de Bernard M, Arico B, Papini E, Rizzuto R, Grandi G, Rappuoli R, Montecucco C
Centro CNR Biomembrane and Dipartimento di Scienze Biomediche Sperimentali dell'Università di Padova, Italy.
Mol Microbiol. 1997 Nov;26(4):665-74. doi: 10.1046/j.1365-2958.1997.5881952.x.
Cells exposed to Helicobacter pylori toxin VacA develop large vacuoles that originate from massive swelling of membranous compartments of late stages of the endocytic pathway. To determine if the toxin is active from the cell cytosol, cells were either microinjected with toxin or transfected with plasmids encoding VacA. Both procedures cause formation of intracellular vacuoles. Cytosolic localization of the toxin was assessed by indirect immunofluorescence with specific antibodies and by expression of an active green fluorescence protein (GFP)-VacA chimera. Vacuoles induced by internally produced VacA are morphologically and functionally identical to those induced by externally added toxin. It is concluded that VacA is a toxin acting intracellularly by altering a cytosol-exposed target, possibly involved in the control of membrane trafficking.
暴露于幽门螺杆菌毒素VacA的细胞会形成大液泡，这些液泡源于内吞途径后期膜性区室的大量肿胀。为了确定该毒素在细胞胞质溶胶中是否具有活性，对细胞进行了微注射毒素或用编码VacA的质粒转染。这两种操作都会导致细胞内液泡的形成。通过使用特异性抗体的间接免疫荧光以及活性绿色荧光蛋白（GFP）-VacA嵌合体的表达来评估毒素的胞质溶胶定位。由内源性产生的VacA诱导的液泡在形态和功能上与外源性添加毒素诱导的液泡相同。得出的结论是，VacA是一种通过改变暴露于胞质溶胶的靶点在细胞内起作用的毒素，该靶点可能参与膜运输的调控。
