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      Nuclear Membrane Dynamics and Reassembly in Living Cells: Targeting of an Inner Nuclear Membrane Protein in Interphase and Mitosis

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          Abstract

          The mechanisms of localization and retention of membrane proteins in the inner nuclear membrane and the fate of this membrane system during mitosis were studied in living cells using the inner nuclear membrane protein, lamin B receptor, fused to green fluorescent protein (LBR–GFP). Photobleaching techniques revealed the majority of LBR–GFP to be completely immobilized in the nuclear envelope (NE) of interphase cells, suggesting a tight binding to heterochromatin and/or lamins. A subpopulation of LBR–GFP within ER membranes, by contrast, was entirely mobile and diffused rapidly and freely ( D = 0.41 ± 0.1 μm 2/s). High resolution confocal time-lapse imaging in mitotic cells revealed LBR–GFP redistributing into the interconnected ER membrane system in prometaphase, exhibiting the same high mobility and diffusion constant as observed in interphase ER membranes. LBR–GFP rapidly diffused across the cell within the membrane network defined by the ER, suggesting the integrity of the ER was maintained in mitosis, with little or no fragmentation and vesiculation. At the end of mitosis, nuclear membrane reformation coincided with immobilization of LBR–GFP in ER elements at contact sites with chromatin. LBR–GFP–containing ER membranes then wrapped around chromatin over the course of 2–3 min, quickly and efficiently compartmentalizing nuclear material. Expansion of the NE followed over the course of 30–80 min. Thus, selective changes in lateral mobility of LBR–GFP within the ER/NE membrane system form the basis for its localization to the inner nuclear membrane during interphase. Such changes, rather than vesiculation mechanisms, also underlie the redistribution of this molecule during NE disassembly and reformation in mitosis.

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          Most cited references 57

          • Record: found
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          Green fluorescent protein as a marker for gene expression.

          A complementary DNA for the Aequorea victoria green fluorescent protein (GFP) produces a fluorescent product when expressed in prokaryotic (Escherichia coli) or eukaryotic (Caenorhabditis elegans) cells. Because exogenous substrates and cofactors are not required for this fluorescence, GFP expression can be used to monitor gene expression and protein localization in living organisms.
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            • Record: found
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            • Article: not found

            Protein sorting by transport vesicles.

            Eukaryotic life depends on the spatial and temporal organization of cellular membrane systems. Recent advances in understanding the machinery of vesicle transport have established general principles that underlie a broad variety of physiological processes, including cell surface growth, the biogenesis of distinct intracellular organelles, endocytosis, and the controlled release of hormones and neurotransmitters.
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              • Record: found
              • Abstract: found
              • Article: not found

              Diffusional mobility of Golgi proteins in membranes of living cells.

              The mechanism by which Golgi membrane proteins are retained within the Golgi complex in the midst of a continuous flow of protein and lipid is not yet understood. The diffusional mobilities of mammalian Golgi membrane proteins fused with green fluorescent protein from Aequorea victoria were measured in living HeLa cells with the fluorescence photobleaching recovery technique. The diffusion coefficients ranged from 3 x 10(-9) square centimeters per second to 5 x 10(-9) square centimeters per second, with greater than 90 percent of the chimeric proteins mobile. Extensive lateral diffusion of the chimeric proteins occurred between Golgi stacks. Thus, the chimeras diffuse rapidly and freely in Golgi membranes, which suggests that Golgi targeting and retention of these molecules does not depend on protein immobilization.
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                Author and article information

                Journal
                J Cell Biol
                The Journal of Cell Biology
                The Rockefeller University Press
                0021-9525
                1540-8140
                22 September 1997
                : 138
                : 6
                : 1193-1206
                Affiliations
                [* ]Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health (NIH), Bethesda, Maryland 20892; []Department of Physics, Cornell University, Ithaca, New York 14853; [§ ]Light Imaging Facility, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland 20892; and []Departments of Medicine and of Anatomy and Cell Biology, College of Physicians and Surgeons, Columbia University, New York 10032
                Article
                2132565
                9298976
                Categories
                Article

                Cell biology

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