SEC18/NSF-independent, protein-sorting pathway from the yeast cortical ER to the plasma membrane

Classic studies of temperature-sensitive secretory (sec) mutants have demonstrated that secreted and plasma membrane proteins follow a common SEC pathway via the endoplasmic reticulum (ER), Golgi apparatus, and secretory vesicles to the cell periphery. The yeast protein Ist2p, which is synthesized from a localized mRNA, travels from the ER to the plasma membrane via a novel route that operates independently of the formation of coat protein complex II–coated vesicles. In this study, we show that the COOH-terminal domain of Ist2p is necessary and sufficient to mediate SEC18-independent sorting when it is positioned at the COOH terminus of different integral membrane proteins and exposed to the cytoplasm. This domain functions as a dominant plasma membrane localization determinant that overrides other protein sorting signals. Based on these observations, we suggest a local synthesis of Ist2p at cortical ER sites, from where the protein is sorted by a novel mechanism to the plasma membrane

Study of surface treated historical materials

Import 05/08/2014Diplomová práce se zabývá obecným studiem povrchových úprav technikou plátkového zlacení na historických předmětech, zejména obrazových rámech. V teoretické části práce pojednává o historii a principech zhotovování technologií zlacení povrchu různých materiálů od minulosti k současnosti. Zřetel je kladen na dřevěné obrazové rámy a jejich části. Cílem práce je průzkum složení povrchových úprav a to jak složení slitiny použitého plátkového kovu, tak složení pojiv a podkladové vrstvy. Experimentální část je zaměřena na průzkum povrchu historických předmětů pomocí skenovací elektronové mikroskopie a analýzu typu syntetických pryskyřic rámů pomocí spektroskopických a chromatografických metod.This thesis deals with the general study of finishes leaf gilding technique on historical subjects, especially picture frames. The theoretical part deals with the history and principles of making technology gilding the surface of various materials from past to present. Consideration shall be given to the wooden picture frames and parts. The aim of the work is investigation of the finishes in both the composition of the alloy used leaf metal and binder composition and the underlying layer. The experimental part will focus on exploration of historical objects surface using scanning electron microscopy and analysis of the type of synthetic resin frames using chromatographic methods.636 - Katedra materiálového inženýrstvívýborn

Afadin controls cell polarization and mitotic spindle orientation in developing cortical radial glia.

BackgroundIn developing tissues, cell polarity and tissue architecture play essential roles in the regulation of proliferation and differentiation. During cerebral cortical development, adherens junctions link highly polarized radial glial cells in a neurogenic niche that controls their behavior. How adherens junctions regulate radial glial cell polarity and/or differentiation in mammalian cortical development is poorly understood.ResultsConditional deletion of Afadin, a protein required for formation and maintenance of epithelial tissues, leads to abnormalities in radial glial cell polarity and subsequent loss of adherens junctions. We observed increased numbers of obliquely-oriented progenitor cell divisions, increased exit from the ventricular zone neuroepithelium, and increased production of intermediate progenitors.ConclusionsTogether, these findings indicate that Afadin plays an essential role in regulating apical-basal polarity and adherens junction integrity of radial glial cells, and suggest that epithelial architecture plays an important role in radial glial identity by regulating mitotic orientation and preventing premature exit from the neurogenic niche

Additional file 2: Figure S2. of Afadin controls cell polarization and mitotic spindle orientation in developing cortical radial glia

Expression of adherens junction-associated proteins in control and Afadin-deleted dorsal forebrains at E13.5. (A, B) Western blot analysis of E13.5 dorsal forebrain extracts show a strong reduction of Afadin expression in mutant, but not of intercellular junctions-associated proteins α-catenin, N-cadherin, β-catenin, p120catenin, Z0-1, or any cadherin when compared to control (mean ± s.d. Unpaired t-test.; n = 3 to 8 animals). (TIF 2373 kb

Dominant optic atrophy: culprit mitochondria in the optic nerve

Dominant optic atrophy (DOA) is an inherited mitochondrial disease leading to specific degeneration of retinal ganglion cells (RGCs), thus compromising transmission of visual information from the retina to the brain. Usually, DOA starts during childhood and evolves to poor vision or legal blindness, affecting the central vision, whilst sparing the peripheral visual field. In 20% of cases, DOA presents as syndromic disorder, with secondary symptoms affecting neuronal and muscular functions. Twenty years ago, we demonstrated that heterozygous mutations in OPA1 are the most frequent molecular cause of DOA. Since then, variants in additional genes, whose functions in many instances converge with those of OPA1, have been identified by next generation sequencing. OPA1 encodes a dynamin-related GTPase imported into mitochondria and located to the inner membrane and intermembrane space. The many OPA1 isoforms, resulting from alternative splicing of three exons, form complex homopolymers that structure mitochondrial cristae, and contribute to fusion of the outer membrane, thus shaping the whole mitochondrial network. Moreover, OPA1 is required for oxidative phosphorylation, maintenance of mitochondrial genome, calcium homeostasis and regulation of apoptosis, thus making OPA1 the Swiss army-knife of mitochondria. Understanding DOA pathophysiology requires the understanding of RGC peculiarities with respect to OPA1 functions. Besides the tremendous energy requirements of RGCs to relay visual information from the eye to the brain, these neurons present unique features related to their differential environments in the retina, and to the anatomical transition occurring at the lamina cribrosa, which parallel major adaptations of mitochondrial physiology and shape, in the pre- and post-laminar segments of the optic nerve. Three DOA mouse models, with different Opa1 mutations, have been generated to study intrinsic mechanisms responsible for RGC degeneration, and these have further revealed secondary symptoms related to mitochondrial dysfunctions, mirroring the more severe syndromic phenotypes seen in a subgroup of patients. Metabolomics analyses of cells, mouse organs and patient plasma mutated for OPA1 revealed new unexpected pathophysiological mechanisms related to mitochondrial dysfunction, and biomarkers correlated quantitatively to the severity of the disease. Here, we review and synthesize these data, and propose different approaches for embracing possible therapies to fulfil the unmet clinical needs of this disease, and provide hope to affected DOA patients