Tomato Rab11a Characterization Evidenced a Difference Between SYP121-Dependent and SYP122-Dependent exocytosis

The regulatory functions of Rab proteins in membrane trafficking lie in their ability to perform as molecular switches that oscillate between a GTP- and a GDP-bound conformation. The role of tomato LeRab11a in secretion was analyzed in tobacco protoplasts. Green fluorescent protein (GFP)/red fluorescent protein (RFP)-tagged LeRab11a was localized at the trans-Golgi network (TGN) in vivo. Two serines in the GTP-binding site of the protein were mutagenized, giving rise to the three mutants Rab11S22N, Rab11S27N and Rab11S22/27N. The double mutation reduced secretion of a marker protein, secRGUS (secreted rat β-glucuronidase), by half, whereas each of the single mutations alone had a much smaller effect, showing that both serines have to be mutated to obtain a dominant negative effect on LeRab11a function. The dominant negative mutant was used to determine whether Rab11 is involved in the pathway(s) regulated by the plasma membrane syntaxins SYP121 and SYP122. Co-expression of either of these GFP-tagged syntaxins with the dominant negative Rab11S22/27N mutant led to the appearance of endosomes, but co-expression of GFP-tagged SYP122 also labeled the endoplasmic reticulum and dotted structures. However, co-expression of Rab11S22/27N with SYP121 dominant negative mutants decreased secretion of secRGUS further compared with the expression of Rab11S22/27N alone, whereas co-expression of Rab11S22/27N with SYP122 had no synergistic effect. With the same essay, the difference between SYP121- and SYP122-dependent secretion was then evidenced. The results suggest that Rab11 regulates anterograde transport from the TGN to the plasma membrane and strongly implicate SYP122, rather than SYP121. The differential effect of LeRab11a supports the possibility that SYP121 and SYP122 drive independent secretory event

Ri-configurazione di parti ed elementi dell’architettura rurale: il recinto, la corte e la torre deI Yue jiazhuang nel Fujian in Cina/Re-configuration of parts and elements of rural architecture: the fence, the court and the tower of Yue jiazhuang in Fujian, China

Beyond the megalopolises, the high technology that has invaded local communities, there is a China made of architecture immersed in the greenery of large rice fields, high mountains and extensive bamboo forests. An agricultural China made up of men who carry huge baskets of vegetables on narrow walkways in beaten earth, which preserve habits that have been handed down for centuries as rituals of ways of life and adaptation to the land. This research work fits into this context, in continuity with the study trip made in March 2019, co-financed by the MAECI youth exchanges call, which allowed to deepen the knowledge and the study of fortifications in rammed earth typical of Fujian region. Tulou, tubao and zhuangzhai: three types of housing settlements with common characters, each with its own history and construction tradition to be investigated and told. The surveys of five zhuangzhai located in Yongtai county led us to choose the case study: the Yue jiazhuang. The design experimentation focused on the knowledge, interpretation, reconstruction and restoration of some parts in ruins and some demolished, using tools and methods of architectural survey, also through advanced digital 3D technologies and drones, architectural composition, restoration and regeneration urbanAl di là delle megalopoli, dell’alta tecnologia che ha invaso le comunità locali, esiste una Cina fatta di architetture immerse nel verde delle grandi risaie, delle alte montagne e degli estesi boschi di bambù. Una Cina agricola fatta di uomini che trasportano enormi ceste di ortaggi su stretti camminamenti in terra battuta, che conservano gli usi e i costumi che da secoli si tramandano come rituali di modi di vita e di adattamento alla terra. In questo contesto si colloca il lavoro di ricerca presentato, in continuità con il viaggio studio compiuto a marzo 2019, co-finanziato dal bando MAECI scambi giovanili, che ha permesso di approfondire la conoscenza e lo studio di fortificazioni in terra cruda proprie della regione del Fujian. Tulou, tubao e zhuangzhai: tre tipologie di insediamenti abitativi con caratteri comuni, ognuna con una propria storia ed una tradizione costruttiva da indagare e raccontare. I sopralluoghi a cinque zhuangzhai collocati nella contea di Yongtai, ci hanno condotto alla scelta del caso studio: lo Yue jiazhuang. La sperimentazione progettuale si è concentrata sulla conoscenza, interpretazione, ricostruzione e ripristino di alcune parti in rovina ed alcune totalmente demolite, avvalendosi di strumenti e metodi del rilevamento architettonico, anche mediante tecnologie avanzate digital3D e droni, della composizione architettonica, del restauro e della rigenerazione urbana

