A Deubiquitylating Complex Required for Neosynthesis of a Yeast Mitochondrial ATP Synthase Subunit

The ubiquitin system is known to be involved in maintaining the integrity of mitochondria, but little is known about the role of deubiquitylating (DUB) enzymes in such functions. Budding yeast cells deleted for UBP13 and its close homolog UBP9 displayed a high incidence of petite colonies and slow respiratory growth at 37°C. Both Ubp9 and Ubp13 interacted directly with Duf1 (DUB-associated factor 1), a WD40 motif-containing protein. Duf1 activates the DUB activity of recombinant Ubp9 and Ubp13 in vitro and deletion of DUF1 resulted in the same respiratory phenotype as the deletion of both UBP9 and UBP13. We show that the mitochondrial defects of these mutants resulted from a strong decrease at 37°C in the de novo biosynthesis of Atp9, a membrane-bound component of ATP synthase encoded by mitochondrial DNA. The defect appears at the level of ATP9 mRNA translation, while its maturation remained unchanged in the mutants. This study describes a new role of the ubiquitin system in mitochondrial biogenesis

De la mer Baltique à l'Océan indien. Destinées suédoises en terre australe

From the Baltic Sea to the Indian Ocean Suedish Destinies in Australia. Sophie Grimal. This article focuses on the Swedish immigrants who settled in Western Australia between 1830 and 1930. In keeping with their ancestors' tendency to adjust to widely different cultural environments, the first Swedes who tried their luck in Australia adapted rapidly to their new homeland. Thanks to their ancestral seafaring tradition, the Scandinavian voyagers were among the first Europeans who discovered Terra Australis Incognita in 1642 and 1778. They were also among the first settlers « Down Under » in the XIXth century. When the British authorities sent the first pioneers to Western Australia to found the so-called « Swan River Colony » in 1830, there were five Swedish servants among the settlers. Then, in the 1850's, as trade developed between Australia and Scandinavia, Swedish vessels started to stop in Australia on a regular basis and the country became a possible destination for would be immigrants. During the gold rush in the 1880's and 1890's, Swedes made for the gold fields in the northern and the central parts of Western Australia. Even when Perth and Fremantle became major trade centers, the Swedish pioneers still yielded to the call of adventure in the outback. At that time, the Swedes of Australia were of two kinds: either they remained in urban areas and became successful businessmen, or they lived as free spirits in the bush. Both kinds became integrated in the Australian culture, as their tendency to anglicise their names goes to show. Although they adjusted apparently quite well to the Australian way of life, they did not forget their native culture. When the communities became big enough, they started social clubs and tried to keep Swedish traditions alive. Their tendency to adjust while retaining their cultural specificities remains up till now the main characteristic of the Swedish communities.Frän Östersjön till Indiska Oceanen Svenska emigranter i Australien Denna här artikel hand om de svenskar emigranter, som utvandrade till Västaustralien 1830-1930. Liksom dera forfader, som var benägna for att anpassa sig till diverse kulturella miljoer, assimilerades de första svenska australienfararna ganska snabbt. Tack vare den urgamla nordiska sjofartstraditionen, fanns det skandinaviska sjömän ombord de första upptäcktsfärderna till Terra Australis Incognita 1642 och 1778. Svenskarna var ocksä ibland de första europeiska pionjärerna «Down Under» i det 1800-talet. När englesmannen besluttade sig att grunda den sa kallade « Svanfloden kolonien » i Västaustralien 1830, äkade fem svenskar tjanare med till det nya landet. Nar handeln med Australien utvecklade i 1850-talet, blev sjofart till Antipoderna intensivare och Australien blev ett utvandringsmäl. Under guldrushen, 1880 och 1890, fanns det svenskar bland guldgrävarna i vildmarker i Vâstaustralien. Nar Perth/ Fremantle blev ett viktigt handelscentrum, fanns det fortfarande aventyrare som provade lyckan i den australiska « outback ». Pä den tiden fanns det tvä slags svenska immigranter : antingen de som bosat sig i städerna och blev framgängsrika affärsmän eller de som äkade till bushen. Bäda assimileras i den australiska kulturen och ofta angliciserade de deras namn. Fastan de anpassade sig ganska bra till det australiska samhället, glömde de inte deras egen kultur. Nar immigranternas grupper blev stora, stiftade svenskarna foreningar och klubber for att behalla traditionerna och det nationella identitet. Hos dem stred benägenheten att assimileras inte mot etnicitet. Det här egenskapet att forena de tvä motsättliga tendenser har alltid varit de svenska immigranternas kannetecken.Del mar Báltico al Océano Índico. Destinos suecos en tierra austral. Este artículo presenta a un grupo de inmigrantes suecos que se instaló en Australia Occidental entre 1830 y 1930. A semejanza de los pioneros escandinavos que, desde el siglo IX, se integraron fácilmente en medios culturales y lingüísticos de gran diversidad, los primeros suecos que intentaron la aventura australiana se adaptaron rápidamente a su nuevo entorno. Gracias a su vocación de marinos y de viajeros, los escandinavos fueron de los primeros europeos en descubrir la Terra Australis Incognito en los siglos XVII y XVIII, y en instalarse en el siglo XIX. Así, cuando los británicos enviaron, en 1830, a los primeros pioneros a Australia Occidental para fundar la "colonia del Rio de los cisnes", algunos de ellos eran suecos. Además, hacia 1850, los puertos del oeste y del sur ganaban en importancia y los marinos suecos los visitaban regularmente desertando a menudo de su buque. En el momento de las estampidas del oro de los años 1880-90, partieron a los campos auríferos del norte y del centro del Estado. Incluso durante el auge de la vida urbana de la zona de Perth-Fremantle, ellos continuaron cediendo a la tentación de la aventura en el outback, el interior de Australia. Los emigrantes suecos se repartieron, entonces, en dos grupos igualmente integrados en la vida y cultura australianas : los ciudadanos que prosperarían en las zonas portuarias y los aventureras del bush. Los inmigrantes de estos dos grupos se adaptaron a su nuevo entorno, a menudo bajo un apellido anglicanizado, sin olvidar, de todos modos, sus origenes y fundando, hacia el cambio de siglo, los primeros clubes y sociedades escandinavas. Esta doble pertenencia cultural y lingüística continuara existiendo hasta nuestros días permitiendo la integración de los emigrantes suecos en la sociedad australiana sin desaparecer.Grimal Sophie. De la mer Baltique à l'Océan indien. Destinées suédoises en terre australe. In: Revue européenne des migrations internationales, vol. 15, n°3,1999. pp. 223-238

