, a polypeptide that stabilizes folded monomericb-tubulin. ...

7p tumor12 22-04-2013 51 3   Download

Protein histidine phosphorylation in eukaryotes has been sparsely studied compared to protein serine/threonine and tyrosine phosphorylation. In an attempt to rectify this by probing porcine liver cytosol with the phosphohistidine-containing peptide succinyl-Ala-His(P)-Pro-Phe-p-nitro-anilide (phosphopeptide I), we observed a phosphatase activity that was insensitive towards okadaic acid and EDTA.

8p tumor12 22-04-2013 37 2   Download

Previous results have shown that theoncoembryonicmarker a-fetoprotein (AFP) is able to induce apoptosis in tumor cells through activation of caspase 3, bypassing Fas-dependent and tumor necrosis factor receptor-dependent signaling. In this study we further investigate the molecular interactions involvedin the AFP-mediatedsignaling of apoptosis. We show that AFP treatment of tumor cells is accompaniedby cytosolic translocation of mitochondrial cytochromec.

12p tumor12 20-04-2013 45 2   Download

Monoclonal nonspecific suppressor factor (MNSF) is a cytokine with antigen nonspecific suppressive activity. MNSFb(a subunit of MNSF) is a 14.5kDa fusion protein consisting of a proteinwith 36%identitywith ubiquitin and ribosomal protein S30. The ubiquitin-like segment (Ubi-L) may be cleaved from MNSFbin the cytosol. Recently, we have observed that Ubi-L covalently binds to intracellular proteins in mitogen-activated murine T-helper type 2 clone, D.10 cells.

7p tumor12 20-04-2013 33 3   Download

The new antigen receptor (IgNAR) from sharks is a disul-phide bonded dimer of two protein chains,each containing one variable and five constant domains,and functions as an antibody. In order to assess the antigen-binding capabilities of isolated IgNAR variable domains (VNAR),we have con-structed anin vitro library incorporating synthetic CDR3 regions of 15–18 residues in length.

12p tumor12 20-04-2013 26 3   Download

In this article, we report the results of an analysis of the glycolytic enzyme enolase (2-phospho-D-glycerate hydro-lase) of Trypanosoma brucei. Enolase activity was detected in both bloodstream-form and procyclic insect-stage try-panosomes, although a 4.5-fold lower specific activity was found in the cultured procyclic homogenate. Subcellular localization analysis showed that the enzyme is only pre-sent in the cytosol.

9p tumor12 20-04-2013 29 3   Download

A Drosophila melanogaster cDNA clone (GH01916) encoding a putative 723-residue long (82 kDa) protein (CG 7415) and displaying 50% identity with mammalian cytosolic dipeptidyl aminopeptidase (DPP) III was func-tionally expressed in Schneider S2 cells. Immunocytochemi-cal studies using anti-(rat liver DPP III) Ig indicated the expression of this putative DPP III at the outer cell mem-brane and into the cytosol of transfected cells.

9p tumor12 20-04-2013 37 3   Download