Mitochondrial disulfide relay and its substrates: mechanisms in health and disease

Abstract

Eukaryotic cells harbor membrane-enclosed compartments to spatially separate different biochemical processes. As a result, proteins that become synthesized in the cytosol but fulfill their function in another compartment require translocation machineries. In the intermembrane space (IMS) of mitochondria, the mitochondrial disulfide relay is responsible for the import of many soluble proteins in an oxidation-dependent manner. These IMS proteins carry out important tasks and therefore their import, folding and maintenance are crucial for the remainder of the cell. In this review, we first describe the machinery for oxidative protein folding in the IMS and then focus on recent developments, which especially concern the mammalian machinery, its substrates and its physiological role.

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Characterisation and vascular expression of nitric oxide synthase 3 in amphibians

Abstract

In mammals, nitric oxide (NO) produced by nitric oxide synthase 3 (NOS3) localised in vascular endothelial cells is an important vasodilator but the presence of NOS3 in the endothelium of amphibians has been concluded to be absent, based on physiological studies. In this study, a nos3 cDNA was sequenced from the toad, Rhinella marina. The open reading frame of R. marina nos3 encoded an 1170 amino acid protein that showed 81 % sequence identity to the recently cloned Xenopus tropicalis nos3. Rhinella marina nos3 mRNA was expressed in a range of tissues and in the dorsal aorta and pulmonary, mesenteric, iliac and gastrocnemius arteries. Furthermore, nos3 mRNA was expressed in the aorta of Xenopus laevis and X. tropicalis. Quantitative real-time PCR showed that removal of the endothelium of the lateral aorta of R. marina significantly reduced the expression of nos3 mRNA compared to control aorta with the endothelium intact. However, in situ hybridisation was not able to detect any nos3 mRNA in the dorsal aorta of R. marina. Immunohistochemistry using a homologous R. marina NOS3 antibody showed immunoreactivity (IR) within the basal region of many endothelial cells of the dorsal aorta and iliac artery. NOS3-IR was also observed in the proximal tubules and collecting ducts of the kidney but not within the capillaries of the glomeruli. This is the first study to demonstrate that vascular endothelial cells of an amphibian express NOS3.

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Aberrant expression of the tight junction molecules claudin-1 and zonula occludens-1 mediates cell growth and invasion in oral squamous cell carcinoma

Publication date: November 2016
Source:Human Pathology, Volume 57
Author(s): Hamzah Babkair, Manabu Yamazaki, Md. Shihab Uddin, Satoshi Maruyama, Tatsuya Abé, Ahmed Essa, Yoshimasa Sumita, Md. Shahidul Ahsan, Wael Swelam, Jun Cheng, Takashi Saku
We reported that altered cell contact mediated by E-cadherin is an initial event in the pathogenesis of oral epithelial malignancies. To assess other effects of cell adhesion, we examined the expression levels of tight junction (TJ) molecules in oral carcinoma in situ (CIS) and squamous cell carcinoma (SCC). To identify changes in the expression of TJ molecules, we conducted an analysis of the immunohistochemical profiles of claudin-1 (CLDN-1) and zonula occludens-1 (ZO-1) in surgical specimens acquired from patients with oral SCC containing foci of epithelial dysplasia or from patients with CIS. We used immunofluorescence, Western blotting, reverse-transcription polymerase chain reaction, and RNA interference to evaluate the functions of CLDN-1 and ZO-1 in cultured oral SCC cells. TJ molecules were not detected in normal oral epithelial tissues but were expressed in SCC/CIS cells. ZO-1 was localized within the nucleus of proliferating cells. When CLDN-1 expression was inhibited by transfecting cells with specific small interference RNAs, SCC cells dissociated, and their ability to proliferate and invade Matrigel was inhibited. In contrast, although RNA interference–mediated inhibition of ZO-1 expression did not affect cell morphology, it inhibited cell proliferation and invasiveness. Our findings indicated that the detection of TJ molecules in the oral epithelia may serve as a marker for the malignant phenotype of cells in which CLDN-1 regulates proliferation and invasion.



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Olfactory Behaviors Assayed by Computer Tracking Of Drosophila in a Four-quadrant Olfactometer

We describe here a behavioral setup and data analysis method for assaying olfactory responses of up to 100 vinegar flies (Drosophila melanogaster). This system may be used with single or multiple olfactory stimuli, and adaptable for optogenetic activation or silencing of neuronal subsets.

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Triple-Quadrupole Inductively Coupled Plasma-Mass Spectrometry with a High-Efficiency Sample Introduction System for Ultratrace Determination of 135Cs and 137Cs in Environmental Samples at Femtogram Levels

Analytical Chemistry

DOI: 10.1021/acs.analchem.6b02150

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Transient Heat and Solute Transfers in Liquid-Saturated Porous Media

Abstract

We investigate transient heat and solute transfers in liquid-saturated porous media. The macroscopic equivalent models are obtained by a homogenization process from the pore-scale description. The large value of the Lewis number in liquid mixtures introduces a possible separation of scales between the heat and solute diffusion wavelengths \(L^{\mathrm{heat}}\) and \(L^{\mathrm{solute}}\) at a given excitation time. Thus, two separations of scales could be present between the pore scale of characteristic length l and \(L^{\mathrm{heat}}\) and \(L^{\mathrm{solute}}\) . Depending on the ratio of these two separations of scales results in different equivalent macroscopic models or in non-homogenizable situations. Among numerous possibilities, we present two different homogenizable problems and a non-homogenizable situation. As the characteristic excitation time is decreased, the solute pseudo-wavelength and the heat pseudo-wavelength increase; a unique separation of scales between both solute and heat transfers and the pore scale appears, and we recover the classical macroscopic thermodiffusion model.

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Biocompatible Silk Noil-Based Three-Dimensional Carded-Needled Nonwoven Scaffolds Guide the Engineering of Novel Skin Connective Tissue

Tissue Engineering Part A Aug 2016, Vol. 22, No. 15-16: 1047-1060.


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