Tomato Rab11a characterization evidenced a difference between SYP121 dependent and SYP122 dependent exocytosis

The regulatory functions of Rab proteins in membrane trafficking lie in their ability to perform as molecular switches that oscillate between a GTP- and a GDP-bound conformation. The role of tomato LeRab11a in secretion was analyzed in tobacco protoplasts. Green fluorescent protein (GFP)/red fluorescent protein (RFP)-tagged LeRab11a was localized at the trans-Golgi network (TGN) in vivo. Two serines in the GTP-binding site of the protein were mutagenized, giving rise to the three mutants Rab11S22N, Rab11S27N and Rab11S22/27N. The double mutation reduced secretion of a marker protein, secRGUS (secreted rat b-glucuronidase), by half, whereas each of the single mutations alone had a much smaller effect, showing that both serines have to be mutated to obtain a dominant negative effect on LeRab11a function. The dominant negative mutant was used to determine whether Rab11 is involved in the pathway(s) regulated by the plasma membrane syntaxins SYP121 and SYP122. Co-expression of either of these GFP-tagged syntaxins with the dominant negative Rab11S22/27N mutant led to the appearance of endosomes, but co-expression of GFP-tagged SYP122 also labeled the endoplasmic reticulum and dotted structures. However, co-expression of Rab11S22/27N with SYP121 dominant negative mutants decreased secretion of secRGUS further compared with the expression of Rab11S22/27N alone, whereas co-expression of Rab11S22/27N with SYP122 had no synergistic effect. With the same essay, the difference between SYP121- and SYP122-dependent secretion was then evidenced. The results suggest that Rab11 regulates anter- ograde transport from the TGN to the plasma membrane and strongly implicate SYP122, rather than SYP121. The differential effect of LeRab11a supports the possibility that SYP121 and SYP122 drive independent secretory events

Down-regulation of the mitochondrial aspartate-glutamate carrier isoform 1 AGC1 inhibits proliferation and N-acetylaspartate synthesis in Neuro2A cells

The mitochondrial aspartate-glutamate carrier isoform 1 (AGC1) catalyzes a Ca(2+)-stimulated export of aspartate to the cytosol in exchange for glutamate, and is a key component of the malate-aspartate shuttle which transfers NADH reducing equivalents from the cytosol to mitochondria. By sustaining the complete glucose oxidation, AGC1 is thought to be important in providing energy for cells, in particular in the CNS and muscle where this protein is mainly expressed. Defects in the AGC1 gene cause AGC1 deficiency, an infantile encephalopathy with delayed myelination and reduced brain N-acetylaspartate (NAA) levels, the precursor of myelin synthesis in the CNS. Here, we show that undifferentiated Neuro2A cells with down-regulated AGC1 display a significant proliferation deficit associated with reduced mitochondrial respiration, and are unable to synthesize NAA properly. In the presence of high glutamine oxidation, cells with reduced AGC1 restore cell proliferation, although oxidative stress increases and NAA synthesis deficit persists. Our data suggest that the cellular energetic deficit due to AGC1 impairment is associated with inappropriate aspartate levels to support neuronal proliferation when glutamine is not used as metabolic substrate, and we propose that delayed myelination in AGC1 deficiency patients could be attributable, at least in part, to neuronal loss combined with lack of NAA synthesis occurring during the nervous system development