Collagen XVI is a neural component of the developing and regenerating dorsal root ganglia extracellular matrix.

International audienceCollagen XVI is a homotrimeric molecule harbouring similarities to the FACIT (fibril-associated collagens with interrupted triple helices) family of collagens (Grassel et al., 1996). Collagen XVI is expressed in skin and cartilage where it is integrated into tissue specific aggregates (Grassel et al., 1999; Kassner et al., 2003). In the nervous system, collagen XVI has been detected at lowlevel in the brain and a strong expression was also reported in spinal root fibers during development (Lai and Chu, 1996). In dorsal root ganglia (DRG), analysis of SAGE banks performed by our group during development and after nerve injury (Mechaly et al., 2006) shows a fluctuation of collagen XVI expression between the different conditions and prompted us to study it further. DRGs contain the cell bodies of neurons, the axons of which transmit sensory information from the periphery to the central nervous system. While it is well known that during development and regeneration, neurites require extracellular matrix molecules for growth and guidance (Hari et al., 2004), the composition and the role of the matrix surrounding neurons in the ganglia itself have solicited little interest. Here, we show that collagen XVI is a component of the developingDRG extracellular matrix, that following nerve injury, its expression is increased around neuronal cell bodies and that neurons express collagen XVI in the peripheral nervous system

Collagen XXVIII Is a Distinctive Component of the Peripheral Nervous System Nodes of Ranvier and Surrounds Nonmyelinating Glial Cells

