Search results for "BCE"

Flexible ferromagnetic filaments and the interface with biology

2009

Flexible ferromagnetic filaments are studied both theoretically and experimentally. Two main deformation modes of the filament at magnetic field inversion are theoretically described and observed experimentally by using DNA-linked chains of ferromagnetic particles. Anomalous orientation of ferromagnetic filaments perpendicular to AC field with a frequency which is high enough is predicted and confirmed experimentally. By experimental studies of magnetotactic bacteria it is demonstrated how these properties of ferromagnetic filaments may be used to measure the flexibility of the chain of magnetosomes.

The transmembrane Bax inhibitor motif (TMBIM) containing protein family: Tissue expression, intracellular localization and effects on the ER CA2+-fil…

2015

Abstract Bax inhibitor-1 (BI-1) is an evolutionarily conserved pH-dependent Ca2+ leak channel in the endoplasmic reticulum and the founding member of a family of six highly hydrophobic mammalian proteins named transmembrane BAX inhibitor motif containing (TMBIM) 1-6 with BI-1 being TMBIM6. Here we compared the structure, subcellular localization, tissue expression and the effect on the cellular Ca2+ homeostasis of all family members side by side. We found that all TMBIM proteins possess the di-aspartyl pH sensor responsible for pH sensing identified in TMBIM6 and its bacterial homologue BsYetJ. TMBIM1-3 and TMBIM4-6 represent two phylogenetically distinct groups that are localized in the Go…

Role of Human Sec63 in Modulating the Steady-State Levels of Multi-Spanning Membrane Proteins

2012

The Sec61 translocon of the endoplasmic reticulum (ER) membrane forms an aqueous pore, allowing polypeptides to be transferred across or integrated into membranes. Protein translocation into the ER can occur co- and posttranslationally. In yeast, posttranslational translocation involves the heptameric translocase complex including its Sec62p and Sec63p subunits. The mammalian ER membrane contains orthologs of yeast Sec62p and Sec63p, but their function is poorly understood. Here, we analyzed the effects of excess and deficit Sec63 on various ER cargoes using human cell culture systems. The overexpression of Sec63 reduces the steady-state levels of viral and cellular multi-spanning membrane …

Localization of the two constitutively expressed nitric oxide synthase isoforms (nNOS and eNOS) in the same cell types in the saccule maculae of the …

2003

There is growing evidence for a nitric oxide/cyclic GMP pathway of signal transduction in the vestibular system. Recently, two isoforms of nitric oxide (NO) synthase (nNOS and eNOS) and NO itself have been identified at the light microscopic level in the vestibulocochlear system of mice using specific antibodies and a new fluorescence indicator. In order to acquire more information about signal transduction and tissue modulation in this neuroepithelium at the cellular and subcellular levels, ultrathin sections of London Resin White-embedded saccule maculae of the frog Rana pipiens were incubated with various concentrations of commercially available antibodies to nNOS and eNOS. The immunorea…

2013

Clusterin, also known as apolipoprotein J, is expressed from a variety of tissues and implicated in pathological disorders such as neurodegenerative diseases, ischemia and cancer. In contrast to secretory clusterin (sCLU), which acts as an extracellular chaperone, the synthesis, subcellular localization and function(s) of intracellular CLU isoforms is currently a matter of intense discussion. By investigating human CLU mRNAs we here unravel mechanisms leading to the synthesis of distinct CLU protein isoforms and analyze their subcellular localization and their impact on apoptosis and on NF-κB-activity. Quantitative PCR-analyses revealed the expression of four different stress-inducible CLU …

Differential Distribution of Harmonin Isoforms and Their Possible Role in Usher-1 Protein Complexes in Mammalian Photoreceptor Cells

2003

PURPOSE. Human Usher syndrome is the most common form of combined deafness and blindness. Usher type I (USH1), the most severe form, is characterized by profound congenital deafness, constant vestibular dysfunction, and prepubertal onset retinitis pigmentosa. Previous studies have shown that the USH1-proteins myosin VIIa, harmonin, and cadherin 23 interact and form a functional network during hair cell differentiation in the inner ear. The purpose of the present study was to analyze the molecular and cellular functions of these USH1 proteins in the mammalian retina. METHODS. Antibodies to USH1 proteins were generated and used in Western blot analysis of subcellular photoreceptor fractions a…

Donnan phenomena in membranes with charge due to ion adsorption. Effects of the interaction between adsorbed charged groups

1993

A physical model for the modified Donnan phenomenon associated with ion adsorption on localized membrane sites is presented. This model accounts for the dependence of the concentration of adsorbed ions on electrolyte concentration and pH as it is influenced by the electrostatic interaction between adsorbed ions. The equilibrium thermodynamic concepts employed are based on the Donnan formalism for the ion equilibria between membrane and solution, and the Bragg–Williams approximation for an adsorption isotherm that incorported interaction between adsorbed ions. Our results include the concentration of charged groups in the membrane, the pH of the membrane phase solution, and the Donnan potent…

Vergleich der subcellulären Verteilung von 3H-Strophanthin und 3H-Digi-toxin im Meerschweinchenherzen / Comparison of the Subcellular Distribution of…

1969

Um Aufschlus uber den Wirkort von Herzglykosiden in der Herzmuskelzelle zu erhalten, wurde die subcellulare Verteilung von 3H-Digitoxin und 3H-Strophanthin untersucht und mit dem positiv inotropen Effekt verglichen. Meerschweinchenherzen wurden nach der Langendorff-Methode mit glykosidhaltiger Tyrodelosung (3 · 10−7 bzw. 2,8 · 10−7 g/ml; 37°C) perfundiert; die Kontraktionskraft wurde fortlaufend isotonisch registriert. Die Glykosidkonzentration in den einzelnen Fraktionen wurde nach Homogenisation, Differentialzentrifugation und Extraktion der Glykoside mit Toluol bzw. Dioxan mit einem Flussigkeitsszintillations-zahlgerat bestimmt. Die Ruckverteilung wahrend der Aufarbeitung wurde in Kontro…

Topics on n-ary algebras

2011

We describe the basic properties of two n-ary algebras, the Generalized Lie Algebras (GLAs) and, particularly, the Filippov (or n-Lie) algebras (FAs), and comment on their n-ary Poisson counterparts, the Generalized Poisson (GP) and Nambu-Poisson (N-P) structures. We describe the Filippov algebra cohomology relevant for the central extensions and infinitesimal deformations of FAs. It is seen that semisimple FAs do not admit central extensions and, moreover, that they are rigid. This extends the familiar Whitehead's lemma to all $n\geq 2$ FAs, n=2 being the standard Lie algebra case. When the n-bracket of the FAs is no longer required to be fully skewsymmetric one is led to the n-Leibniz (or…

Rapid inactivation and proteasome-mediated degradation of OGG1 contribute to the synergistic effect of hyperthermia on genotoxic treatments

2013

Inhibition of DNA repair has been proposed as a mechanism underlying heat-induced sensitization of tumour cells to some anticancer treatments. Base excision repair (BER) constitutes the main pathway for the repair of DNA lesions induced by oxidizing or alkylating agents. Here, we report that mild hyperthermia, without toxic consequences per se, affects cellular DNA glycosylase activities, thus impairing BER. Exposure of cells to mild hyperthermia leads to a rapid and selective inactivation of OGG1 (8-oxoguanine DNA glycosylase) associated with the relocalisation of the protein into a detergent-resistant cellular fraction. Following its inactivation, OGG1 is ubiquitinated and directed to pro…