Giovanni Stefano

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Trafficking of secretory proteins between the endoplasmic reticulum (ER) and the Golgi apparatus depends on coat protein complexes I (COPI) and II (COPII) machineries. To date, full characterization of the distribution and dynamics of these machineries in plant cells remains elusive. Furthermore, except for a presumed linkage between COPI and COPII for the(More)
Two envelope membranes delimit plastids, the defining organelles of plant cells. The inner and outer envelope membranes are unique in their protein and lipid composition. Several studies have attempted to establish the proteome of these two membranes; however, differentiating between them is difficult due to their close proximity. Here, we describe a novel(More)
The endoplasmic reticulum (ER) is the key organelle at the start of the secretory pathway and the list of its functions is continually growing. The ER organization as a tubular/cisternal network at the cortex of plant cells has recently been shown to be governed by the membrane tubulation proteins of the reticulon family working alongside plant atlastin(More)
Proteins and traces of polysaccharide are the only polymeric colloids consistently transported in the xylem sap of plants. The hypothesis that such proteins could have physical inhibitory effects on xylem water transport was investigated. Ovalbumin, with a molecular weight of 45 kDa and a molecular diameter of 5.4 nm, is an inert, water-soluble protein that(More)
Early events in NaCl-induced root ion and water transport were investigated in maize (Zea mays L) roots using a range of microelectrode and imaging techniques. Addition of 100 mm NaCl to the bath resulted in an exponential drop in root xylem pressure, rapid depolarization of trans-root potential and a transient drop in xylem K(+) activity (A(K+) ) within ∼1(More)
Whether structure and function are correlated features of organelles is a fundamental question in cell biology. Here, we have assessed the ability of Arabidopsis mutants with a defective endoplasmic reticulum (ER) structure to invoke the unfolded protein response (UPR), an essential ER signaling pathway. Through molecular and genetic approaches, we show(More)
Leaf tissue tolerance was strongly and positively correlated with overall salt tolerance in barley, but not in wheat where the inability of sensitive varieties to exclude Na + is compensated by their better ability to handle Na + accumulated in the shoot via tissue tolerance mechanisms. A new high-throughput assay was developed to use the excised leaves to(More)
Eukaryotic cells internalize cargo at the plasma membrane via endocytosis, a vital process that is accomplished through a complex network of endosomal organelles. In mammalian cells, the ER is in close association with endosomes and regulates their fission. Nonetheless, the physiological role of such interaction on endocytosis is yet unexplored. Here, we(More)
The endoplasmic reticulum (ER) is an essential organelle that spreads throughout the cytoplasm as one interconnected network of narrow tubules and dilated cisternae that enclose a single lumen. The ER network undergoes extensive remodeling, which critically depends on membrane-cytoskeleton interactions [1]. In plants, the ER is also highly mobile, and its(More)
Letter to the editor the architectural integrity of the endoplasmic reticulum (er) network depends on the function of membrane-associated dyna-min-like GtPases that include metazoan atlastins, plant rhd3 and yeast Sey1p. the evidence that these proteins are sufficient to drive membrane fusion of reconstituted proteoliposomes, and that loss-of-function(More)