Growing evidence indicates that collagens perform crucial functions during the development and organization of the nervous system. Collagen XXVIII is a recently discovered collagen almost exclusively expressed in the peripheral nervous system (PNS). In this study, we show that this collagen is associated with nonmyelinated regions of the PNS. With the notable exception of type II terminal Schwann cell in the hairy skin, collagen XXVIII surrounds all nonmyelinating glial cells studied. This includes satellite glial cells of the dorsal root ganglia, terminal Schwann cells type I around mechanoceptors in the skin, terminal Schwann cells around proprioceptors in the muscle spindle or at the neuromuscular junction and olfactory ensheathing cells. Collagen XXVIII is also detected at nodes of Ranvier where the myelin sheath of myelinated fibers is interrupted and is thus a distinctive component of the PNS nodal gap. The correlation between the absence of myelin and the presence of collagen XXVIII is confirmed in a mouse model of Charcot-Marie-Tooth characterized by dysmyelinated nerve fibers, in which enhancement of collagen XXVIII labeling is observed. (C) 2010 Wiley-Liss, Inc

Respiratory growth of yeast <i>ubp</i> mutants.

<p>Dilution series of wild-type BY4741 (WT) and Δ<i>ubpx</i> strains were grown on media containing fermentable (glucose) or respiratory (lactate) substrates, at 30°C, for 3 and 5 days, respectively. Similar results were obtained with ethanol and glycerol as respiratory substrates.</p

Δ<i>ubp9</i> Δ<i>ubp13</i>, Δ<i>duf1</i> and Δ<i>ubp9</i>Δ<i>ubp13</i>Δ<i>duf1</i> cells display defective respiration.

<p>Cells grown on galactose at 37°C to the exponential phase, were diluted in potassium buffer pH 7.2 and placed for a few hours at 37°C. Respiratory growth was then measured on entire cells, after the addition of 0.2% galactose, over a period of 7 min, with a Clark-Type electrode, as previously described <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0038071#pone.0038071-Blaiseau1" target="_blank">[51]</a>.</p

Both Ubp9 and Ubp13 interact with Duf1, a WD40 protein of unknown function.

<p>A. Ubp9 and Ubp13 coimmunoprecipitate with Duf1. Cells grown on lactate medium and expressing chromosome-encoded Duf1-GFP, and Ubp9-HA or Ubp13p-HA, were subjected to immunoprecipitation in native conditions using GFP antibodies. Total extracts (input, IN), and immunoprecipitates (IP) were tested by immunoblotting with anti-HA and anti-phopsphoglycerol kinase (PGK) antibodies. The same experiment was performed on Δ<i>ubp9</i> Δ<i>ubp13</i> expressing chromosomal-encoded Duf1-GFP (left) and plasmid-encoded Ubps (right). B. Ubp9 and Ubp13 interact with Duf1 in glutathione S-transferase (GST) pull-down assays. GST, GST-tagged Ubp9 and GST-tagged Ubp13 were purified with glutathione-Sepharose beads and incubated with extracts from cells producing Duf1-HA. Total extracts (IN), unbound (NB) and bound (B) fractions were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting with an anti-HA antibody. C. Ubp9 and Ubp13 interact directly with Duf1. The GST-pull down assay was performed as described in panel B, except that a bacterial extract producing 6His-Duf1 was used. 6His-Duf1 was detected with an anti-His antibody.</p

Δ<i>ubp9</i> Δ<i>ubp13</i> and Δ<i>duf1</i> mutants have a similar respiratory phenotype, which is not aggravated by the deletion of <i>UBP16</i>.

<p>Dilution series of wild-type BY4741 (WT), Δ<i>ubp9</i>, Δ<i>ubp13,</i> Δ<i>ubp16,</i> Δ<i>ubp9</i> Δ<i>ubp13</i>, Δ<i>duf1,</i> Δ<i>ubp9</i> Δ<i>ubp13</i> Δ<i>ubp16</i> and Δ<i>ubp9</i> Δ<i>ubp13</i> Δ<i>duf1</i> strains were grown on medium containing fermentable (glucose) or respiratory (lactate) substrates for 5 days at 30°C and 37°C.</p

Genotypes and sources of yeast strains.

<p>Δ<i>ubpn</i> refers to a collection of strains, each with the deletion of a single <i>UBP</i> gene (1≤ n ≤16).</p